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Welcome to the Electric Car Weblog. In addition to links, news, and tips about electric cars and other forms of alternative transportation we are publishing an on-line diary of our current EV project. Started in August 2005 the chronicle follows the conversion of a gas powered Ford Probe into an Electric Car.

You will find articles organized by categories, along with recent comments, along the right hand column of the website. If you are just getting started with the idea of converting a gas car to electric be sure to check out Your First Electric Car

Welcome and enjoy!

Battery Tools · 20 June 06

Odyssey PC2150

Hey, we’re getting closer to settling on a battery! Those who have been following the comments elsewhere may have read that I started looking into the Odyssey Hawker PC2150 battery. More expensive (nothing like NiMH/Lithium prices) and from everything I’ve read they are well built (mil spec) and able to take or dish-out lots of power.

Of course John Westlund then jumps into the comments and mentions another, cheaper battery and doubt sets in…

Welcome to the whacky world of EV Batteries!

The whole battery thing has more or less brought everything else to a standstill. When making an EV the battery really dictates pretty much everything else, both physically and psychologically.

Physically it influences where you put other components, how much cable you’ll need for interconnects, metal-work and welding requirements, weight distribution (and therefore suspension), the type of charger, and whether you’ll need more battery management systems.

Psychologically the process will try every bit of patience you ever thought you had. You’ll start off confident and with purpose only to end up full of doubt and confused, checking and re-checking a hundreds of websites, making phone calls, staring at spec sheets, and computing peukert until you puke.

There’s a lot to be said about going with a kit where all of these designs and decisions have been made for you.

But I’m not here to whine, I’m here to share.

I’ve pointed to a couple of EV Calculators in the past and, trust me, I’ve spent countless hours using them over the past months. There’s a few problems: neither of them have Eve’s specs or include most of the batteries I’ve been researching (so lots of typing and re-typing), they don’t save/bookmark your setup, and the pages themselves are huge.

I’m not trying to cut them down, they have been a godsend, just saying that there’s data and features that I’ve wanted to add. That and you know how I like to pretty things up. ’:^)

Over the weekend I spent some time doing just that: modifying the existing code, loading data into databases, messing with user interface ideas, and adding new features. Ladies and Gentlemen, let me introduce the all-new EVConvert.com EV Calculator.

EVConvert new EV Calculator Screenshot

First a few disclaimers:

  • this is a work in progress (i.e. bugs!)
  • the data is was gathered on the web (i.e. bugs!)
  • it probably doesn’t work in IE (who cares! uh, sorry, I mean: bug)
  • more features coming soon (i.e. new bugs!)

The basic premise is that you pick a vehicle, motor, battery, and controller, tweak a few of the additional parameters and then click calculate. If everything is working correctly (and it may not) you should see numbers show up in the range columns. The data blocks have little arrows which expose even more data.

The goal was to provide a one-page interface that makes it easy to tweak a parameter and see the change quickly, yet still be able to expand the layout when more information is needed.

Current features:

  • database driven design (with AJAX for buzzword compliance!)
  • cookies used to remember your last settings
  • separate batteries page for more information
  • cleaned up number formatting
  • updated battery list

Things to do:

  • ability for you to add your own vehicle along with new batteries, motors & controllers
  • nicely formatted printing
  • more formatting to clean up
  • only remembers popup selections (vehicle/motor/controller/battery), none of the additional hand entered data
  • add battery cost to summary
  • add tool-tip help text
  • add battery dimensions
  • use the battery data for the battery layout tool
  • compute more battery related statistics, much like those in the battery spreadsheet posted awhile back
  • add graphs, blinking text, dancing badgers!

This will be part of my slowly growing EV toolkit. Here’s what we have so far:

  • EV Calculator – helps in evaluating components and design choices
  • EV Batteries – the batteries used in the calculator, with more details and tools to add new batteries (that part is coming soon)
  • EV Battery Layout – simple gizmo I made to help experiment with battery box layouts

Give them a try and then leave a comment or drop me an email with your thoughts, feature ideas, and any bugs you find.

Some other points that I should make a note of. The other EV Calculators default to low rolling resistance tires (0.0015 tire resistance) and perfectly flat terrain. This makes your range look REALLY nice. But it’s not very realistic for most of us so I’ve changed this calculator to default to normal tires and a modest 1% grade.

If I had all of the time in the world (and a few more brain cells) I’d make it so you could upload a GPS tracklog, correlate that with digital elevation models, and compute the range for your exact driving conditions.

Comments 96
  1. — Ed Cochran    Jun 20, 2006 13:57 PM    #

    page looks great but revs per minute was zero so it could not calculate—what do i need to put in for a brusa motor – controller and a sentra body 2000 year to present.

  2. jerry    Jun 20, 2006 14:34 PM    #

    Hi Ed,

    I noticed some of the motor entries are suspect and will need to clean them up later on.

    If you have something that’s not in the popup list you’ll need to pick something close and then open the details and put in the values for your item. Soon I plan to add the ability to save them as well.

    Here’s Uve’s Motor page, which might help to figure out the other values.

  3. — John Westlund    Jun 21, 2006 00:25 AM    #

    If you’re that uncertain about which battery to use, then use a general ‘rule of thumb’ instead of a complex simulation.

    In regards to range, the general rule of thumb is that 800 pounds of batteries will take you as far as one gallon of gas would in that same glider. Avoids all the fuss, and you’ll be accurate within +/- 10% for the vast majority of cases.

    The reality is, you will not get the exact specs you design for, because of other factors like weather and driving style that come into play.

    Simulations are useful, but to a point. For today’s lead acid batteries, there is very little variance in specific capacity, so using the general rule of thumb, you can eliminate one or more factors.

    By simplifying the process, you stop sitting on your ass crunching numbers and jump right into converting.

    What is important to you? Cost per mile? Range? Performance? Virtually all lead acid batteries will give you the same range per pound of battery, few exceptions. Performance? Be prepared to pay for it. Lowest cost per mile possible, look around, but floodies are usually the best choice while my conjecture is that Hawkers will be the worst in this regard(That may or may not be the case).

    Those AGMs I mentioned, I do not know their cycle life or how well they can provide 700 amp discharges and whether or not they will take damage from that. I have no personal experience with them. Get ahold of Cor Van DeWater. He has a set of the UB121100s in his electric S10. You may be able to pick his brain for the ever important cycle life numbers that he has attained under his application, even if he is still using his pack and hasn’t had to swap it yet.

    I should be one to talk of course, as I will again state my conversion is not on the road yet! I have never built an EV, so take my advice for the value of what you paid for it.

    But getting ahold of information, and settling with slightly innaccurate estimates is what will get your conversion going.

    Can’t wait to see what you do with that car.

    If I had the car and cash you had, I’d think of trying an HV Zilla 1k, 9” motor, and a 240V string of UB121100s. This would be a 1,460 pound chunk of lead in that car. I’d then aeromod the f**k out of it, to maximize efficiency and range. Full underbelly, grill block, rear wheel skirts, tapered rear spoiler, shaved door handle kit, removed rain gutters and antenna, the works.

    I don’t know how well these batteries would hold up, but then again, I’m more of the risk taker type. The payoff could potentially be huge if you made the right choice, but if you made the wrong choice, these batteries are as cheap as floodies anyway. Can’t say that for Hawkers, as those look dreadfully expensive!

    And besides, a 1,460 pound pack of lead in heavily modified body that only needed 200 wh/mile, equals long ass highway range. That’s how those large electric pickups like Red Beastie do 120 miles per charge. With either floodies or those cheap AGMs, it can be done relatively inexpensivevly, at least in theory. In practice, others have done it, even if you or I personally haven’t.

    Good luck. Most battery configurations will probably meet the goals you outlined.

  4. — kert    Jun 21, 2006 02:54 AM    #

    any chance of getting the A123 cells data in the battery database ?
    They retail in deWalt 36V packs for $150 (SKU# DC9360 ) and some specs are up here:

  5. — kert    Jun 21, 2006 03:01 AM    #

    of course there are also the Milwaukee 28V bats, the specs are on the same page.
    Other powertools vendors like Metabo, Makita and Bosch also offer li-ion packs but the specs are hard to find.
    Bosch is more interesting as they claim very long cycle life, anyone knows which cells are in there ? They are also most expensive, with around $180 for 36V pack.

  6. — John Westlund    Jun 21, 2006 05:07 AM    #

    I wouldn’t even bother with those A123 batteries. You you realize how horrendously complicated a BMS is going to be for those?

    Rich Rudman is working on one, I think, but it might take on the order of two years. If Rich can’t do it yet, your average hobbyist sure as hell isn’t going to.

