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Larry's EV II · 24 March 06

No-Gas 2

One of the more active posts on the website is Larry’s Metro EV. Over forty comments so far.

Dr. Larry has been working on the battery layout to achieve a better balance of weight between the front and the back. As part of the process he was kind enough to send an update along with a few pictures.

Be sure to click each of the images for a larger, more detailed view. At this point I’ll turn the text over to Larry:

NoGas Trunk View

Please find attached three updated pictures of “No Gas 2”.

I just finished putting four of the five batteries up front to even out the overall weight. The trunk picture shows the seven battery chargers on a charging board sitting on top of five of the drive batteries and one utility battery.

There are still three drive batteries behind the seat and now four up under the hood. I must say the car sits and drives better as now I have some weight up front where it was designed to be.

No-Gas Under hood view

I haven’t made the battery tie downs for up front yet because I just got it together. The bungee cords are there just so I can test it out on the road. The tie downs will be made of non conductive rubber angle and standard threadalls.

No-Gas Dash view

The dash picture shows a volt meter that is attached to just one of the drive batteries. The theory is that what that battery is doing the rest are as well.
(cheap way out of investing in an expensive monitoring system).

Thanks again to Larry for sending over the pics and answering everyone’s questions.

Comments 140
  1. darin    Mar 24, 2006 21:12 PM    #

    And Dr Larry’s car continues to be an inspiration to the creatively budget-minded! i love the idea of monitoring a single battery and assuming the others are similar (with an understanding that the voltmeter may be misleading).

    Correct me if i’m wrong, but the potential for “misinformation” is that (a) you may happen to be monitoring a battery which is weaker than average (leading you to think you’ve got a lower pack voltage than you actually have), or, (b) the opposite (which would be more problematic!)

    Are there any other potential drawbacks? (Aside from concerns over shorts – if I understand the info in Gordon Stalling’s battery monitor (recent Links), where monitor wires are leading from the pack into the passenger compartment, a resistor inline with the voltmeter adds some protection in case of short circuit).

    – Darin
  2. — James May    Mar 25, 2006 07:24 AM    #

    I do know that Gordon’s monitor would have saved me from my battery terminal failure because I would have been able to see the lower voltage across the battery and it’s terminals under load. It is a lot of money though so I might find some miniature panel meters. Or actually, just occured to me, a low voltage warning light circuit made with zener diodes on each battery. they’d all come on under load, but the weak one would come on sooner and stay on longer. Hmmm, I’ll think about that

  3. — Dr. Larry    Mar 25, 2006 16:53 PM    #

    Thanks for putting the second page on, it is certainly appreciated. In response to Darin, I guess there is always a danger of a short when you work with electricity. Therefor as we work on our EVs we best be sure to check it twice and try our best to make it as safe as we can. I sure do. Knowing that a battery could explode on you at any time, I always ware a clear welding face shield when I work on batteries. One can never assume that everything will go right. When ever I disconnect a battery terminal I always wrap it with tape and paper before I lay it down to prevent it from shorting out on another terminal. Also when you use a wrench tape over half of it so that it can’t become a shorting hazard. If the tool is long enough to reach across two terminals besure to tape up half of the tool. Thanks again for page II. DL

  4. — jimmy    Mar 27, 2006 01:04 AM    #

    Thanks for the pictures … I am also working on a geo metro battery placement. Are you using an aux battery for 12 V needs? Where is that ? Still trying to figure out how to puncture that brake vacuum diaphram ??

  5. — Dr. Larry    Mar 27, 2006 07:03 AM    #

    Hi Jimmy, Yep, the 12 volt utility battery is the same as the rest and not used as a drive battery. I am getting to get in it at this moment and go to work. Thanks for asking. Have a good day and good luck on your brake project. DL

  6. — Dr. Larry    Mar 27, 2006 19:44 PM    #

    Darin, I ment to tell you that one should have a battery tester that will simulate a load. They are very cheap about $17 from Harbor Freight. If you test your batteries under load once every so often you will not be guessing if your reading a bad battery with your dashboard volt meter. Any battery that doesn’t stay green under load will need to be replaced or given a less critical job like playing a radio in your garage. (smile). DL

  7. — Dr. Larry    Mar 27, 2006 19:55 PM    #

    http://www.harborfreight.com/cpi/ctaf/displayitem.taf?function=Search Hay everyone follow this web address for the tester I just mentioned to Darin. DL

  8. darin    Mar 27, 2006 21:54 PM    #

    excellent! Good advice, and thanks for the link. – Darin

  9. — Dr. Larry    Mar 29, 2006 05:20 AM    #

    Well I see that the address listed above for the battery checker is a dead end. Try this one http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90636

  10. — Dr. Larry    Apr 07, 2006 06:42 AM    #

    Two things to report 1… No Gas 2 hit a mile stone yesterday when the odometer turned over 7,000 electric miles and all without burning one drop of gas. 2… Remember I mentioned earlier that I had applied for a federal grant? Well I heard from my congressman and just as I had feared they are in no way going to help with the grant that leads me to believe there truely is a conspiracy to keep our electric car technology off the road. It was a big blow to our hops and dreams but they are not going to keep us from driving our cars and thumbing our noses at the high gas prices. Everyone keep up the good work and may our works inspire others to do what we are doing on this website. DL

  11. — Dr. Larry    Apr 28, 2006 21:23 PM    #

    My friend Bob has recently purchased a 1960 VW Bug and his plans are to convert it. The interior and exterior are in really good shape as this car has been garaged for most of it’s life. I am hoping to keep you informed of his progress with the car and even some pictures. He has now removed the gas tank and is getting ready to remove the engine, by the way it runs very well, but hay who needs a gas engine anyway right?

  12. — Mike    May 27, 2006 00:42 AM    #

    Dr. Larry, I love reading about real world conversions with real world results. You and Jerry are great examples. I would love to read more detailed information about you’re conversion as you seem to have broken some rules here with Wallmart batteries and chargers and are getting practical use out of them. I am currently woking on finishing my fathers EV project, a 1970 fiat 850. He passed away before completing it. It has a 8” 96 volt Advanced Dc motor and curtis controller. I scoure the net looking for info and when I stumble across a site like Jerry’s I can’t stop reading untill I’m finished.

  13. — Dr. Larry    May 28, 2006 22:26 PM    #

    Hi Mike-
    Thanks for you comments. It is just wonderful that you are carrying on the work your father started. You are completing a dream he had. Your right this is a wonderful site. You may also take a look at another site that Jerry and I are on www.austinev.com
    Thanks agian.
    Dr. Larry

  14. darin    May 28, 2006 23:32 PM    #

    Hi Dr Larry –

    How are your batteries holding up? You’ve put a few miles on them now! Has your range changed at all? Cheers – Darin

  15. — Dr. Larry    May 29, 2006 17:59 PM    #

    Hi Darin
    Since the car’s creation about 3 years ago I have yet to experience a bad battery. I took the first set of batteries and put them in the basement for the solar electric system here at the house. I replaced them with a slightly larger battery and these have been on the road for several thousand miles. In the house and in the car these batteries seem to be like timex watches. Strange thing, the larger the battery the cheaper they seem to be. I do not notice any difference in range another indicator that the batteries are holding up. About 50 miles each charge but I don’t run them all the way down. I may only drive 20 miles or less each day. Thanks for asking. Dr. Larry

  16. — Ernman    Jun 12, 2006 16:18 PM    #

    Dr. Larry,
    Great work on the car. I am intrested in using the AXE controller, and a 400 Amp surplus motor that others have used with this controller. I can’t seem to tell if you are using any contactors with your setup. If you are what type are you using? What size wire did you wind up using? Do you have any other tips on wiring?

