My Nissan Leaf Forum

Yeah, charging via regen towing is an old idea that works, but is a bit hard on the car.
There are some who have made gasoline powered "pusher" trailers so that you can temporarily add a "range extender" too.
Neither of the ideas are anywhere near mainstream right now.

I would second what Herm said earlier on this:

Trying to use battery power from one LEAF to drive regen to charge a second LEAF has got to be terribly inefficient. You could get both cars a lot farther by towing slowly in neutral.

However, do be aware of the warranty, which Herm also alluded to:

I believe in being nice to other LEAF owners, but you are not going to talk me into voiding my power train warranty by towing your LEAF. I'll be happy to call the free towing service for you if your cell phone isn't working.

Ray

Join Plugshare and you'll never be more than a few miles from a charging dock. Well, that's the theory anyway.

Just don't cause damage, and there will be no problems:)

Again, for people who treat car as a black box with steering wheel - towing is prohibited! You have to know what you are doing. And even Nissan doens't say towing is not allowed - they say if you damage it - they aren't paying. Fare.

Why I would use some regen, if being rescued - get some buffer to get up the driveway, or probably up few blocks from main road, so I could let other person go. I agree on total inefficiency of such charge - i'd estimate 30% of efficient, vs when towing in neutral (lossed on conversion, charge and discharge)

i think the original idea behind the OP was wondering if there was a way to transfer some charge from a fully charged Leaf to a depleted Leaf. this towing conversation is ridiculous.

In the Netherlands. You can see the video on Youtube: http://s.meulie.net/n15dtz

Something like that would be fast relatively simple. The problem is that a mostly fully charged battery has the same terminal voltage as a mostly depleted battery. There's no voltage to push significant current between batteries.

The answer for this is to include a voltage booster that also handles large currents. The voltage boost might not need to be very great.

Something like this already exists for 12V cars. A special cable plugs into the cigarette lighters of two cars (one needing a jump, the other fully charged). This "cable" includes a voltage booster to raise the 12V from the source battery to 13.8V to charge the dead battery.

The LEAF's Battery Pack is about 395 volts when full, and under about 300 when near empty.

It only takes about a 10v surplus to drive 50 amps into the pack, and a drop of maybe 10v to supply the 50 amps from another pack.

So, approximating that a 20v difference might make 50 amps flow, a 100v difference might make 250 (or 1000) amps flow, way too much to be healthy for either battery.

Now, adding a 2 ohm (5000 watt) resistor in series between the battery packs might limit the current to something like 40 amps ... which might actually make the "rescue" workable.