    Of course, I could be incorrect. He might indeed have developed a working BMS for these, but as far as I know, he’s still working on one.

    During that Monster Garage episode, all of them batteries had their own individual charger. That is far from practical for a hobbyist or someone wishing to commute with their EV.

  7. Shaun Williams    Jun 21, 2006 05:43 AM    #

    This is great Jerry. I got caught out REAL BAD with my naive virgin calculations because of the rarely mentioned “hill” factor.

    A quick play with the incline on your calculator spells it out real quick! Newbies TAKE NOTE.

  8. Jerry    Jun 21, 2006 07:17 AM    #

    I pretty much know what I want: 12v ~100aH AGM non-flooded. And, to me, that seemed like the simplest thing in the world to figure out. But what’s happened is that as I investigate the various batteries I find:

    a) no one sells it
    b) the battery doesn’t like EV level current draws
    c) it’s really expensive (and no warranty)
    d) no one has ever tried it in an EV
    e) EV owners don’t like it
    f) you need two lower aH batteries in parallel to get an effective 100aH

    And it takes a few days or a week to reach this conclusion. C & D are somewhat tractable, but if I’m going to go that route I try to do more research to see if there’s something I’m missing.

    Batteries are not created equal. The specs are, for the most part, approximate numbers stretched thin by marketing. Some companies (like Odyssey) publish great numbers, others like US Battery publish the bare minimum. Now US Battery floodeds are used primarily because of word of mouth, from an EV supplier or another EV owner, but you can’t compare them directly since there’s not enough data to derive the peukerts. Someone took a chance and tried them out XX years ago and the rest of us have benefited.

    I’ve mentioned this story before, but on our first EV the first pack of Trojan SCS-225’s were reaching the end of their life and went to order another pack. The supplier said “just buy something with equivalent numbers from *mart and save yourself a few bucks.” I got a battery which had almost the exact same specs (as much as was published) and even looked similar. The battery barely lasted a year. Replaced with another set of Trojans and they lasted three years like the first set.

    The UB121100 batteries look a lot like Powersonic PS121000 AGMs which is used predominately for UPS systems. Cor hasn’t responded to my email yet, but another fellow has and is generally happy with the batteries after a hundred or so miles of use.

    The final challenge is buying the batteries. I live in a small town, so most of the research is web based followed up by phone calls to nearby distributors. Prices are all over the map. The web is a great research resource, it is also an outdated and untrustworthy at times. The price of lead has gone up quite a bit in the last year, which means the price of batteries has risen as well. Many of these onlines stores are little Mom & Pop oscommerce/yahoo storefronts and aren’t sophisticated enough to regularly update their prices.

    Here’s a quick price sampling for the UB121100:

    * Apex $208.30

    * Apex $174.40 (huh?)

    * Apex $170.10 (different battery, re-packaging?)

    * Alt Energy $130.46

    * TSB $159.95

    * Safe Mart $154.25

    * Monster Market $168.95

    * Battery Solutions $168.95

    * Complete Battery $129.95

    * Powerhouse Battery $97.16

    * Or just Froogle it

    Still, as you allude, eventually I’ll have to get off the pot and do something. I can buy the Hawkers for $236 (perhaps slightly cheaper) from a place within driving distance. Or I can spend another week trying to find something cheaper, and then find a place nearby that will sell them or an online store that doesn’t have outrageous shipping fees.

    From my research it seems that the going rate for a quality 100aH AGM is about $170-$190. Is the extra $50+ bucks for the Hawker worth it? Dunno.

    This calculator grew out of my frustration from trying to compare batteries and because I thought it might be useful to others in the same situation. You know, "here's my general EV setup what kind of range & overall weight will this battery have?"

  9. — John Westlund    Jun 21, 2006 09:53 AM    #

    Yeah, that $85 is what Cor Van De Water(I think, may have been someone else) got them for on a discount by buying a large amount at once. I think that included shipping, but I’m not 100% sure.

    Prices for batteries vary widely. Some distributors will rip you off. I’ve seen prices for Trojan T105s ranging from $70 to $180, with the price on the lower end even having been recently updated with these lead price increases. Same with the Exide Orbitals.

    If you have very severe reservations, it may pay off to buy one or two batteries for testing purposes, provided you have something to load them with. This could help you find the cycle life, internal resistance, and capacity versus draw data you’re looking for.

    Manufacturer’s specs should be taken with a grain of salt. Personal anecdotes are much better, provided they are backed up with numbers. But nothing will ever match your own experiences. The only downside with this is getting that ‘experience’ requires your hard earned dollar and some time. I’m so glad Rich Rudman took data on various batteries. At 55-60 degrees and 1 hour rate, Rich Rudman got 300 Wh per Exide Orbital to 100% discharge, for instance. This is far from what you’d expect it to have with a Peukert’s calculator. Using one of those, you’d expect ~450 Wh!

    Myself? So long as it has worked for others, I’m going to pick a battery and use it. I expect to kill it anyway(so cheaper is better), but maybe I won’t. Given that there are two working examples with these cheap AGMs and given their relative low cost, I’m rather fond of the idea of using them.

    A 100AH 12V AGM is perfect for me. I originally decided on using Trojans then upgrading to Exide Orbitals, but only because I couldn’t find any large 100 AH AGMs at the time or any heap AGMs.

    A 156V pack of these large AGMs would be perfect for me. In theory, it’s a ticket to 100 miles highway range for the car I have. I’ll be happy with 1/3 of that and so expect low range by default; I’ll be very pleased if I actually obtain results close to theory.

  10. — Ed Cochran    Jun 21, 2006 11:53 AM    #

    800 pounds of batteries equals a galon of gas? I assume that the person was talking about a conversion done with a dc motor with lead acid batteries. My question is if the motor was a-c would the batteries take you farther?

  11. — JAMES    Jun 21, 2006 12:16 PM    #

    Has anyone looked into the new M1 batteries from A123 systems?
    I heard everything electrical will be revolutionized.
    5 times the peak power, with a charge time of 5 minutes for 90% charge.
    they are lighter, i think it will reduce battery wieght in hybrids buy 80 pounds.
    if someone has heard of it please let me know @

    thnx james

  12. — John Westlund    Jun 21, 2006 20:51 PM    #

    Ed, an AC motor and inverter will give you roughly 10% more range than a comparable DC system with the same battery setup. Most of this range gain is due to regen.

    An AC motor and inverter is only slightly more efficient than a DC motor and controller. The AC’s real benefit to vehicle efficiency is in regen.

    Given that this ‘rule of thumb’ has a large margin of error(although accurate enough to have use), whether the conversion is AC or Dc won’t make much of a difference.

  13. — John Jackson    Jun 21, 2006 21:25 PM    #

    Kert and James,
    I disassembled one of the Dewalt battery packs Monday night. Here is what I found.
    1.There are 10 of the M1(18650 formfactor) cells installed.
    2. There is a built-in BMS that is potted and mounted to what appears to be an aluminum plate.
    3. Unless I have two bad batteries(brand new and fully charged. The actual output voltage is only 34V. This makes sense if the specs page you listed at seattleeva is correct. 10×3.3V=33V. I had naively guessed that there would be 11 cells in the pack.
    4. There also appears to be a temperature sensor taped between the battery pack and the BMS.

    If you keep your eyes open on Ebay you can probably get a decent deal. I purchased the entire hammerdrill set for $300 including shipping. That set came with two batteries the charger and the drill. Most places are selling the batteries at $149-159 each. $90 for the charger.

    I haven’t load tested them yet. And it will likely be a few weeks til I get to that point.

    Dewalts specs say that this drill is capable of up to 750W at the working end of the drill. Assuming at least a 5% mechanical loss from battery to drill tip gives about 790W which translates to approximately a 23A current flow.

    Also will keep a log of number of charges as these are supposed to be capable of a 2000 charge life cycle.
    Good luck,

  14. — John Jackson    Jun 21, 2006 21:35 PM    #

    Also, I have seen the Dewalt battery(DC9360) as low as $119.00 on Ebay.

  15. — kert    Jun 22, 2006 03:38 AM    #

    You did see the page at SeattleEVA with Milwaukee/eMoli battery pack data right ?

    What i’d like to know most is whether deWalt cells live up to A123 claims of 5 min recharge capability, and of course the life cycle too

    Plus, when i get my hands on those i will make a overcharge test in my backyard, just to see whether they really are as safe as they claim

  16. — kert    Jun 22, 2006 03:54 AM    #

    btw, for easy price check, type in the product no into froogle and sort by lowest price


    i get ~$150 for deWalt, and ~$110 for Milwaukee.
    Bosh 36V 2Ah lithium batteries [2607336004 part no] sell for around $260 in UK..