  17. — Dr. Larry Tillman    Jun 12, 2006 20:46 PM    #

    Hi Ernman
    I ended up using a #2 welding cable and I suggest getting the solder on lugs and solder them on yourself. This way you know what kind of a connection your getting. I used a 60/40 electric solder and it seems to work well. If you keep the battery terminals tight you should have no heating. There are no contactors as everything is electronic switching. One other thing.. I know I have some wires that could be shortened in the picture, but I would suggest cutting the cables no longer then they need be to keep the resistance down. The last battery in the drive string is right next to the voltage controler for the shortest run. Thanks for your comments and have lots of fun with your EV….Dr. Larry

  18. — Robert Proctor    Aug 01, 2006 17:21 PM    #

    I have a 2000 Geo Metro I want to convert. I am interested in how you were able to do what you did with so few dollars. As well… What range do you have? Why DC and not AC? Can you provide more tech. info.? Maybe Larry’s Metro kit for $3995.00

  19. — Anonymous    Aug 04, 2006 02:42 AM    #

    I am also interested in the specifics of your conversion for my 1998 Suzuki Swift (aka Geo Metro). :)

    Most conversion kits out there for these cars seem to run around $10,000. It sounds like your car is fully functional, capable of freeway speeds, and yet made much more cheaply. Although I might be willing to spring for a better battery monitoring system.

  20. — Dr. Larry    Aug 06, 2006 21:39 PM    #

    There are those who want to make money and there is nothing wrong with that however if you do the work yourself there is no reason why it has to be expensive. I took a very practicle approach to the conversion. For instance, you ask where do I get a charger? Well heck auto or department stores sell them all the time. Why buy a special charger when all you want to do is charge a 12 volt battery. Buy several to get the job done like I did and when one goes bad just replace it. It’s not a speciality charger and it available almost everywhere. Batteries…...Do the same thing. I find the flooded batteries work just fine. Who said they have to be expensive to do the job? I got all of mine at Wal Mart for about $60 each plus core charge and I have just the other day had to replace one because it developed an internal short. The warrently was still on the battery so I was out very little. I spent more money going after it then it actually cost to replace it. I guess the secret is look at what you want to achieve look for the things you need locally. Everything does not have to be a speciality item. I only have three speciality items on the car. The throttle sensor, motor and voltage controler. I now have put 8,770 miles on this car and the conversion only cost $4,000. Heck you can’t buy a good used car for that. Anyone wanting to see this for themselves leave a message here and I will be glad to leave you informatin on how we can get together for you to check out this car and yes even drive it.
    Dr. Larry

  21. — Mark J.    Aug 08, 2006 02:48 AM    #

    Dr. Larry, could you explain how you are using multiple battery chargers. Does that mean you are disconnecting all your batteries and hooking up chargers ? Thank you very much for your time, Mark.

  22. — James May    Aug 09, 2006 17:29 PM    #

    If the battery chargers have the low voltage side “floating” with repect to the high voltage side (this is true for most types of transformer) then the chargers can be stacked in series and all run from the same power supply, I guess this is what Larry is doing. Means you dont have to disconnect the batteries to charge them.

  23. — Mark J.    Aug 10, 2006 01:53 AM    #

    Thanks you James!

  24. — Dr. Larry    Aug 10, 2006 06:53 AM    #

    Hello again guys;
    First understand that I have a 72 volt system. To get that voltage I have 6 12 volt deep cycle batteries hooked in series to provide the voltage. To each of those batteries that are in series I have an identicle battery hooked in parallel. Each battery that is in series has a single charger. It remains hooked to the battery at all times. It will not only charge the battery it is hooked to but also the battery that is parallel to it. I hope this clears up the mystery.

  25. — Mark J.    Aug 10, 2006 15:29 PM    #

    Thank you Dr. Larry! I didn’t know that was possible.

  26. — Anastasia    Aug 12, 2006 07:53 AM    #

    I’m curious if you could let us know how much electricity your car consumes. How many watt hours do you average per mile?

  27. — Dr. Larry    Aug 15, 2006 05:47 AM    #

    I never done the math to figure watt hours. However I had a friend bring his wrap around amp meter and we were able to pull 230 amps at one point pulling both of us up a hill. I know what the range is and how the hills around locally affect the car I just go with that. Thanks for asking.

  28. — Dr. Larry    Sep 04, 2006 18:45 PM    #

    Today (Labor Day) the wife and I drove 23 miles in the EV to be in the parade at Cedarville, Ohio. Home of the father of Labor Day. The trip seemed short enough and we had plenty of charge or so I thought, it seems that on the way home we started loosing some serious power and I was thinking what the heck? After creeping home a closer examination reveiled that not one not two but three battery connections had come loose and was heating the wires. I just tightened all of these connections not 100 miles ago. This is a problem that I seem to have with this setup. So I expect it will be a problem for you as well if one does not check frequently your connectors. One thing you can do is check for hot cables after a run to see if there is any heating going on. Heating is wasted energy and that is what happened to me today. So check those connections often. Once they get loose from the heating and cooling of pulling amps they will loosen up and trouble begins. I keep two battery wrenches right in the car now. Have fun

  29. — James May    Sep 05, 2006 06:45 AM    #

    Hi Dr Larry

    I am familiar with this problem. One of my terminals melted a while back and now I tighten them all every 2 weeks or so. They also have spring washers. I have just built, but not yet fitted, a homemade battery monitor. I will go public with it soon on this site. The idea with this is that if any battery / connection is showing unusual voltage under load, I’ll be able to see it on my status lights. It’ll show up a bad connection. I’m glad you and your wife managed to get home OK. I also always carry an insulated spanner (wrench) for emergencies. And a jump lead to span a battery if one dies individually.(disconnect it first of course).

  30. — James May    Sep 05, 2006 06:49 AM    #

    I have other woes at the moment, My car failed the MOT safety test so It’s currently in for brake repairs. My main problem right now is that my Zivan K2 96V charger has let go in a big way. It has blown a diode and 2 MOSFET power transistors. I have had to order them. They’ve been shipped from America. Not very common parts. I hope I can fix it. I have been charging individually with a standard battery charger in rotation 2 at a time.

  31. — Dr. Larry    Sep 07, 2006 09:34 AM    #

    Hi James
    This is the very reason I decided to go with off the shelf battery chargers and not a speciality charger. If one goes down (and they sometimes do) just go and pick up another one at any department store or auto supply. Mount them all on a board and that sits right on top of the batteries I have in the trunk. You might consider this move to simplify things.

  32. — James May    Sep 07, 2006 16:06 PM    #

    Hi Larry,
    Yes I might consider this! I have repaired the charger. It needed yet another two diodes. It has lasted 2 hours and blown up again. This time it is a capacitor. I’ll try once more.

  33. — noel    Sep 07, 2006 16:50 PM    #

    Are all the chargers wired together so you only use one wall plug? Does the gas from the batteries corrode the chargers perched on top of them?
    I like your ideas…they remind me of some of the articles I read in “Car Craft” magazine.

  34. — Dr. Larry    Sep 07, 2006 17:44 PM    #

    Yea I have a multi-power strip the kind you buy in any hardware store that has all of the chargers pluged into. As for hydrogen gas, take a look at the chargers see that computer fan sitting next to them. That blows over the chargers to take care of any gas that may form. Each charger has a built in cooling fan and they are not made of any metal so they won’t corrode.

