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Is it practical to think you can charge a car like this totally off-grid? How long does it take to charge the car on solar and does it take a huge solar panel to charge it?

There are folks who do this, although much depends on how much power (i.e. range) you need in a given day and what your alternative power options are capable of producing.

A fellow up our way who was a professor at Dartmouth and commuted each day with an EV put a huge array of solar panels on his barn roof. Rather than feed the EV, he sold the power to the power company to “offset” what the EV needed each night. In this way he didn’t have to store it in yet another set of batteries to feed the EV each night.

We’ve had a couple articles featuring Peter’s Solar Electric Van (and Part II). Peter has done some fantastic work and documented it quite well on his website.

There’s quite a bit of money and custom electronics in his setup and yet it isn’t able to rely solely on wind or solar for power.

My suggestion is to take the “home” approach where you mount the solar and/or wind panels in a fixed location optimized for harvesting sun and wind all day. Sell the energy back to the electric company to offset what you’ll need to charge the EV. Don’t add the additional weight, cost, and complexity to your EV in an attempt to snag a few watts with solar.

If you are looking for a Solar Car Charger, stop by Café Electric to see Otmar’s modified pocket inverter.

Comments 2
  1. — Andrew    May 30, 2007 04:24 AM    #

    As far as powering or charging; I would somehow install a 12v alternator with a voltage regulator inside the car wheel well under fender. Depending on the room I think I would be able to fabricate an inflatable rubber wheel (open to suggestions) to the alternator pulley and make contact to one of the tires (could possible put one on all four, yes it would need flex). As the car is mooving it would be charging/powering.. It would take some trial and error for wheel diameter ect.. Just a thought..

  2. — James May    May 30, 2007 08:21 AM    #

    Hi Andrew,

    If you think about it, this isn’t a good idea. You would be charging the main pack from itself. I hope you didn’t mean this!

    If you mean to charge the SLI (starter, lights, ignition) battery from the main pack, you can do it with an alternator, but you are probably better off using a dc-dc converter, I think, for reliability, or charging the SLI battery whenever you charge the main pack.

    If you mean to use the rubber wheel alternator to recharge only under conditions of coasting down and braking, there are better ways to do this as well involving the main motor.