  17. Jerry Halstead    Jun 22, 2006 07:41 AM    #

    I got an email from Cor regarding the UB121100 batteries. He’s had them since January (3,000 miles) and is very happy with them so far. He was able to confirm the 80A at the 1 hour rate (110aH at C20). One caveat is that he runs a higher voltage AC system and doesn’t need to pull more than 200 amps from the batts.

    The other person is Mark with 12 of the batts in his Geo Metro. He said there’s a slight smell of acid during discharging, and that the terminals seemed to move rather easily during tightening (most likely related). He has 350 miles on them so far, longest trip 22 miles. He dialed his controller back to keep peak amps less than 225.

    I contacted the folks with the lowest price ($97) online, powerhousebattery.com and they are back ordered around 6-10 weeks. They ship out of Texas, so add another $130-$170 for that (not sure if that’s for a full pack’s worth).

    They look interesting. Over half the price of the hawkers, which have a 4 year warranty. Cor said his dealer promised to replace any UB121100 that dies or loses 20% capacity in a year.

    Will have to look around and see if anyone has them in stock, or at the $85 price anymore.

  18. — Ed Cochran    Jun 22, 2006 12:55 PM    #

    The problem i have so far with converting a car to electric is the range. I drive 30 miles one way to work so i need a car that will get a minimum of 75 to a 100 miles in range. Florida is flat as a pnacake. The only batteries that can do that is Lithium Ion or gel. I have figured out how I am going to do it now I need to wait for the prices to drop. My research has shown that I can get the range and voltage from 13 Valences U26 batteries but what is the warranty on them?

  19. — John Westlund    Jun 23, 2006 01:06 AM    #

    Actually, you can get that 75-100 miles per charge or even far more than that with cheap flooded lead acid batteries, if you have the right vehicle.

    A small pickup loaded with 2,000+ lbs of batteries can do 120 miles at highway speeds on flat ground. This is without aerodynamic modifications, which would surely extend range more.



    Brian Methany posted on someone’s EV World blog that his battery pack lasted ~50,000 miles. That post is no longer on EV World. But his truck is a good example of how to do a long range EV.

    John Wayland made a 450 mile round trip from Portland, Oregon, to Seattle, Washington, and back in an electric pickup. Not on one charge, mind you, but the vehicle was still practical enough to do it.

  20. — Ed Cochran    Jun 23, 2006 14:49 PM    #

    What I intend to do.

    Yes I know that people can go over a hundred miles on lead acid when they put them in a small pickup. I have a family of 4 with the only pickup that would work being a crew cab but the bodeies of thoes are expensive. What i want to convert will be a Nissan Sentra 2000 or later model year. Take the spare tire out and weld the floor flat. Placing the batteries under the trunk. I also want to use a automatic transmision with a a-c motor. The reason for this is they are programable. What i have figured out is to have 2 pediometers controling the motor instead of 1.

    Here is how it would go.
    THe pediometers would be instaled on the gas and brake pedals. when the car is not in motion and th brake pedal is depressed the motor stops.
    When the car is stopped and the person releases the brake pedal the motor starts reving at 500 rpm.
    when the person depresses the gas pedal the car drives normal.
    While the car is in motion if the person pushes the rake pedal the regen is turned on until stopped then the motor stops.

    Being a computer programmer I beleive i can accomplish this. THis will in return make a very efficiant car with no shifting required while driving. While giving the transmision time to get the fluids going before going.

    Why A-C not D-C ac is more programable then dc and more importantly dc motors have alot of torque when they start where as ac motors do not. A dc motor would probably tear up the transmision where as an ac would not.

  21. — James May    Jun 23, 2006 15:36 PM    #

    Hi Ed. Nissans are good and light but auto boxes are not very efficient I think, unless yours doesn’t use a torque converter. It all sounds a bit complicated as well. Good luck though!

  22. — Ed Cochran    Jun 23, 2006 17:30 PM    #

    It will use a torque converter. Sot that the transmision will act the same as stock. Using the same fly wheel as stock ICE motor. The fly wheel will be modified to have a male adapter to fit into the ac motor.

    The assembly will require 3 parts to be custom made the motor mounts to chassie, the transmision plate to mount the motor on the transmision case. the male shaft to be bolted onto the flywheel.

    It would be assembled by taking the flywheel and bloting it on with the male adapter, then placing the transmision plate on. What you will have after that will be 4 bolts sticking out for the motor and the shaft going to the torque converter. then i would mount the chassie motor mounts. THen the motor should be able to be installed easily.

    This way i have a more efficiant car for high speed travel.

    What did you mean by the auto boxes are not efficiant? Please explain.

  23. — John Westlund    Jun 23, 2006 18:51 PM    #

    A Mazda B2000 pickup with crew cab could be had for relatively cheap.

    Getting 75 miles in a Sentra will not be easy! You’ll definately need to do aerodynamic modifications for that, which will alter the vehicle’s appearance. GVWR will be a big concern: you’re looking at a minimum of 1,200 pounds of lead acid batteries, whether AGM, Gel, or flooded.

    And that 75 miles will be to about 100% battery discharge. Doing this regularly will result in a very short battery pack life, and you’ll usually want to keep the percentage discharge to 80% at the most, preferably under 50%.

  24. — JohnG    Jun 24, 2006 11:44 AM    #

    We have discovered with the Elec-Trak tractors using 36V of “T105” style true “Deep Cycle” battereis that the BMS can easily extend the life of flooded packs by a factor of between 2 and 2.5. This is true even when the charge currents are FAR below the standard suggested levels.

    There are a number of people who have replaced the factory ferroresonant chargers with small “Soleil” 36V 9A(3 12v/3A banks) chargers and have seen 7+ years on a pack. With the factory charger (36V 12-17A), few people can eek out even 4 years on a fresh pack. I am on my second year of using a 3 bank MinnKota 30A (three 12V x 10A banks) charger, and there is no detectable loss in capacity. I use my tractor all year, and the highest loads are in the winter blowing snow.

    The quality of the charge and DOD during operation have the largest affect on pack life.

    You are FAR better off to use a single high voltage lower amperage string, than two or three lower voltage strings at higher amperages.

    Yes, I believe the 800# = 1 gallon gasoline generalization.

    An automatic trans will NOT work in an EV unless you “idle” the motor while stopped, and this will very significantly reduce range. The reason is that the AT works on hydraulic pressure, and with the motor off, there is no pressure to engage gears. It will take a second or so to build pressure after you depress the accelerator and the motor starts to spin.

  25. — kert    Jun 25, 2006 11:47 AM    #

    regarding AC motor not having torque..

    With vector control AC motors can have constant torque over a 1:1000 RPM range, meaning that with proper inverter rated motor you can pull the same torque basically at start as over 15000 RPM.

    There are off the shelf industrial programmable inverters that can do that but their featureset is not very suitable for EV.

  26. — Ed Cochran    Jun 25, 2006 16:40 PM    #

    THat is why you need first gear in the automatic transmision so that you can use a smaller motor

  27. — Nick Smith    Jun 26, 2006 23:14 PM    #

    Why do you particularly want to use an auto transmission? To answer your previous question they are inefficient due to the fact that the torque converter is basically an hydraulic coupling – there is no direct link – and therefore the motor is always driving faster than the gearbox, a phenomenon I refer to as ‘slip’. Granted, modern gearboxes do have ‘lockup’ converters that do direct link once the ‘slip’ reaches a minimal figure. For the most part you are just burning amps to pressurise the fluid in the transmission. Have a look on “howstuffworks” dot com and search for auto transmission.

    In a manual gearbox you have a direct link full time through the existing clutch which, one you have put it in gear or changed gear between highway and urban speed ranges, you never need to use. The car will drive ‘just’ like an auto as you don’t have to take it out of gear or depress the clutch to stop the car.

    What you intend to do with the motor controller seems ambitious seeing as how you can just buy the Siemens controller from Metric Mind with all this stuff built in – it is expensive though.

  28. — Ed Cochran    Jun 27, 2006 10:06 AM    #

    The Slip in the new auto tranmisions is minimal.

    In an automatic transmsion you do not need to shift gears so you can use all of the gears. most people just use second gear in there electric cars.

    The person who owns metric mind did not use a pedio meter in the brake pedal for regen he used a switch. his conversion was one of the best I have read about.

    If I used a carro gear box instead of the auto transmsion the electric motor would loose the efficiancy at high speed.

    My wife can not drive stick and said she would only drive a conversion that has automatic.

  29. — Christopher    Jul 05, 2006 05:20 AM    #

    Is the Etek motor the suspect motor? Because I can get rediculous mileage on that thing.