  35. — Dr. Larry    Sep 19, 2006 09:34 AM    #

    Hi Guys
    I may be changing ISPs but for the moment I can still respond here through my daughter’s RR. She lives next door a few feet away so no problem.
    Happy ampering

  36. — Greg    Sep 21, 2006 17:26 PM    #


    Impressive work. I’m a newbie and clearly have a bit of reading to do still. This being the third year we have seen $3+/gal, I about had enough. A full time student it will likely be another year before I can start on an EV car… in the meantime I bought an 500w electric moped, a Q-Electric Expresso S, maroon, cheap crappy construction, but it runs like a top, and it’s enough to hook me on electric power. Broad torque curve, smooth, silent, clean, and I can bring the thing inside and charge at work. Never have put the pedals on, though since I have them with me (they are functional, it’s just safer not having them out to snag anything). Incidentally, I highly recommmend simliar vehicles but not Q-Electric’s. There are better ones produced with a little more power though that requires registration, insurance, motorcycle endoresment in Oregon and probably most if not all other states.

    Since I won’t be affording a Tesla Roadster anytime soon and I’d been considering a used Metro anyways simply because of the economy, I’ll probably go with something similar to your setup. The red convertable does give yours an edge of sportiness!

    I was under the impression that EV’s using Lead Acid batteries really needed to use SLA’s as car batteries aren’t designed to be discharged and charged repeatedly like that. Also, the SLA’s are supposedly safer as they don’t have liquid battery acid.

    I was thinking that a Metro could make a GREAT around town vehicle and be surpsingly fast if a larger motor is installed, my theory being that a larger motor (but within reason for the rest of the stock driveline, perhaps a 10kw motor (continuous) with a peak rating of 80kw or so for some good ‘ol punch in the nose. Obviously this has the potential to greatly cut into range or put a lot of stress on the motor and drive system if abused. Most of the time there would be just one or two adults, and I’m 145lbs. Oregon is not excatly flat, so the extra power would be needed for hill climbing. As I recall Metros don’t have power steering either, some of the older models don’t have power brakes, but I could be mistaken.

    Would love to hear yours and others’ thoughts on the above! Congrats again, wish I lived near Austin!

  37. — Dr. Larry Tillman    Oct 03, 2006 18:34 PM    #

    Hi Greg, I don’t live in austin, I live in south Charleston, Ohio. Your right, regular car batteres will never take the punishment of repeated charging and discharging. The plates are too thin about the thickness of screen wire. The deep cycle batteries have very thick plates that can take the punishment. Most deep cycle batteries are good for about 400 to 500 cycles. That is a lot of driving. The Metro makes a great drive around town car. Long trips are a problem for any EV. Most people drive less then 50 miles a day and that makes it just right for most folks. Thanks for the comments.

  38. — Charles    Jan 09, 2007 11:58 AM    #

    I wanted to say that i really appreciate your budget approach and was wondering if you could give a line-by-line list of your parts and cost.

    I dont have the time or money to do a conversion right now, but i am very interested sometime in the future, and my parents do have a 93 plymouth acclaim that makes me salivate at the possibilities….

  39. — Jim    Jan 28, 2007 01:00 AM    #

    Hi Dr. Larry:

    I am a very enthusiastic EV fan, especially after reading your comments and viewing the details of your EV. Just fantastic!

    I am definitely an EV novice, but am trying to learn in order to put one together myself.

    One of your responses to another EV fan’s question was: “First understand that I have a 72 volt system. To get that voltage I have 6 12 volt deep cycle batteries hooked in series to provide the voltage. To each of those batteries that are in series I have an identicle battery hooked in parallel”.

    What are the second set of six batteries for?

    By the way, I live in Columbus, Ohio. If you plan on having your EV on public display next spring or summer, I would love to see it.

  40. — Charles    Jan 28, 2007 11:02 AM    #

    The second set of batteries halves the amount of current each battery needs to output so it doubles his range (and actually this will mean less wasted heat in the batteries and therefore will more than double)

    *All this is if i understand the situation correctly.. so correct me if im wrong.

  41. jerry Halstead    Jan 28, 2007 11:43 AM    #

    Another way of thinking about it is that the lower your system voltage is, the higher the current draw. Watts = voltage * current, so an EV with half the voltage will draw twice the current to get the same amount of power.

    When all else is equal (notably the internal battery resistance) and two batteries are placed in parallel they “share” the current duties, each supplying half. You aren’t stressing individual batteries with excessive current draw and they discharge slower.

    In practice the current draw won’t be exactly half, owing to differing chemistry and internal resistance, but it should be close enough. The thing to keep an eye out for is if one battery starts using more water than its “twin.” This would be an indication that it is taking on much more of the current load and being discharged more rapidly than the other, leading to earlier failure.

  42. — Charles    Jan 28, 2007 13:13 PM    #

    Excellent points, and i presume that if it werent for his unique charging situation this would probably not be a good idea.

  43. — Jim    Jan 28, 2007 22:01 PM    #

    Thanks, Jerry and Charles:

    Now I understand why Dr. Larry put in 2 sets of batteries. Makes a lot of sense. Wonder why other EV enthusiests haven’t done it, or maybe they have.

  44. jerry Halstead    Jan 29, 2007 08:00 AM    #

    Some do this by using bigger batteries, like 6 volt deep cycle batteries. Many of the “early” EVs were low voltage (using aircraft starters) with a long string of 6v batts. Six volt deep cycle batteries are built tougher than their 12v counterparts and able to handle heavier currents, store more energy, and have at least three times (or more) the life expectancy.

    The downside for paralleling batteries is that when one of them starts to fail it will probably take its “twin” with it.

    If one of the battery’s cells starts failing it won’t be able to reach a full charge. In a normal series chain this means the overall battery voltage goes down a bit and other cells end up working a little harder.

    But when there’s another battery in parallel, the bad “twin” constantly discharges it in trying maintain an equilibrium. Now you have a good battery which never gets fully charged and will eventually start to fail.

  45. — Justin    Jan 29, 2007 19:41 PM    #

    A good battery management system will prevent one bad battery from adversely effecting others, as well as improving the life of the whole pack by preventing overcharging of individual batteries, while at the same time allowing charging to continue normally where required.

    Different battery chemistries have different tolerances to abuse, and require different management systems. Lead acid are very resistant to most of the horrible things we do to them, and relatively simple chargers will do the job. Some of the home brew chargers out there are positively frightening. LiIon on the other hand requires that battery voltages and currents remain within very tight margins, and a lot of the advanced chargers have variable charging profiles to keep memory effects etc to a minimum.

    In an ideal world, each cell would have its own management circuit (as in the battery pack used in the Tesla vehicle). This system will permanently bypass a bad cell without noticeable impact on performance. This design obviously poses problems when 6 cells are incorporated into one battery (in the case of a 12V lead acid for example). When a battery goes ‘bad’, it’s usually caused by the individual cells getting out of balance relative to each other, be it a result of abuse or a design flaw. Even if you regulate the charging voltage to the battery perfectly, if one cell charges before the others, the remaining cells can be overcharged, causing heating and all its side effects.

    Ballpark figures, a battery management system will run you around $100 per battery, but is well worth it IMHO, especially if you are running any battery configuration other than straight series.

  46. — Dr. Larry    Feb 27, 2007 10:22 AM    #

    There is one thing I would like to add. I will sometimes try to switch the batteries so the front battery doesn’t take all of the punishment. I have no set schedule for this and just play it by ear. As for watering the batteries. I use all sealed batteries and so far have not had to add any water. The EV now has well over 10,000 miles on it. And without burning one drop of gas!!!!

