Can an EV charge another EV?

Discussion of the technical aspects of electric vehicles
mike callender
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Can an EV charge another EV?

Postby mike callender » Sat Feb 17, 2018 8:27 pm

Any of you battery experts out there know if you could use, say a Tesla to trickle charge a Leaf? It would be good if I had a mass of solar panels, I could use to charge a Tesla during the day, then recharge our 3 env200 delivery vans at night. The vans are out most of the day so can't charge much direct. Could get 6 Powerwalls with 81kwh storage for about £36K or a secondhand model S for same price!

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Buzby
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Re: Can an EV charge another EV?

Postby Buzby » Sun Feb 18, 2018 9:13 pm

I’m prepared to be shot down, but I’d say the answer is no, at the moment. The current vehicles expect to be fed, not dispense their stored power. V2G (Vehicle 2 Grid) offers up lots of possibilities - and not just exporting back to the grid, but with the correct interface anything you like - your home, another EV, floodlights in a field... it becomes much more interesting. Pride of place - and no doubt why V2G had such a slow start, imagine filling up your EV with 32Kw at say 6p per Kw overnight, waiting for your white meter to change tariff, then sell it back to the grid at 3 times what you paid for it originally?!
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noahs-dad
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Re: Can an EV charge another EV?

Postby noahs-dad » Mon Feb 19, 2018 7:18 pm

I don't think you can even jump start the 12V battery on a BEV with another BEV or EV can you?

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Neil
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Re: Can an EV charge another EV?

Postby Neil » Mon Feb 19, 2018 9:37 pm

You certain can 'jump' the LEAF from another 12V system. But if the PDM is shot, it won't help much....... I do know of people who have jumped an ICE from their LEAF. The battery really isn't specified for that sort of thing, although you can fit a more capable 12V battery in the slot though.

Tesla are very much against supplying power from the traction battery back to the grid, or any load. CCS currently doesn't support it, but it is in the pipeline, which leaves CHAdeMO the only current standard capable of it. In practice a CHAdeMO equipped car could be instructed to parallel with another, which would let the batteries balance out. Not worth the effort?

The cost of V2G equipment is relatively high, so the economic benefit is likely to rest with commercial entities with large car parks who can use it to peak level, reducing their maximum demand and hence tariff. Pilot schemes are running in the UK, with the harmonics produced by both charging and supply back to the grid being assessed. No point going large scale if it destabilises the network.........

As an aside the Bollinger B1 has a 120v (Americans) outlet powered by the traction battery in the loadspace for power tools. Could be an emergency granny charger connection.

Mike, you could also scour the auctions for Cat D LEAFs, salvage the batteries and sell whatever was left for a profit. There were a couple recently for about £3k. Three would be a 70kWh battery for less than £10K, minus the value recovered from the drivetrain parts and wheels. If you have the space and time of course.......
Neil Swanson
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mike callender
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Re: Can an EV charge another EV?

Postby mike callender » Wed Feb 21, 2018 7:29 am

Thought that it may be possible to use a 3 kw inverter in the cigarette lighter socket so to speak. Guess it depends how quickly the lithium battery backs up the car battery. Could always use bigger car battery. Thought about buying a cat D one before, Neil, and chopping it up for an off road farm vehicle / tractor, but don't think I would be confident at messing about with their batteries.

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Buzby
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Re: Can an EV charge another EV?

Postby Buzby » Wed Feb 21, 2018 7:49 am

I would seriously doubt that any standard installed 12v lighter socket could take any 3Kw draw for sustained periods - that’s even before you get to the the losses incurred by the inverter itself. Even in an ICE, I’ve seen wiring put the out upstream of the inverter with the user reporting barely a few minutes use. I’d also imagine any EV warranty would be voided due to misuse - but then, it might be fun trying!
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Neil
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Re: Can an EV charge another EV?

Postby Neil » Thu Feb 22, 2018 12:27 am

Buzby wrote:I would seriously doubt that any standard installed 12v lighter socket could take any 3Kw draw for sustained periods - that’s even before you get to the the losses incurred by the inverter itself. Even in an ICE, I’ve seen wiring put the out upstream of the inverter with the user reporting barely a few minutes use. I’d also imagine any EV warranty would be voided due to misuse - but then, it might be fun trying!


Absolutely! The Aux socket is fused at either 10 or 15A, so 120W or 180W! A suitable inverter would draw probably draw most of 3kW to run the 2.4kW EVSE brick. Call it around 250A. Heavy cables direct to the battery. I can't find figures for the PDU 12V DC/DC converter, but I suspect it will be around the domestic load of the LEAF at about 400W, so say a generous 40A max. As it is part of the PDU, might prove expensive to replace?
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noahs-dad
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Re: Can an EV charge another EV?

Postby noahs-dad » Sat Mar 03, 2018 3:19 pm

I'd quite like it if a BEV could be a power source for a bit more than charging a phone or whatever. Like boiling a mini kettle, or running a mini microwave. There is much demand or interest for it, but I would certainly make use of that stuff.

mike callender
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Re: Can an EV charge another EV?

Postby mike callender » Mon Mar 12, 2018 6:16 am

You can get 180w travel kettles online, that plug in to cig socket. Can use when rapid charging too!

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Buzby
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Re: Can an EV charge another EV?

Postby Buzby » Tue Mar 13, 2018 11:42 am

I much prefer places like Abington village and Broxden, where I can have a coffee freshly made nearby!
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