  30. — Dan    Jul 06, 2006 09:19 AM    #

    Altair Nanotechnologies Teams with Phoenix Motorcars and Boshart Engineering to Test EVs

    The current production plan is for 10 vehicles by the end of 2006 (in process), 500 vehicles in 2007, 5,000 in 2008, 20,000 in 2009, 50,000 in 2010 and 100,000 in 2011. Initial pricing is in the low to mid $40K range.

    Heck, I’d be amazed if just one of the hyped-up Li-ion battery makers would just make a usable product for EV consumers.

  31. — Dan P    Jul 10, 2006 23:54 PM    #

    Hey Jerry,

    I’ve been following along in my minds eye of your exploits and as a retired auto tech / shop owner it brings back fond memories of some projects that I was involved in over the years.

    Enter the “CARUCK”; a Nissan Hard Body whose body wasn’t so hard after the salt of Maine got a hold of it and a Datsun 310GX hatchback with a blown engine. With a chop and shortening of the truck frame and rear drive shaft using the most high-tech of craftsman tape measures (yellow button in the center, chrome peeling off the plastic case), some hockey pucks as body mounts, modified gas tack location and a line lock on the brakes main line to replace the parking brake cables gives you a Stomper of a 4X4 with two front bumpers.

    I wish I had found your page sooner before you had to pay homage to the knuckle gods so I could have suggested just dropping the whole drive train out the bottom then split the engine from the transmission.
    It sure is faster and easer that way to work on.

    But today I get to read more on your battery musing and would like to expand on a quick and dirty testing of battery choices.

    First off I never believe the numbers the sales man offers for their product and as was stated no two batteries are the same.

    The questions you seek to answer are how will it hold up under constant use & abuse in real life.
    This requires a test vehicle of sorts.

    Since I am not one for running out and buying a lot of electronic gear for computing peukert’s law http://en.wikipedia.org/wiki/Peukert’s_Law yeah I looked it up, I envision a simple construct to be used as a test bed.

    The use of an exercise bike with a tension wheel and a speedometer/tripometer on it should work fine. You should be able to find a few of these in yard sales all around town or just laying at curb side and usually like new.
    Reconfigure the chain drive from the peddles to an electric motor, it dosn’t have to be pretty, it just has to work so keep the peddles and add some links to the chain. The motor can be DC or AC with an inverter because it really doesn’t mater; your testing the battery not the motor.
    With the tension wheel you can set an average resistance, that of the roads you normaly travel for this of course you get to ride a bicycle up and down your road a few times just to get that feel for setting the tension pully. Now using those formulas out there you could figure out what the motors rpm is and with a multimeter you can get the amps being drawn off of the battery; don’t forget to check your clock for accurate longevity.

    This is my ruff idea of putting your battery choices to the test. Just buy a couple of your top picks and put them through their paces. You can drain them down to 50% recharging one while testing the other, rinse and repeat. A week of hard abuse should tell you which one has the stamina for you.

    Dan P

  32. Jerry Halstead    Jul 19, 2006 07:03 AM    #

    Howdy Dan,

    Yeah, I wish you would have showed up earlier with the dropping the engine idea, too! ’:^)

    What some folks do for a test bed is to use a bunch of light bulbs. You can get some high intensity outdoor bulbs that really suck down the watts. Since they are resistive loads it is easier to set up a rig which will have a constant current draw.

    Considering that incandescent light bulbs turn more of the energy into heat (about 95%) than they do light, you’d be best served conducting these kinds of tests in the winter!

    Hmm, maybe an air conditioner could be rigged up as a load in the summer?

    I’ve actually considered buying some sample batteries and doing test “reviews” of them. Do I go the consumer reports route and buy them myself, or do like most magazines and request free review models?

    The other question is one of statistics. Can you really get reliable numbers by testing only one battery per model? Or should you test at least two to rule out anomalies?

  33. — Brent    Jul 20, 2006 18:19 PM    #

    I’ve been eagerly awaiting your final masterpiece, as I’ve been debating on if i should create my own. As this link demonstrates, Sometimes good things come to those who wait (and can afford it as I’m sure I can’t :) )I’m sure you all have seen it, but, how fun would it be to own it? In my opinion, it would entice even the most anti EV owner to try…


  34. — Brent    Jul 20, 2006 18:27 PM    #

    Oh, I suppose I should tell those who don’t know, Tesla motor company is a new EV car company based out of California in Silicone Valley. The company just barely released it’s first car due for sale in spring of next year. It is a 2 seat roadster 0-60 in 3.9 seconds with a 250 mile range. The body was designed by Lotus, and is built in the Lotus plant in England.

    It got my attention….

  35. Donald Bohn    Aug 04, 2006 10:37 AM    #

    I’m very impressed with your hands-on, non-political (no hate) approach to EV’s. Here’s a letter I got from DC Batteries in FLA.; For domestic Renewable Energy applications we move more Surrette volume then any other type. You can review the Rolls and Surrette solar line at http://www.dcbattery.com/rollssurrettesolar.html

    The Lifeline has been used to a lesser extent in domestic solar but rather heavily in EV’s where non gassing non-spillable batteries are preferred. In 2006 the lifeline has been challenged by the Fullriver in mobile applications. You can review the Fullriver Battery line at http://www.dcbattery.com/fullriver.html The Fullriver offers more capacity at far less cost.

    I would review the FRGC2 for the applications above as their cost per weight/capacity are excellent.

    A Lifelline Lgc4 is$187.86 in modest orders while the FRGC2 is $119.12

    All of the above are in our inventory.

    Hope this helps.

    Dave, the BatteryGuy

    Pretty cool, huh?

  36. — vic pretti    Aug 11, 2006 02:06 AM    #

    hawkers are a different animal they maintain amp hour capacity better at high currents and a 75 ah hawker will outperform any other 100 ah battery i have seen in an ev they last a long time and can be charged very fast 45 minutes but can be damaged by overcharging

  37. — Dave    Aug 11, 2006 10:29 AM    #

    I’m new to your blog and have a few questions/comments. First of all why is there a need for a transmission in a rear wheel drive car anyway. If my calculations are correct(yeah right) a motor turning at 5000rpm connected to a 3.89 rear end and 13 inch tires should give 86-90mph depending on tire type. What am I missing?

    Also I’m going to be converting a Triumph Spitfire, since I have a few in the yard( I’m not really a redneck, just a yankee living inexile in Florida)and I have quite a bit of knowledge about them. Lastly, if there is anyone out there that is in North Florida/South Georgia who is into EV’s let me know. My email address is triumfan@comcast.net
  38. — larry    Aug 12, 2006 01:40 AM    #

    Great site… lots of info and insight. Curious if you had any email exchange with Thunder Sky regarding their higher capacity batteries… 200 or 400Ah for instance. I realize that you don’t require much range for your application but many others (myself included) need upwards of 60-70 miles for a real useful conversion(it’s cheaper to buy more expensive batteries than to move closer to work… in Denver anyway). Seems that a 142.8v 400Ah pack would deliver awesome range and still be lighter than a conversion with lead acid. But, i haven’t received a response from T-Sky yet with price and delivery info. It may be cheaper to buy a new house… any input?

  39. Lloyd    Aug 12, 2006 11:11 AM    #


    I’m considering doing a conversion on a 1990 Honda Civic SI. I wanted to run several of the conclusions of my research thusfar across the group and make sure that I’m understanding things correctly.

    1) The total combined voltage of all your batteries should equal the maximum for your motor. What happens if you go over?

    2) I’ll probably have to improve the suspension on my vehicle to hold up all that weight.

    3) Everyone wants lithium polymer batteries but no one seems to be (interested in) delivering an effective solution.


  40. — Tom    Aug 13, 2006 17:10 PM    #

    OK this is the first time posting here so don’t flame me if I am in the wrong section. I am currently designing an EV conversion and I ran across this tidbit of info http://www.eere.energy.gov/afdc/progs/view_ind.cgi?afdc/5397/0

    I live in Virginia and I hope this doesn’t apply to all EV’s. I am imagining this only applies to golf cart type EV’s, no??

    Nice website here, keep up the good work…

  41. — Nagorak    Aug 13, 2006 23:42 PM    #

    Tom, the NEV laws don’t apply to EV conversions. The thing about NEVs is they don’t have all of the standard safety equipment required on cars. The extremely stringent safety requirements are one of the biggest barriers to entry into the car market, and it’s why commercial EVs are such slim pickings (nonexistant may be more accurate) in the United States.