  47. — Dave    Mar 11, 2007 00:57 AM    #


    Can I trouble you with three questions? (1) Why did you adopt a 72 volt system, rather than stringing all your batteries in series. (2) Do you know how much the car weighed with the ICE pulled out? (I’m surprised the after-conversion weight is so low.) (3) Which model D&D motor did you use? Thanks in advance!

  48. — Charles    Mar 11, 2007 10:56 AM    #

    Im guessing that the reason for #1 is simply money. 72V components (motor, controller, etc) are cheaper than 144V components. Dr Larry has a unigue charging system as well. Rather than 2 strings he has one string of 6 2-battery “gangs” allowing him to charge with off-the-shelf (cheap) 12V chargers. If he “stringed” (strung??) them all together he would need 12 chargers.

  49. — Dr. Larry    Mar 17, 2007 20:18 PM    #

    I couldn’t have said it better Charles. (additional) There are others still leaving messages on the first page of this article.

  50. Gavin Shoebridge    Mar 18, 2007 05:56 AM    #

    Dr Larry,
    I’m very curious about your series-wired battery charger setup.
    It just seems too easy!

    The ‘proper’ chargers available from EV stores are $2000+ for my proposed 144 volt system.

    Does this mean I can run out and buy 12 cheap & cheerful chargers instead and wire them all together?

    It sounds too good to be true. What special requirements are there to do this?

  51. — Dr. Larry    Mar 27, 2007 12:56 PM    #

    No you don’t wire them all together. However many batteries you have just put one charger on each of them and plug them all into a seperage strip and plug the strip into the outlet and you have a cheap charger. I have a 72 volt system with 6 12 volt batteries wired in series. To each one of those I have another hooked parallel. To each two batteries (parallel) I have one charger. So there are seven chargers on my car one is for the utility battery for all of the 12 volt applications that the car normally had anyway. Hope this helps.

  52. Gavin Shoebridge    Mar 27, 2007 15:39 PM    #

    Ah, gotcha!
    Sounds like a bit too much work for a lazy person like me.
    I’m interested in constructing a “bad boy” charger but there are two small drawbacks.
    1: I don’t know how.
    2: See “1”.

  53. Mark Jeffers    Mar 27, 2007 20:11 PM    #

    Gavin, Dr Larry’s set up would be very hard to beat. His batteries and chargers are available at any Walmart. And I do believe Walmart has changed battery suppliers and now sells wet cells. Talk to the auto dept, they can get stuff they don’t have on desplay. Sams Club sells golf cart batts cheap.

  54. — Dr. Larry    Apr 01, 2007 21:44 PM    #

    Garvin- Mark is right, it is really very simple and yes everything comes from WalMart. So if your on a budget and who isn’t, try some very common off-the-shelf items like I did. I still get 50 miles to a charge when the weather is above 45 degrees.

  55. Gavin Shoebridge    Apr 02, 2007 04:53 AM    #

    We don’t have Walmart in New Zealand (I assume it’s a big “sells-everything” megamart?).
    I’m trying to picture your battery charging system from your description but it seems like you’d have to rearrange half your battery connections from series to paralell each time you charge?
    If you have a spare 5 minutes could you (or someone who knows this setup) throw a simple schematic diagram together?

    Also, do you use deep cycle batteries in your EV or normal car-starter batteries?
    What specs are your batteries?


  56. Gavin Shoebridge    Apr 02, 2007 05:08 AM    #

    Larry, I’ve got it. It was so simple I couldn’t comprehend it!

    You simply have a charger for each battery. Full stop.

    The extra batteries you have are wired in parallel only to give more range, right?

    The thing that would worry me is having all those chargers sitting there disconnected while driving, and 400 amps is trying to travel through them instead of the main cable.
    Is this a problem or is it just a case of ‘path of least resistance’?


  57. — James May    Apr 02, 2007 07:07 AM    #

    I expect they have a blocking diode to prevent them from draining the batteries when they are off. They must, in fact, bacause they must be using a rectifier bridge to get the 14 or so volts DC from the AC after the step down transformer. With the diodes / rectifier bridge there power won’t be going back into the chargers at any appreciable rate.

  58. — Dr. Larry    Apr 02, 2007 08:13 AM    #

    James, your absolutly correct. The chargers could not be damaged due to protective diodes built into the chargers. So you do not have to ever unhook them even while driving or charging from even another source. This is a very simple system and it has been working fine for well over 10,000 miles of EV driving.

  59. Gavin Shoebridge    Apr 02, 2007 15:53 PM    #

    Brilliant Larry!
    I like it a lot!

    To reduce weight, I was even thinking of putting 12 chargers in a wall mounted box next to the car, all connected to the car via a 24 cord cable (one for each charger’s output).
    If I use quality cable there should be very little voltage drop affecting the charging process too in theory.

    I’d need to find a 24-pin connector that could handle the gentle 12v charging current but I could even fit it where the gas cap used to go.

    Any thoughts? Anything I’ve missed?

  60. jerry Halstead    Apr 02, 2007 16:18 PM    #

    One thing to consider with this approach is the cumulative current of all the chargers. Dr. Larry only runs a 72v pack, so there are only six chargers (or seven) hooked to the AC line. I bet if you had 12 of them all trying to sip from the same AC line you’d run the risk of popping the circuit breaker. You could get around this at home by plugging some into a separate circuit.

    Also you should size any power strips, extension cords and cables accordingly. It’s not what you can get away with (i.e. just covering the current draw) but also the losses you’ll incur going through each one. Remember, everything is a resistor and the smaller and/or longer the wire, even in an extension cord or an AC plug, the more resistance and less power you’ll get out the other end.

    We had an old, loose AC jack in the garage and I noticed once when unplugging the charger before it was done charging that the plug was warm. The resistance of the loose/dirty connection was being heated up by the high current draw. Less power to the EV, literally being wasted as heat.

    Every connection and circuit between the wall and your batteries is a place to lose power. Generally people don’t even consider this, but when you are pulling down the amount of power needed to charge an EV these losses add up.

    Most of all, be safe. Remember, just because everything is running along fine at the beginning you still need to check it from time to time. You are putting them into a dirty environment with moisture and probably some amount of battery fumes, all of which can lead to corrision, more resistance, and wasted power or other problems.

  61. Gavin Shoebridge    Apr 02, 2007 23:04 PM    #

    Good points Jerry.
    I’m normally Captain Safety, especially when it comes to electricity, so I might have another circuit installed.
    We’re on 240 volts down here too which is just as terrifying to play with.

  62. Gavin Shoebridge    Apr 03, 2007 05:41 AM    #

    I’ve been thinking about this charging setup all day (beats working), but I’ve been stumped trying to find a compact 24-pin male & female connector to replace the petrol cap space. Most importantly it must be able to handle a good 5 amps of 12v current through each pin.

    I found this:

    But I think it’s just a little too small for the 12 volt current (but only just).
    Anyone think of another (heavier duty) 24-pin plug set I could use?
    Even two 12 pin plugs I could join together would work.
    I’m open to suggestions.

  63. — James May    Apr 03, 2007 08:10 AM    #

    Hi Gavin,

    That computer connetor looks too weedy to me

    here’s an 8 pole 6A connector

    24 pole

    another 24 pole
    None of these look very heavy duty.

  64. — John Jackson    Apr 03, 2007 20:13 PM    #

    Try the following link page 743. http://www.McMaster.com/

    Says they will handle 16A/pole

  65. Gavin Shoebridge    Apr 03, 2007 23:30 PM    #

    Brilliant! Thanks JJ!
    That looks perfect. I’ll just have to figure out what that 5×3 inch plug equals in metric and measure the gas filler area but that sounds perfect.

    I couldn’t see if they shipped overseas or not (page loaded with errors) but if not I have a mate in Arizona I’ll forward it to.

    Thanks again!

  66. — Dan P.    Apr 04, 2007 02:03 AM    #

    5 inch = 12.7 centimeter
    3 inch = 7.62 centimeter

  67. — John Jackson    Apr 04, 2007 20:57 PM    #

    Hi Gavin,
    McMaster-Carr ships worldwide. Here is a copy of how to place orders. I deal with a number of vendors and at least locally(California) these guys are by far the best. I have ordered as late as 4:30 pm and received orders before I returned to work the next morning at 7:00 am.

    Ordering Information

    You’ve used the Internet Catalog to browse the products we offer. What’s next?

    I am ready to place an order. How do I do this?

    Use whatever method is most convenient for you. We accept orders via phone, fax, e-mail, EDI, and this web site. You do not need to use McMaster-Carr part numbers to order. After you place your order, we can send you an acknowledgement via fax or e-mail.

    How do I place my first order on the internet?

    You do not need to sign in or register to place orders on the internet. Just tell us your shipping and billing addresses the first time you order and we will save the information for future orders.

    What are your business and Will Call hours?

    We take orders 24 hours a day, 7 days a week. Will Call pickup is available during the following hours.

    I could not find exactly what I needed in the catalog. Can you help me?

    We can help you find the product you need. Fax or e-mail us a description, manufacturer part number, or drawing, or give us a call.

    How soon will my order arrive?

    Most orders are delivered the same or next business day at standard ground rates. More than 98% of the products ordered are shipped from our inventory. We use many different carriers in order to provide you with fast deliveries, but if you need a special delivery or would like to pick up your order at our Will Call counters, just let us know. Some of the most frequently requested carriers are available for you to select when ordering online; if your favorite is not shown, just click on “Other” in the “Shipping Methods” box.

    Do you ship orders outside the United States?

    We ship our products throughout the world using air and ocean transportation services.

    Do you accept small orders?

    Absolutely! At McMaster-Carr, we do not have order minimums.

    Can I purchase material from you without being charged tax?

    We charge sales tax in California, Illinois, Ohio, New Jersey, and Georgia. If you are located in one of these states, fax or mail us a signed copy of your resale card or certificate. If your tax status varies, you can let us know when you place your order.

    How do I return or exchange something?

    Simply send the items to McMaster-Carr and you will be given credit upon our receipt of the material. There’s no need to contact us, and we do not require a Return Authorization Number. If you would like to exchange the material, just return the items you don’t want and place a new order.

    What if I need product information that is not shown in the catalog?

    Call, fax, or e-mail us to let us know what kind of information you need. We have Material Safety Data Sheets (MSDSs) available on request for all products classified as hazardous by OSHA. Additionally, MSDSs, along with 3-D models and technical drawings are available for some products on our web site.

    What if I need additional information about an order I already placed?

    You can send us an e-mail if you need a copy of your invoice, a proof of delivery, or other shipment information.

    What is McMaster-Carr’s federal tax ID and DUNS number?

    Our federal tax ID number is 36-1458720. Our DUNS number is 029404068. Our cage code is 3A054.

    I am ready to pay my invoice. How do I do this?

    You can mail your check to us at PO Box 7690, Chicago, IL 60680 or call us to pay by credit card.

  68. Gavin Shoebridge    Apr 05, 2007 07:58 AM    #

    Excellent, it get’s better and better!
    Nick Smith has shown me something quite similar ex Australia which I’m keeping my eyes on.

    At the moment I’m waiting to hear back from the bank about lending me the money for the electric motor.
    I picked up my new gearbox today too. This one doesn’t have a hole in it! Hurrah!

  69. — Dr. Larry    Apr 14, 2007 20:27 PM    #

    I am so pleased to see so much discussion here. Come Monday I am taking the Geo EV over to have a new top put on. I ordered one from J C Whitney and they were very reasonable on the price. The old one was looking pretty bad and I was kind of ashamed of it when I had to go out but now the car should be looking good. Enjoy

  70. G. MICHAEL YOST    Apr 27, 2007 21:45 PM    #

    For Larry!!!!
    Do you have a parts list for your conversion and if so is it available to me?

  71. — Dr. Larry    Apr 29, 2007 21:32 PM    #

    For G. Michael Yost
    The parts are all buried in the invoices I have collected and never really made an official list of parts however there are many good web sites you can go to for basic parts infomation. I would put your request into google search and see what happens. The parts are few. Batteries, wire, motor, voltage controler, charger/s and throttle sensor.

  72. — Mike Smyth    May 09, 2007 22:50 PM    #

    Hello Larry,
    I made it from the other page finally. Thanks, for the reply. Just purchased the controller for the conversion today on EBay. (An Alltrax 7245, Gets me all excited to finally see some parts coming together. Wife thinks I’m crazy.) I’ve finally come to the conculsion that I am going to have some some problems with range and that is just the way it is going to be. The area of Ohio that I am in is right along the Ohio river and very hilly. There may be some trips that I just can’t take with it if I’m going in a direction that is excessively hilly. As for the batteries, I’m going the same route as you. I’ve got it narrowed down to the Everstart 27DC-6 or the Everstart Maxx Marine 29. I am leaning more toward the 27DC-6 because it is a true deep-cycle whereas the Maxx is a hybrid of a deep-cycle and a starting battery. I’ve been reading several different posts that state it shouldn’t be discharged below 50% DOD often as it will shorten its life drastically. The literature that I read at WM doesn’t say anything about that though and if you ask the salesperson what they think they just kind of look at you funny and say “Its for what?” (Another little bit of info. The 27DC-6 I have found through my reading is made by Exide and the Maxx is made by Johnson Controls and Exide depending where you are in the country. Here in Ohio I believe it is Johnson Controls who also makes the Optima.) As for the chargers, you have sold me. I’m stepping it up a notch to the SC-1200a’s though. I’m working 12 hour shifts this summer and want to make sure its charged at work before I have to drive home 23 miles uphill. I know that this is going to take all summer to complete. Just hope I can get it done before gas hits $4.00 a gallon. I’m looking for input from people about the 2 battery choices and the choice of chargers.


  73. Gavin Shoebridge    May 10, 2007 22:16 PM    #

    And now it’s time for Gavin’s Stupid Question #74:
    This is a theoretical question but if I have 12 chargers all sipping 3amps at 12V DC, is that equal to 3amps 220 Volts AC going INTO each charger?
    I mean, if my charger is drawing 3 amps into the battery at 12 volts, is it also drawing 3amps from the wall socket?

  74. — Brad Ohsann    May 10, 2007 23:56 PM    #

    If you are charging a 12volt battery at 3amps then you would only use .3amps of 120v from the wall. 120/12=a factor of 10. This is if the charger were 100% effecient which none are so it will be slightly more, maybe .4amps. With 12 batteries and chargers @ 3amps the math comes out to about 2amps. 144/220=.655 3A*.655=1.965amps. Don’t forget to add for inefficencey. Hope this helps.

  75. — Mike Smyth    May 11, 2007 00:01 AM    #

    Hello Gavin,
    3 amps at 12v is equal to 0.3A at 120v. Doesn’t matter whether its AC or DC. Current, (or Amps) is inversely proportionate to Voltage. If you have 12 chargers pushing 3 amps for a total of 36A at 12 volts, in a perfect world you would be pulling 3.6 amps at the wall. However the world is not perfect and we have voltage fluctuations and loses due to heat and conversion from AC to DC. I think its safe to say your pulling 4-6 Amps at the wall depending on the quality of your chargers. Hope that helps.