    Several of the NEVs sold here are from other countries and they are easily capable of going 40 MPH, but they are artificially castrated to not allow them to go faster than 25 MPH in order to meet the NEV requirements. It is one of the most infuriating things, as a non-highway vehicle clearly does not need the same level of safety features. But the NEV mandate sets the speed too low to be even practical for use. If NEVs could go even 35 MPH they would be practical, as they could then travel on streets posted up to 45 MPH (10 miles over the speed limit).

    At 25 MPH NEVs can only go onto streets up to 35 MPH, which renders them useless in almost any urban area as you often can’t get from point A to point B without traversing at least one 40+ MPH street. Then on the streets you can legally go on, the slowness of NEVs is more of a danger to the driver, than if they could go a little faster, as all the other cars aroung will be going faster and they will frantically try to get around you (who even follows the posted limits on streets, and you’ll be going 10 MPH below the posted limit!).

    The whole law surrounding NEVs is one of the most backward and unnecessarily restrictive vehicle laws on the books. The fact that exceptions for safety equipment are not extended up to a reasonable speed means that a cheap, low speed EV is basically an impossibility. The only way to get around it is to do what Zap! did, and build a car with only 3 wheels so it counts as a moped, because it’s totally fine to risk your life on a motorcycle or moped, but as soon as you build a car it has to meet the utmost safety standards. This is why some people believe that the whole inadequate NEV classification was a thinly veiled attempt to stamp out EV development.

    Fortunately, with a conversion none of that applies as you’re driving a vehicle that is already up to the safety standards required. :)

  42. — Nick    Aug 14, 2006 04:14 AM    #

    to Larry

    I have recently contacted Evergreen (thundersky) in Honk Kong about the larger capacity batteries. Their response was basically that the larger sizes are not commercially available but after some pushing they said that they would sell me them if I wanted to be a ‘guinea pig’ – which I took to mean “no warranty”. Pricing was not too horrific (if you only wanted one or two :^ ).

    I have read a few posts (don’t ask me where – I think Jerry may remember) that had quite negative comments about the batteries, the company, and the support – so let me know how they work out!

  43. — James May    Aug 14, 2006 14:32 PM    #

    Hi Nagorak, I have just been reading your comments on www.theoildrum.com I guess we both like the same sites. I am only brave enough to post here though! To quote from Bob Dylan’s “Hard Rain” I like to know my song well before I start singing! i.e. I don’t feel expert enough yet.

  44. — Tom    Aug 15, 2006 16:04 PM    #

    Thanks for the info on NEV’s. I have never heard of these before but they sound fairly useless to me.
    Also as a side note, I am at the point of frustration with battery choices as many EV builders are however, it looks as though something good might be available to us by the end of next year. In the meantime, I am deciding on a propulsion motor and controller. I really want to go with A/C with a voltage in the 300 to 400 range. I am leaning toward something from MetricMind likely using a Siemens motor & controller. The doner is a WV dune buggy. Extremely light weight but not a good choice for large battery placement. However, considering the large ground clearance, if I find batteries that are less that 5 inches tall (or thick) I think I can build a battery box that slides underneath the floor pan. This would provide a lower center of gravity. My first goal is performance and second is range. I am wanting to get 0-60 accell time to under 5 seconds which shouldn’t that hard to do if I can keep teh battery pack under 1000 lbs. Anyway, it looks like I will be waiting untill next year to decide on batteries…

    Again, thanks for all the info.

    Oh yeah, I also ran across a another tidbit on Virginia rules that says EV’s must pay a $50 annual fee to compensate for gasoline taxes…

    Have fun,

  45. — Nagorak    Aug 18, 2006 00:15 AM    #

    Hi James. Nice to see others travelling in the same circles. Hopefully nothing I’ve said at the oildrum is too stupid. :) It’s an interesting site, but some of the really pessimistic posters get on my nerves. Who knows, maybe their pessimism will turn out to be right, but it’s sort of frustrating when you’re trying to learn how to convert your car to EV, and actually trying to do something to make a difference, only to see others who want to proclaim the end of the world. Other than that there seem to be quite a few smart guys over there who know their stuff.

    Tom, good luck on your conversion. I am in the process of learning how to convert my car to EV as well. Still in the early planning/information gathering stages, but I definitely am set on doing it. That’s too bad about the VA annual fee. Seems kind of petty, especially since you probably have taxes and/or surcharges on your electricity already.

  46. — Tom    Aug 18, 2006 11:18 AM    #


    Glad to see so many people out there doing the same thing. This is exciting work for all of us I am sure.

    I have been wrestling with calculations concerning range and performance. It’s confusing considering so many unknowns with respect to rolling resistance, wind resistance, aerodynamics, etc. This morning a new idea popped into my little brain. Why not calculate backwards using known data? So, I set up a spreadsheet that takes the energy content of gasoline in BTU’s, converts that to watt/hours in a one hour burn period, HP over a one hour burn period, etc… Ultimately, I can input the measured MPG of a test car at 60 MPH and with an estimated efficiency of the gasoline engine (15% to 20% typical) and have displayed the watts/mile at 60 MPH. Of course there a few assumptions as in any calculations such as ICE efficiency, and that the energy content of gasoline.

    The net results are thus: Assuming an ICE efficiency of 18% and a gasoline energy value of 115500 BTU/gal, For a car that gets 30 MPG at 60 MPH as an average, will need about 203 Wh/mile as a motive force. This does not include inefficiency in the electric system. Further a car that gets 60 MPG at 60 MPH will require about 102 Wh/mile and a car that gets 15 MPG at 60 MPH will require about 406 Wh/Mile.

    Now while my math skills and energy engineering knowledge are not the best in the world, I ask the experts here if they feel that this is a valid calculation. What do you all think??

    Thanks for any input.


  47. — Nagorak    Aug 18, 2006 22:30 PM    #

    That’s an interesting idea, but it might be to account for variations due to varying engine efficiency. For example, a car with a 6 cylinder engine will generally get much worse gas mileage, than that same car with a 4 cylinder engine. The 6 cyl has more “power”, but most of the time it’s unneeded and the larger engine will operate less efficiently due to the unneeded extra cylinders. It seems like you’d need to know the exact efficiency of the specific engine to really get an accurate picture. Of course, any hybrid type setups would obviously mess up the calculation.

    Another thing to consider is the impact of the extra weight being carried around as a result of the batteries. It seems like that extra weight would have an adverse impact on the amount of watthours/mile.

    I guess, I’m sort of leaning towards the somewhat crude, “max out what the vehicle can carry” and then find out how far it will go. I’m sure I will do some rough calculations, but there are so many variables that I’m not sure it’s worth trying to calculate it down to the exact inch of range. My hope is just to use fairly inexpensive flooded Lead Acid for now, and hope that 5-10 years down the road better battery technology will be mainstream so I can retrofit for better range/weight.

  48. — James May    Aug 19, 2006 09:03 AM    #

    Hi Nagorak,

    my EV is as you describe, full of flooded lead acids for range, it’s also on this site under “conversions”. one of the downsides of changing battery technologies is that you have to fork out for an expensive new charger and maybe some other bits and pieces. Also got to fiddle with all the mountings again. I am vainly hoping for the lead acid firefly technology to become available when my pack of golf cart batteries wear out. Hoping for a drop in replacement. Now, there’s optimistic! BTW I am a fraud and didn’t build mine from scratch, I bought it and rebatteried it.
  49. — Tom    Aug 19, 2006 10:48 AM    #

    You are of course correct that my calc does not take into account the added weight of batteries and the ICE effiency is only a guess but, comparing the ICE eff range from .15 to .25 gives me a good starting point. I really do not expect to be exact as there are other variables such as driving style, wind, terrain, etc. But, the numbers I have seen are similar to the numbers displayed in the EV Calculator on this site. So, I feel comfortable that I am in the ballpark. I just wanted to make sure that I don’t finish my project and find that my car only makes it to the end of the block, depleting the batteries over a one mile range. I now feel confident that I can get to town and back with much smaller batteries than I had originally thought.

    I also have resigned myself to lead acid for now however, I can’t stomach using flooded batts. While I have never built an EV, I have been using flooded batts here for backup power for ham radios for quite a while now. They are OK but are messy even in stationary usage. I switched to AGM on one of my repeaters about a year ago and like that much better than flooded. But AGM comes with it’s drawbacks too. I like the looks of the EaglePicher Horizon 12D2000 but I still end up with more weight than I wanted for the range I would like. One other thing I noticed about batts has to do with cycle life. The general rule is more DOD results in lower cycle life (of course) but more DOD results in more KWh per charge. Bottom line is it seems to me that battery life is more attuned KWh throughput than to DOD only. In other words, take two identical EV’s, drive one through it’s battery life recharging only at 50% DOD and the other with 80% DOD. In the end of the battery cycle life, , which one traveled more miles? I am willing to bet that they will both be very similar, but just my guess. I haven’t calculated this closely yet but soon will take a closer look at it. This will also depend on the specific battery of course. Lots of people say there is no free lunch and I hate that because I live on free lunches :)...