  76. — Brad Ohsann    May 11, 2007 00:15 AM    #

    Hi Mike,
    I could be wrong about this, you are correct at 120volts, 36amps would be 3.6amps. I thing Gavin uses 220volt AC which would cut the current in half. Yes nothing is perfect. If his chargers were 80% efficent that should put his current at 2.5amps.

  77. — Mike Smyth    May 11, 2007 00:15 AM    #

    About the above post, I see someone answered the same time I did. It would be 4-6 Amps at 120v or 2-3 Amps at 220V. Once Again dependant upon quality of chargers. (Alingment of stars, Second Tuesday of 13th month, ect..)


  78. — Mike Smyth    May 11, 2007 00:21 AM    #

    Hi Brad,
    You were dead on. I missed the 220v on my first response. I see we answered at the exact same time again.

  79. Gavin Shoebridge    May 11, 2007 06:15 AM    #

    Awesome stuff, you’ve both been very helpful!
    Thanks for that! :)

  80. — mke    May 11, 2007 13:56 PM    #

    Hi I want to convert my Chevy Cavalier(2004) in a EV could you point me in the right direction I’m not doing it alone there is a group of people over in eastcost who want to try and do our part in bring back the Ev car’s we are all going out to find as much info as we can on how to do it and we are using our own cars new or old I hope you can help you can Email me at
    mikesmts@hotmail.com I dont know how much its going to cost but im will to save up and do a little at a time tell its done.

  81. ohio    May 12, 2007 10:49 AM    #

    hi mike i am all most done with mine
    if u need batts i can sell you agm batts at low cost if you pick them up at my shop.


  82. — Mike Smyth    May 14, 2007 10:36 AM    #

    Hello Ohio,
    I checked out your website for your Saturn. looking good but you need more pics. I see the type of batteries that you are using and I would love to have them but it I think they will blow my budget. I’m looking for something that can be serviced locally if I need warranty work or replacement. I’ve added a third battery to the possibilities. I went to Sams club and I see that they have Energizer Deep cells with 125ah storage. Might be a possibility. Price is right too at $52.00.

  83. — Dr. Larry    May 17, 2007 21:07 PM    #

    Hi Mike
    Be sure that when you get ready to hook up the battery wires you use the solder in lug terminals and not the clamp kind. I can’t begin to tell you just how much those things gave me problems. They like to loosen up when they heat and cool but not with the solder in type.


    I also have a question for everyone reading this, I got a letter from my insurance company telling me that they could no longer continue to insure the car for the value I had placed on it ($12,000) instead they would only replace the book value of the car before it was modified and for an old Geo Metro (1991) like this one that is almost nothing. So now I got to find a company who will insure a car that has been modified. as anyone run into this problem. I just have collision on the car now and frankly it frightens me. something else to think about, if someone else runs into your car their insurance company may fight paying you anything at all because of the changes you made to it or they will only pay book value of the car before modification.
  84. — Dan P.    May 18, 2007 01:45 AM    #


    You might want to ask the stretched Limousine companies who they use for insurance and you could look into some of the antique car clubs since they too have spent more in restoring and or modifying their street rods then any book could possibly value them at.

    Here is a link to some registered car clubs by state so you guys can try to contact one near you.

    PS My widowed mother is the proud owner of her deceased husbands 1963 Nova convertible; I’m the same age as the car but I think it looks better then me. She is also a member of Dixieland Cruisers and performs at car shows for Breast Cancer Charity as one of the “Pink Ladies” (Shameless Plug for good old mom!).
    http://dixielandcruisers.freeservers.com/slide_show.html?show=Slide_Show_Bill_Warner&picture=picture1.jpg There is even a picture of me here eating some home made southern ice cream, I think the flavor was Jack Daniels but I could be wrong.

  85. — infinitely    May 24, 2007 15:43 PM    #

    I am working on the prototype for a solar powered climate control system, for a green house. It has solar panels that charge the batteries, the batteries run the fans that are on a thermostat and the humidifiers that have a hygrometer built in. I was thinking that lithium ion batteries would be the best choice. What do you think is the best battery option, considering that the draw from the batteries is almost constant and the charging is happening almost constantly also. I also thought you might know, what is the most efficient type of solar panel today, with cost considered?


  86. — James May    May 24, 2007 17:25 PM    #

    Hi Infinitely

    I would use flooded lead acid batteries. They’re cheap and robust and don’t lose much energy over the charge/discharge cycle. The disadvantages of lead acid, weight and low charge density, do not apply in a static situation.

    You can buy kits for outhouse solar powered lights that contain solar panels. Might be a good place to start if you are not feeling confident. I have just bought a kit like this for experimentation.

  87. — James May    May 24, 2007 17:33 PM    #

    You need to match the battery size to the panels and the load.
    For example, my little solar lighting kit has a nominal approx 16V 6W panel and says that if the lights aren’t used much in the summer you’ll need at least a 12V 75 Ah battery to prevent it from getting overcharged. There is no charge regulator in this little kit.

  88. — John    Jun 13, 2007 23:17 PM    #

    HI Larry !

    Incredible project ! Just bought a 1995 firefly and took all your advices to convert it. Only one simple question: How did you build your transmission adapter ? Not sure what i need to look at right now …

    Great job !

  89. — Dr. Larry    Jun 16, 2007 16:28 PM    #

    Hi John
    When you get the motor out you will have a transmission shaft sticking out from the transmission. Take a piece of cardboard and trace arount the opening of the transmission. Use this template to mark and cut a piece of steel plate that you will cut and drill mounting bold holes. Cut a circle in the center where the transmission shaft comes out and you will have a place now to drill and bolt your motor to. Hope this helps. If you need I can work on sending a picture of what I am talking about. Thanks for your comments

  90. — John    Jun 16, 2007 17:39 PM    #

    I’m right now at the point where i got rid of the extras (engine, tank, exhaust, etc)and planning the parts to buy. I’m planning to get something like a D&D 10hp and an Altrax 7245 (going the 72 volts way like you) 3 tranny questions: 1) how thick is your metal plate ? 2) how do you connect the motor to the tranny (coupling) ? 3) did you retain the clutch ?
    And also, if i’m only using 6X12 volts will it be viable anyway (don’t plan going more than 40mph and only in-town, flat terrain) ?

    Of course, i would greatly appreciate the pics !!!

    Lots of ? but, nobody in their projects will give an easy and cheap way of fitting the motor to the tranny …

    And if you have pics of this particular aspect of your project, i’ll take them with joy …

    thanks much for your help ( your project actually got me started with mine …)


  91. — James May    Jun 16, 2007 19:13 PM    #

    Hi John

    Look what I have found on the austin ev trading post

    adaptor plate for firefly

    I hope it’s still there!

    I am sure I have seen new adaptor plates for this vehicle on the web so have a hard look before you make one.

  92. — James May    Jun 16, 2007 19:57 PM    #

    Gosh, I’m on a roll!

    new adaptor plate for firefly

  93. — John    Jun 16, 2007 23:51 PM    #

    I’ve already seen those thanks… Call me old fashion but, for me, building things from scratch is the best part of the project !