    James, you aren’t really a fraud. You have an EV already and I don’t think it matters how you attained it.

    Anyway, my finished project is still two years out there so maybe we will have some new battery alternatives by then. One can only hope. In the meantime, I have resigned myself to settling for a 75 mile range. I can live with that for now, but will be pushing for 100+++ as time goes on.

    Take care,


  50. — Woody    Aug 23, 2006 07:22 AM    #


    According to EV America’s liturature, the battery cycle time to DOD curve is not linear. That is I believe you get more miles(KWH)over the life of the batteries with deaper discharges. (Fewer cycles but disproportionally more miles) I don’t know from experience if it’s true. I’m on my first pack. I tend to charge at about 50% discharge or less. Mainly because I’m always afraid I’ll want to use the car for a 30 mile trip and only have about 10 left.

  51. — Tom    Aug 23, 2006 17:21 PM    #

    I am not surprised Woody. But if this is the case, I wonder why so many seem hung up on keeping DOD light such as 50% or less, especially when calculating effective range. If more total miles can be obtained with 80% DOD, why not consider 80% DOD normal effective range? Or am I just misinterpreting things here?

  52. — Woody    Aug 24, 2006 08:11 AM    #

    Apart from the inconvenience of needing the 30 mile trip with only 10 left in the pack; I think there is some danger to the battery life in the deeper discharges. If an individual cell is lower than pack it could cause damage (One cell may be at 100% when the average is at 80%. (This is why it’s important to ocassionally monitor individual battery voltages.) A deeply discharged pack with little activity in hot weather can contribute to sulfication and reduced life etc. Plus its good to change up the DOD to avoid creating a memory, by constantly plating the lead to the same level. The pack will then resist discharge past that point. I’m not a battery expert, so anyone please correct me or add if appropriate.

  53. — Rich    Aug 28, 2006 12:51 PM    #

    I get a great price on the Powersonic PS121000 AGMs and I can have them drop shipped to your doorstep.

  54. — Tom    Aug 28, 2006 17:28 PM    #


    Can you enlighten us? If you can’t publish the price here, can you email me a figure?
    tuhlman at kimbanet dot com.


  55. — Linn    Sep 12, 2006 00:50 AM    #

    I am new to this discussion but have some experience with odyssey (Hawker) batteries in RV use. They do not have the AH capacity of a flooded battery of the same size but they can be recharged in 1/10 the time of the flooded batteries. They also have unbelievable discharge capacities. I have seen a pair of 1200 odyssey batteries recharge to 95% in 4 HRS on a 40 amp switching converter/charger. The batteries will take as much current as you can give them as long as the voltage stays below 15 volts. I have seen a group of 1700 odyssey batteries, (3 batteries in parallel) drawing 130A in a diesel pusher motor home with a 150 amp alternator. Odyssey batteries seem to charge at high currents until about 95% and then taper off. If you could build an EV with a small generator you could use less battery capacity and have unlimited range. Fuel could be propane, alcohol, diesel or gas. Has anyone done this yet?


  56. Cor van de Water    Sep 29, 2006 01:35 AM    #

    Hi Jerry,
    I do not know if you still want input on the battery choice, I should have shared my experience with the UB121100 that I run in my truck with you already, but I get tons of email and I regularly post on the EVDL about my experiences, so here is an update:
    Today I have 4200 miles on these batteries since january this year. My truck has a good range, especially when I drive it cautiously – I have done may runs over 55 miles up to 63 on a single charge. I have one string of 26 batteries, total 312V and the current is limited to around 200A, but since the cold cranking amps are over 700, they should be able to give bursts of power to that level.
    I have no battery balancing on these batteries and I suspect that the batteries have slowly drifted a bit apart in state of charge, as I noticed the other day that I have 3 bad batteries which have lower voltage than the rest, though the performance in the string is not reduced.
    Since it is less than a year since purchase, I get 3 new batteries under warranty from UniversalPowerGroup.com
    The price is dependent on the total value of your purchase, my price of $85 was because I ordered for 3 EVs at the same time. Shipping is free above $1500, though the prices have increased a bit due to lead price increases. After Okt 1st the price will again increase 10%.
    I have been very happy with these batteries so far, though I have less than 100 full cycles on them (4200mi/63mi range) and since the manufacturer claims between 300 and 500 cycles, I count on 400×63 or around 25,000 miles before the pack will lose more than 20% range. But I will need to install battery clampers and monitors to avoid I drain some batteries too far again.
    Let me know if you have more questions,

  57. — James May    Sep 29, 2006 07:16 AM    #

    Hi Cor

    My 6v golf cart batteries are drifing out similarly after just over 100 cycles. I think they’ll be OK after equalising. I’m going to root out any low batteries this weekend and charge them seperately to bring them up. I have a homemade voltage indicator attached to 3 out of my 16 batteries so far. It’s made out of resistors and zener diodes and LEDs and is supposed to light up per battery at a little over 5v. THe idea is that you watch the lights as you load the batteries on the accelerator and the first battery/ connection light to light up shows up a weak connection or a weak or undercharged battery. It lights up too early now, just under 6V so I need to work on it.

    When it is finished I’ll be able to tell when my babies are drifing apart. I’ll also post pictures and diagrams on this site if Jerry will do one of his little articles.
    Building something like this just shows you when you’re done how much better it can be done if you thought about it more upfront. But that’s life I suppose. http://www.austinev.org/evalbum/752

  58. — me    Oct 04, 2006 21:53 PM    #

    Has anyone looked into buying the battery packs in the Toyota or Honda EVs ?

    Aren’t T105 (Golf Cart Batteries) rated at 225 AH ?

  59. Pete Hutch    Oct 04, 2006 22:16 PM    #

    I am kind of a lurker on this sight and a few others. I have kind of crossed over from the Forklift/Golf Industry and have started looking into the EV’s. I much prefer the home built vehicle over the purchased. Now to tip my hand and explain my interest. I own a company that designs and manufactures battery watering products. We primarily do Forklifts/Golf Carts. I occasionly get to read the slams against how expensive our products in our industry are and how much more volume could be achieved with a cheaper product. Fair enough, volume does lower the manufactured costs to a point. Can anyone point me toward an industry association that may have some firm numbers on EV quantities and a good magazine to subscribe to for more industry info?

    Also, I am interested in getting some lit shots of our product being used on an EV. So I am asking for any volunteers. Catch is that it must be clean and I would prefer a vehicle/battery layout that draws attention. I only want one or two vehicles, so I will be picky, but the product will be heavily discounted for anyone we choose. If anyone has any interest, email me at the address given, but remove SpAm tag. Our products can be seen at http://www.liquidprecision.com or at http://www.batterywatering.net

  60. — me    Oct 04, 2006 23:48 PM    #

    According to this page the trojan T105 batteries are 180-225 AH.

    Doesn’t that make them a lot better than the Optima batteries ?


  61. — James May    Oct 05, 2006 08:24 AM    #

    Hi me. I think the Optima batteries have lower internal resistance which is good. I am usig Trojan T6220s which are similar to T105s though perhaps not quite as good. THe golf batteries, I think offer the best performance to cost ratio for an inexpensive EV conversion. Optimas suit performance EVs better.

    Hi Pete. If you look on EV album you can see just what proportion of EVs use flooded batteries. I’d like a watering system myself because I’m tired of watering them manually. Cost has stopped me so far, also harder to find them here in England and they tend to be even more expensive.

  62. — Mark Jeffers    Oct 09, 2006 21:29 PM    #

    A question about hawker batteries.

    I use a handicap scooter that uses U1 batteries. I need to know if Hawkers live up to their hype. I’m thinking about ether their 2V cells in gangs {my controller can take up to 36V} Or two 12V. I’ve tried Gells, AGM, wet cells, U1 and 22NF. Had a couple of Walmart trolling batts, they worked great but were just to heavy for my scooter. Thanks for your help, I read this site all the time and dream. Thanks, Mark

  63. — A. Pirocchi    Oct 10, 2006 00:33 AM    #

    Hi Jim,
    Great series and love the posts.
    Any more info on Firefly Energy’s carbon foam and graphite foam core for lead acid batteries??? It also may remedy EV weight and distance restraints.

  64. — James May    Oct 10, 2006 07:21 AM    #

    Hi Mr Pirocchi.

    No more news I think! I look periodically. I think we are all waiting for them. Achingly!