  94. — John    Jun 18, 2007 16:17 PM    #

    Forget about the coupling: just read your answer on the first blog on LoveJoy products…

  95. — Dr. Larry    Jun 26, 2007 07:50 AM    #

    Hello John
    For me I went and bought a new clutch plate and then cut the spline out of it and then took that to a friend who had a metal lathe and he turned it to just fit inside the love joy connector. Then my frined Ron cut groves in that and drilled through the love joy and tapped and died the drilled holes and put set screws down into the groves. Then put another set screw on top of that to lock the first ones in place. This was done in three places around the love joy. For sure fire result drill even into the spline and run a set screw into that and I know it won’t move on you. Hope this helps.

  96. — John    Jun 26, 2007 10:35 AM    #

    Thanks Larry. That will help a lot ! I will receive the motor in the coming week and still planning on how to fit everything upfront.


  97. — Johnny Wang    Jun 29, 2007 17:39 PM    #

    Hi Larry,
    You have given me hope with your successfull project! I have one question if you can find the time.

    What is the amp hour rate on your wally world batteries? I have one in my boat thats 115AH. Are yours 115AH also?

    thanks a bunch

  98. — Dr. Larry    Jul 06, 2007 20:03 PM    #

    Yep they are 115 amp hour batteries. I was sent two Ultima batteries from their company for bench testing and their very best battery would not compare to the one from Wal Mart, as it only has a capacity of 75 amps and was 20 lbs heavier. What a wast. But here is something I bet you didn’t know, I didn’t either. Ultima Batteries makes Wal Mart EverStart Batteries. Ain’t that a hoot?

  99. — Dr.Larry    Jul 14, 2007 18:11 PM    #

    Update. No Gas 2 has been upgraded from 72 volts to 84. Yep added anoher battery in series. A test drive has determied that the range is been bumped up a few miles but most of all it preforms much better when the batteries get low,I guess that is due to the higher voltage. I had my friend Ron over with his laptop and reprogramed the controller for 40 volts over. So far so good!!
    nothing smoked

  100. ohio    Jul 14, 2007 18:19 PM    #

    i test ran mine today cant wait to drive it

  101. jerry Halstead    Jul 15, 2007 08:05 AM    #

    Congratulations Tim!

  102. ohio    Jul 16, 2007 21:30 PM    #

    ok drove it 37 miles to day man its fast runs great

  103. — Mark A Jeffers    Jul 17, 2007 02:50 AM    #

    Dr. Larry, you have a 48 volt controller?

  104. Gavin Shoebridge    Jul 19, 2007 01:38 AM    #

    Larry, what acceleration difference have you noticed since upping your voltage. Do you know what your 0-35mph time is now?

  105. — Dr.Larry    Jul 27, 2007 19:57 PM    #

    No Mark,I have a 72 volt controller. Gavin—I never timed it but let me tell you it is very quick. I like to show off at stop lights.

  106. — Mark Jeffers    Jul 28, 2007 00:47 AM    #

    Sorry Dr.Larry, I must have been delirious.

  107. Gavin Shoebridge    Jul 30, 2007 16:47 PM    #

    Hehehe, good for you Dr L!

  108. — Dr.Larry    Aug 12, 2007 17:27 PM    #

    Our big car show here is on the 18th “Cruzin the Park” This car has been a big hit for the past 4 year. I am also looking forward to the labor day parade in Cedarville, Ohio (birth place of labor day)as will be the third year for that one. Thousands upon thousands of people get exposed to the car there. I enjoy showing off the car as much as I do driving it. I take the car to at least 20 car shows each year. This year at the Clark County Fair Grounds where a car show was being held, people on both sides of me moved because everyone was wanting to see the electric car and was not paying any attention to their restored classics. he he. So polish up those EVs and get them out there in front of the public. When people ask me how fast will it go I always respond “fast enough to get a speeding ticket.

  109. ohio    Aug 13, 2007 20:24 PM    #

    hi please email me with the next car show you go to i just bring mine to.

  110. — Dr. Larry    Aug 14, 2007 09:10 AM    #

    Ohio—The next car show I plan to attend will be here in South Charelston, Ohio on Saturday 18, 2007. The park is located on US 42 at the north edge of town. The show starts at 4 pm and runs to 8 pm. A pork chop dinner is offered at the shelter house along with prizes, 50-50 drawing and a DJ. playing 50-60s music. Hope to see ya there.

  111. John    Sep 06, 2007 22:49 PM    #

    Unfortunately I had already purchased a Zivian 120V charger before I looked here which set me back AU$2000 which is a pity. One thing I noticed when it arrived is that the rating is 240v 19A input, 120V 18A output.
    Besides something looking rather wrong with the maths (by my calculation there is a 50% power loss somewhere), I’m going to need to put in a 20A power point. This isn’t a problem at home however it sort of precludes me plugging in at work or other normal power point (Australian points are normally rated at 240V 10A max). After reading everything here I’m tempted to put 11 (one for the accessory battery) small charges in as well so that I have two charging circuits, one high capacity for full charging and a second to give a top up when I’m out and about. Might even mount the high capacity charger on the wall at home and just leave the smaller ones in the car. Anyone see any potential problems with this setup?

  112. JohnW    Sep 06, 2007 23:15 PM    #

    PS I’m not the same John that has posted earlier in on this page. I’ll have to change my name :)

  113. — Dan P.    Sep 07, 2007 02:15 AM    #

    “Anyone see any potential problems with this setup?”

    Not that I can think of as long as you don’t try to charge with both systems at the same time.

    The regulated small chargers might pop their fuses if they are 10A being back feed 18A so maybe the use of a double throw switch placed inline to isolate which charging method you are using at the time ie. “High/Low”.

    Just an idea but I’m not a electrician.

  114. JohnW    Sep 07, 2007 03:07 AM    #

    Good idea, or I might build some sort of cut-off switch on the cover of the high current connectors.

    I just got a message back from the supplier of the main charger, they said that it might peak to 19A but a 15A power point should be fine, still might be safer to run with the two charger setup though.

  115. — James May    Sep 07, 2007 07:47 AM    #

    I have an older Zivan K2 charger and it is adjustable for max current. It seemed to work OK pulling in excess of the 13A rated fuse for a little while. i.e. I haven’t blown any fuses.

    I regularly run individual car battery chargers (at least on some of my batteries) at the same time as my Zivan charger. This seems to work OK but you can confuse the Zivan charger which thinks that batteries are already charged when thay aren’t.

  116. JohnW    Sep 17, 2007 03:24 AM    #

    Thanks for that James. I’m going to get myself 10 cheap chargers anyway. Looks like I’m going to have a bit of a delay getting a potbox and contactors and I don’t like the idea of the batteries sitting there slowly discharging so rather than 1/2 wiring everything up I’ll chuck the batteries on separate chargers while I’m waiting.

  117. — James May    Sep 17, 2007 08:14 AM    #

    Hi John
    Yes, that seems sensible. I’ll keep an eye on your site.

  118. Gavin Shoebridge    Sep 18, 2007 00:45 AM    #

    John, what do mean by a delay in getting your potbox and contactors?

    Are you out of cash (like me) or is there a backorder on those things now?

  119. JohnW    Sep 18, 2007 01:40 AM    #

    Just having trouble finding a potbox for the ZAPI. Not many places here in Australia that sell that sort of thing and so far I haven’t gotten an answer from a couple of websites in the US that I have asked questions of. I’ve got 2 contactors organised but the third is going to be about 6 weeks before it gets here. If I can get the potbox I’ll hook everything up without regen to start with and rewire once the last contactor gets here.