    Mark Jeffers.

    If you look on John Wayland’s ste, he thinks Hawkers in any size are unbeatable for robustness and current delivery. http://www.plasmaboyracing.com/blog/?m=200604

  65. — David Anderson    Oct 26, 2006 00:01 AM    #

    I am a high school Auto Technology Instructor. Last year my students and I took a VW chassis used an aircraft starter generator shunt type motor. with a 48 volt battery pack. using a curtis controler. I want to put a gen set on it to make it a series hybrid. My question is will the controler be adversly affected by doing this. My expierience is limited. I have tried to get an answer on this and no one has given any info as of yet. is anyone willing to advise, this is an expierimental endevor for teaching purposes only and will never see the open road. I would like to use it as a test bed to try different alternative fuels. I realize it is not going to be high efficency. each year I plan on up grading and making changes as budget allows.

  66. — James May    Oct 26, 2006 08:05 AM    #

    I suppose that not exceeding the maximum voltage of the controller is important. I know people have broken Zapi H2 controllers by running them overvoltage accidentally whilst charging from the charger.

  67. — JohnG    Dec 09, 2006 16:29 PM    #

    Good day Jerry and others,

    It has been a long time since I last posted on this WebLog, man I wish I had more time for EV stuff…...

    Range IS (closely) related to weight of LEAD in the pack. Batteries with the same “rating” but more lead will go further, and last longer, than lighter ones with similar ratings.

    The question was posed by Tom and others about DOD vs range vs pack life. This is VERY complicated, because of the variables, all of which are critical to each desired result.

    It is true that for most battery SYSTEMS it is better to operate them to far below 50% DOD then to recharge before that (opportunity charge). There are some VERY significant limits to that statement that are often excluded from the discussion:

    1) This assumes the system uses “batch charging” – all batteries in a string are charged from the ends.

    2) There is no “equalizer” used on any battery, and you do not have a “smart” charger.

    3) There ARE multiple unique batteries in the system (not one combined large one).

    4) The charging is at high enough amperage to equalize the pack at every charge cycle.

    The moment any one of those criteria are no longer true, opportunity charging of the pack is a HUGE benefit to pack life. So, you NEVER EVER want to “equalize” an AGM/dry cell pack, so now opportunity charging is better.

    Furthermore, it is far better to “undercharge” a pack in terms of current, and to keep it fully charged, than to allow a partially discharged pack to sit in that condition. That causes sulfation and KILLS the cells.

    We have seen (in the Elec-Trak world) that multiple chargers with very small charge currents, but GOOD voltage controls and 3 or 4 step charging will MORE than double pack life over bulk/batch charging alone. Many Elec-Trak owners use “Soleil” chargers, 3 bank @ 12V/bank – 36V total. I use a MinnKota charger made for trolling motors, this is 8x more expensive than the soleil solution, but provides 6x the chargeing amps. At this point, it is pretty hard to justify “boutique” battery solutions.

    A single string of batteries is MUCH better than two parallel strings. While you can have better control of charging two strings, you have NO control over the discharging of them.

    It is beneficial to use a single high voltage (288V+) string of 12V batteries instead of a single lower voltage string with 6V batteries. This is because the I^2 losses are reduced to 1/4 of those in a lower voltage (144V of 6V) string. Same number of batteries, longer life and more range.

    The pack amps in or out, is dependant on the pack type. PbNa “wet” types, can take a LOT of out amps, and initially a lot of “in” amps. This all changes as the SOC increases. If you use cheap chargers, you will kill the pack. With Gel/Dry batteries, some offer very good discharge and recharge rates, but are FAR less forgiving of anything over current. In fact, many Gel/Starved/Dry cell batteries are simply murdered by 120% rated amps. So you need good discharge/recharge controls.

    Enter the multiple chargers. If you have 20 12V batteries, they will not supply the same amps as 20 6V batteries, but they do not want as many charging amps either. There are any number of ways to accomplish this: 5 “4 bank” 12V (48V total) chargers, 10 “2 bank” 12V (24V total) chargers, or 20 12V “smart chargers”. Of these options, any time you charge EACH BATTERY individually based upon it’s own needs, you will significantly increase pack life and range because each battery will be recharged to 100% at every charge.

    My point? If you are spending the $$$$.$$ on a sealed Gel/Starved/Dry battery pack, you sould definately also spend the $$ on a SINGLE dedicated charger for each battery, or you should just use the “cheap” wet ones and replace as needed. No single charger can ensure each battery in ANY string is PROPERLY recharged to 100% each time. To ensure PROPER charging of every battery in a string you need a BMS, that alone will solve most, if not all, of the range/cost/life issues.

  68. jerry Halstead    Dec 12, 2006 08:28 AM    #

    Hi John, good to hear from you and thanks for the write-up and information.

  69. tim c    Dec 12, 2006 20:38 PM    #

    hi i am building a 97 saturn 156 volt pack 1200 amp raptor warp 9 motor .13 12 v agm batts .just ordered the raptor from kta .trans ap.ordered today .motor will be here in a few more days .http://www.affordablemobilityoh.com/

  70. — Justin    Jan 23, 2007 23:57 PM    #

    Just to tease you, here’s an interesting development in Ultra Capacitor technology that should do away with regular pack changes once and for all.


    The quote that gets me all excited is “will dramatically outperform the best lithium-ion batteries on the market in terms of energy density, price, charge time, and safety. Pound for pound, it will also pack 10 times the punch of lead-acid batteries at half the cost and without the need for toxic materials or chemicals”

    The days of reconfiguring your battery boxes every 4 years are numbered!

  71. — James May    Jan 24, 2007 09:03 AM    #

    We can only hope that one of these new battery technologies makes it to market without:

    a. technical difficulties
    b. being reserved for military use.
    c. being withheld by the patent owners

    If the batteries live up to their potential, they will be a “disruptive technology” i.e. there will be many applications where they out-compete existing power sources/storage.

  72. — Gene K.    Mar 07, 2007 02:00 AM    #

    Hello All,
    Let me start by saying this is my first post to this site.
    I have been looking to the EV world for 8 months now, as gas prices have begun to rise. Current prices in Metro Detroit are currently about $2.50 per gallon.
    I have noticed that most are using DC motors, I am looking at the AC option, primarily the Solectra AC24 with a 5 speed manual transmission. I know that my wife cannot drive a manual, without more clutch replacements than battery packs, thats why I am looking at AC. There is no clutch roll out. I say that because Solectra has a direct drive gear box for their AC24, therefore I assume (I know that’s a bad thing) the only time a clutch needs to be used is for a gear change. I have been basing everything off of the Voltsporsche AC 914, with flooded batteries, Deka’s won’t give me the range I need, although I would like not having the maintainance. I drive 50 Mi round trip to/from work each day. MY biggest concern is winter driving, as it can get pretty cold here. Currently I have not comitted to any body style, although 4 seats would be nice. My curent considerations are a 95 Probe, but a 914 or a Kitcar are not out of the realm.
    I just thought I would weigh in to let everyone know I am out here too.
    Thanks for the great web site!!

  73. — Charles    Mar 08, 2007 23:11 PM    #

    An electric motor (be it AC or DC) has plenty of torque at stall. you never need to start out with the motor revving and slowly and skillfully let out the clutch, you just put it in gear (the transmission and motor are both still at this point), and press the gas… er uh accelerator pedal and away you go.)

    if any of this is wrong someone please correct me…

    but i just wanted to put in my two cents because ac motors while very nice, add a lot of expense to a project as well and i just wanted you to know your options.

  74. jerry Halstead    Mar 09, 2007 08:25 AM    #

    Hi Gene,

    You can use a DC motor with an automatic it’s just that you’ll need to have the motor idle a bit or use some other method to keep the transmission hydraulics pumped up. Efficiency will be less with automatic tranny, but that’s true with a gas motor too.

    Our first EV was manual tranny and shifting was minimal: start off in second and leave it until going above 35mph. Since our commute was local it was seldom taken out of second gear.

    All that said, if you can afford an AC system go for it: and take lots of pictures to share with us!

  75. — Scott    Mar 15, 2007 23:05 PM    #

    Jerry (or whoever),
    after plying around with the calculator, i’ve come up with a configuration that for lack of a better term is “blowing my mind”
    im showing a range of 246 miles at 70MPH using a single string of Trojan t-105 at 48V on a dodge neon with the E & S etek 48V 8HP motor. Is this even remotley realistic?
    would this motor even be able to push this type of car to these speeds? and then any guess on what acceleration would be like?
    the link to the setup ive got going is:
    Here’s a link to my EV Calculations: http://evconvert.com/tools/evcalc/?vals=veh=16:mot=4:bat=1:ctl=3:vlt=48:nst=1:dod=100:cwt=20:wtr=600:mwt=500:inc=1:wnd=0:sec=195:asp=60:rim=14:rr=0.015:bs=0.003:

  76. jerry Halstead    Mar 16, 2007 10:09 AM    #

    Sorry about that Scott, but the Etek motor was an anomaly and I’ve deleted it from the database.

    The problems with it are:

    1) data incomplete
    2) none of the controllers in the calculator go below 72volts
    3) I think it is too small for powering a car

    I’ve heard of it being used predominately in electric motorcycles.

    Specs on the motor and an EV list thread.

  77. — Scott    Mar 16, 2007 13:27 PM    #

    OK, thanks. I kinda figured the numbers were totally off the wall there.
    Was also wondering if that small of a motor was powerful enough to even move the car under all the weight of the batteries and other equipment that would be used

  78. — Gene K.    Apr 03, 2007 01:52 AM    #

    Hi All,
    I am going to throw something into the mix, I have not done a lot of research on the subject, but I have some general knowledge on the subject.
    The “Hybrid-Automatic transmission”, namely the “Clutchflite” Trans.
    I have seen two in my lifetime, but have never had the opportunity to drive one. Take a torqueflight, or perhaps any auto trans, remove the torque converter (unnecissary rotating mass), remove the pump from the front of the trans (add block-off plate to the front of the trans). add plumbing to provide hydraulic pressure to the rest of the trans (pressure comes from a power steering pump driven by a motor) in the ICE version it was running off of the engine.
    Couple your traction motor to the input shaft, and Presto!! you have an automatic EV.
    Okay, I know there will be many questions, I do not have the answers for them yet. I am just thinking out loud.
    From my limited research, they shift hard, but this could be from further modifications, I know of some of the mods we used to do for drag racing and even with a converter an auto can shift very hard (head snapping) but you aren’t letting off the gas in this situation.

    How does this effect the efficiency of the automatic?? What does it take to power a hydraulic pump?? Unknown.

    Perhaps there are some auto trans experts out there.

    Just some food for thought!!

  79. — John A. Scott    Apr 29, 2007 20:16 PM    #

    I have 31 modal A that Iam getting ready to restore and I thought what a great EV this would make. Problem, I don’t know Jack _____ about EV conversion. I am truly at the bottom of the ladder. Send help!

  80. — Ryan Davidson    May 14, 2007 04:35 AM    #

    Jerry, its been awhile but I just had a thought about batteries.

    Haven’t looked into it too much, but what about a used prius battery pack? OEM parts for a non-OEM car?

    I’ve been seeing a few used ones up on ebay for less than $1000.

    Some rewiring of the pack might suit your use better.

  81. — Ryan Davidson    May 14, 2007 04:52 AM    #

    Ok… I may have been a bit hasty.

    The 2004 era Prius battery had a 1.5KWH rating. Not that great.

    I remember now… the prius battery is a gas tank and ICE.

  82. John Harding    Jul 09, 2007 21:56 PM    #


    I’m trying to understand the figures presented on the battery page.

    If I understand Peukert correctly then the higher the Peukert Capacity the better, right?

    If so, then would the best battery for range be the one with the highest Peukert Capacity divided by weight?

    If that’s true then the Flooded Leads and GELs seem to be best (not considering Lithium – can’t afford ‘em).

    What advantages does AGM give aside from packaging (can be laid on side) and maintenance (no fluid to top up)?

    I’ve heard that AGMs can deliver higher peak amps. Is that true? If so, is there a stat that can be added to the table and introduced into the “best battery” equation?

    Also – I came across this link: smart gauge on peukert which calculates peukert capacity differently.

    Finally can someone describe the characteristics of the GEL battery? Is it more like Flooded or more like AGM?


  83. John Harding    Jul 09, 2007 22:16 PM    #

    OK I think I answered my own question courtesy of this page: How Lead Acid Batteries Work

    Note how batteries that have a high Peukerts Exponent will quickly run out of capacity with high loads. Here, the low-exponent battery will last over 100 minutes with a 50 ampere load, while the high-exponent battery will last about 20 minutes. Thus, anytime you deal with large loads relative to the battery capacity available, chose a low-exponent battery. This is why many wheel-chairs and other electrically motorized vehicles use AGMs.

    Thus the AGMs are better for high amperage loads precisely because they have low Peukert exponents. So the Peukert figures are the stat for both lifetime and higher amperage draw.

    OK – now I’m off to my spreadsheet to crunch some numbers…


  84. jerry Halstead    Jul 09, 2007 23:20 PM    #

    Uh, sure, glad we could help! ”:^)

  85. John Harding    Jul 10, 2007 19:18 PM    #

    Well you know – I can’t wait forever … ;-)

    Seriously – yours is one of the best sites I’ve found. You provide a wealth of great info and you have a very engaging writing style.

    Now that the sycophancy is out the way ;-) In case I still have your attention I had sent you an e-mail about getting access to your EV Calculator code to extend it (p.s. I know I can rip off your public javascript but I’d like to ask permission).

    Also, I’ve since noticed you are responsible for the code behind the EV Album site. Any chance I can get read-only access to the database? I’d like to slice and dice some of that data.

    Anything I did with either project would be given back to you to do with what you wish…


    you can email me at jdharding at comcast dot net assuming you want to ;-)

  86. jerry Halstead    Jul 12, 2007 12:22 PM    #

    Hi John,

    I could have sworn that I replied to your email, but with all of the baby duties and reduced sleep it’s entirely possible that I just imagined it or sent it to someone else named John.

    You can certainly snag the website scripts and build upon it and if you’d like to feed the improvements back to me I’d be all over it. I built the current calculator based on that of others.

    While I did write all of the code for the EVAlbum the data and site is owned by Mike and you’d have to check with him (links to mail him on the site).


  87. John Harding    Jul 12, 2007 14:32 PM    #

    Will do – thanks! And good luck with the bambino duties… My son is now 8 but I still remember the sleepless nights!!

  88. John Harding    Jul 12, 2007 14:42 PM    #

    Hey – check out these guys: elictric motor sports

    They sell one of the smaller Thundersky batteries for $100 for a 3.2v 40Ah battery. They claim that 4 is approx equivalent to a 60Ah PbA battery. So, $400 for a 12.8V Li-Ion battery – that’s starting to look much more affordable …

    And – in my usual “talk is cheap” (or perhaps I’m still in the brainstorming phase (yeah – that’s much better)). I’m now thinking I might start with a motorcycle (actually a maxi-scooter) conversion. Simpler and more affordable (but obviously less capable).

  89. — Gregg Aho    Jul 18, 2007 10:25 AM    #

    GENE K.I live in southeast michigan and will be building a EV also this summer out of a probe maybe we can get meet up and help each other out.or anyone else that knows how to build a EV e-mail at aho@peoplepc.com

  90. John Harding    Jul 19, 2007 18:14 PM    #

    Hi Gene & Gregg,

    I’m in Ann Arbor, MI. I’ve decided to go ahead with a scooter first. In fact I’ve just (today) ordered an X-Treme XM-2000 Elecric Moped. I don’t expect it to be all that great – but I hope to be able to modify it into something usable to commute 12 miles to work each day.

    I figured it would be much easier to work on a scooter than a car and I could still learn a bunch of useful stuff. Also, for $1600 all in it’s a great introduction to the world of EVs…

    After that I may progress to a car conversion.

    If you guys want to meet up drop me a line as well. I’m jdharding at comcast dot net.

    John H.

  91. — Gregg Aho    Jul 21, 2007 13:26 PM    #

    that sounds great. do you know any other EVers in the area?

  92. — Gene K.    Aug 03, 2007 19:45 PM    #

    Hey Gregg,
    I sent you an e-mail, Yea I would not mind checking out what you got goin on, I may even be able to give you a hand if you you need one.

  93. — Greg Coleman    May 11, 2008 23:42 PM    #

    So Jerry,
    How goes EVE? Batteries decided on yet?

  94. Jerry    May 12, 2008 07:14 AM    #

    Hi Greg,

    Yep, shooting for the Sears PM-1’s, which are supposedly the Odyssey Hawker PC2150 in re-branded packaging. A little on the expensive side but that’s what stimulus checks a for! “:^)

    I get one baby-free day a week these days, so between all of the other house chores I try to sneak in a little bit of work on Eve. Slow going, but at least it’s not freezing anymore.

  95. — James May    May 12, 2008 07:47 AM    #

    The Odyssey 2150 is the battery I am going for too.

  96. — James May    May 12, 2008 07:51 AM    #

    Odysssey PC2150