  120. JohnW    Sep 18, 2007 01:45 AM    #

    Actually a quick question. Does anyone know much about the potbox’s? My understanding is that they are basically a standard variable resistor, bit like a volume control just with a bit of hardware to connect the accelerator cable to. Anybody ever tried making one of these up? If so is the variable resistor linier or logarithmic?

  121. — James May    Sep 18, 2007 07:28 AM    #

    I wouldn’t mess around if I were you. I think that the pot boxes are 5K linear rotary variable resistors with added switches but if you remember just how delicate most variable resistors are, I’d hold out for one which is designed to survive a right foot.
    You’d be OK testing with normal variable resistor but do you want one to go “crackly” when you are reversing?
    You probably don’t need a Zapi potbox but it be as well to find another fork lift one or similar.

    There’s a little bit of mentioning of pot boxes on this old forum: http://www.mail-archive.com/ev@listproc.sjsu.edu/msg06755.html

  122. JohnW    Sep 18, 2007 07:36 AM    #

    Ok thanks, I’ve been looking at the PB-6 but from what I can see in the pictures (can’t find any other info) it looks like a 2 wire and the ZAPI is set up for a 3 wire.
    I’ll check out the link you provided.

  123. JohnW    Sep 18, 2007 19:53 PM    #

    Ok got my answer, the PB6 is a 3 wire pot but only two wires are connected, you just have to open it up and solder a new wire in.

  124. darin    Sep 19, 2007 13:59 PM    #

    I guess I will fess up at this point and say that the pot we used in the ForkenSwift is a $3 Radio Shack item that we retrofitted into the potbox that came with the forklift (its pot wasn’t compatible with our golf cart controller).

    The alternative was a $29 US Curtis pot – which I was glad we avoided for 2 reasons: 1) someone more experienced than I told me their quality is not that great, and 2) I shorted it out last week, ruining it. An additional $3 for a Radio Shack replacement was much easier to swallow than $29…

  125. — KEN    Dec 17, 2007 18:13 PM    #

    Hello All,
    I left some questions on the first page of this topic if anyone can answer them. Thanks, and btw Dr.Larry, how thick is your adapter plate?

  126. — Paul Holmes    Feb 09, 2008 23:08 PM    #

    Dr. Larry, you have had a major impact on me, showing that an affordable EV could be built that really works. A couple questions to whoever wants to comment: Is it difficult to deal with a car that has airbags when converting it to an EV?

    Has anyone any knowledge of Kelly controllers and other parts that they are selling at kellycontroller.com? They are about 1/2 the price, and they even have controllers that go up to 144v, but just aren’t listed for sale on their site. It’s pretty new. I think they are Chinese.

  127. JohnW    Apr 23, 2008 19:34 PM    #

    Thought I’d drop in and give an update on my conversion. I almost got their BUT. I didn’t realise that the ZAPI used full pack voltage to drive the contactors and I used ones with 12V coils. To cut a long story short I cooked one contactor and the logic board :( I think I’ve narrowed the damage down to a track, 3 diodes and a driver transistor. Hopefully I can repair it otherwise I’m up for a new logic board or controller.

    Anyone know a good place to get a login board for the ZAPI H2?

  128. — James May    Apr 24, 2008 07:11 AM    #

    Hi JohnW
    I know a good place in the UK if that’s any help.
    I have a Zapi H2 with a blown logic board too. A similar thing happened to it, a short on the contactor coil wires has destroyed the contactor driver power transistors. I was told by the technicians at Electrofit Zapi that new logic board would be available for 232GBP + labour. My current plan is to use another controller so mine is sitting there unfixed.

    I don’t know the equivalent contact in the US.

  129. — James May    Apr 24, 2008 07:13 AM    #

    Actually, don’t quote me on the price, it’s from memory.

  130. JohnW    Apr 24, 2008 21:27 PM    #

    Thanks James but I managed to fix it. Replaced 3 diodes, a power mosfet and a bit of jumper wire for the burnt out track totaling $5 it’s now working, a lot better than $999 that a local place quoted me. In fact I got everything together and took the car for a short test drive last night. IT WORKS!!!!!!!

    If your fault is the same as mine it isn’t hard to fix, I can run you through it if you are comfortable with a soldering iron, particularly if the logic board is going to be replaced anyway.

    And thanks to everyone here, for all your help and advice, I now have an EV that runs under its own power. Just need to tidy a few things up and then get it inspected and I’m on the road.

  131. — James May    Apr 25, 2008 08:18 AM    #

    Hi JohnW
    Mine’s much more badly damaged unfortunately. it blew a small ragged hole in the cirbuit board. I have replaced several MOSFETS and diodes before though, to rehabilitate my Zivan K2 charger when it let go. It’s very satisfying, isn’t it!

  132. Jerry    Apr 27, 2008 11:14 AM    #

    Congrats, John! Great to hear you managed to fix the logic board yourself, too.

    Do you have some pictures/links that you can share?

  133. JohnW    Apr 27, 2008 20:43 PM    #

    Will have shortly. Going to take a bit of video and post that up.

    Test drive went really well, broke traction in 2nd :) Only problem now is that the back battery box isn’t bolted down yet and has a tendency of wanting to join me in the front seat if I break to hard which with 400kg of batteries isn’t the best of things ;).

  134. JohnW    Apr 27, 2008 20:45 PM    #

    I do have a couple of old pics on my website at


  135. JohnW    Apr 28, 2008 09:17 AM    #

    If anyone wants to drop me some details I’m setting up a map of EV’s and conversions. I mainly set it up for Australia ones however international conversions are also welcome, people will just have to zoom out a little to see them.

    If you want to be added then send me the following details

    Your Name
    Vehicles Name
    Vehicle Details
    Stage (Planning/Just started/Almost done/Complete/Inspected and roadworthy)

    Also if you have a website or any other details you want listed against your vehicle.

    Unfinished and conversions in the planning stage are welcome as are international conversions.

    You can see the map on my website at the below link


  136. — EVdude    Aug 01, 2008 19:28 PM    #

    Dr. larry,
    did you use fiberglass body panels on your metro. I posted this question on your original article but so far no one has answered.
    P.S. my Probe is a 94 not a 90 like the seller told me. i found the manufacture date on the door panel and it was manufactured january of 94.

  137. — Dr.Larry    Aug 17, 2008 09:49 AM    #

    I am using the stock metal panels on the car. The total wt# is 18,880 that is a few hundred lbs less then when it was a gas car.

  138. — EVdude    Aug 17, 2008 12:16 PM    #

    OK thanks for the info. if you really wanted to save some more weight then google how to make fiberglass body panels. if you don’t want to do it yourself then drop it off at a body shop. I plan on doing this to my probe to lighten it up. i also plan on using aluminum sheets to streamline the bottom of the car.

  139. — EVdude    Aug 17, 2008 12:32 PM    #

    thanks for doing your metro conversion. if it hadn’t been for this i would have never been able to afford my own conversion. I found two double belt engine pulleys in my shop and plan on getting rid of the tranny(well somebody else had bought it off of the car before i bought it at the junkyard) and using these because they use 2 1-inch thick belts and the drive shaft can be taken apart to slip these onto it(one looks like it has a hole large enough to fit the driveshaft, the other is about 15/16 diameter which is 1/16 larger than the shaft diameter of my motor). One pulley is about 1.75 times larger than the other. this is the one that will mount to the motor.
    Keep your fingers crossed and lets hope that it works.

  140. — DanP.    Nov 07, 2008 15:36 PM    #

    Hey Dr. Larry,

    Here is a new EV solution for powering a Metro! http://www.youtube.com/watch?v=wneCRRb0Y5U