sharkmobil
Posts: 9
Joined: Tue Jun 02, 2015 10:06 am
Delivery Date: 10 May 2015

Solar charging Leaf

Tue Jun 02, 2015 10:31 am

Hi, I've combed the forum for similar ideas, all I found was an attempt to charge lead batteries in the trunk, then use those batteries for Level 1 charging while parked. Incredibly inefficient, no wonder it didn't take off.

Since I've read somewhere that Leaf has a block against moving while charge is happening, I'd like to try interfacing solar panel with Leaf's regenerative circuit. Are there any hardcoded limitations (like reverse current sensing/brakes actuating) that might prevent me from doing this?

So far, I have found a panel to occupy Leaf's roof (300W 1956mmx991mm) and the way to mount it. Need to find a good DC-DC boost converter (10 fold) and a way to interface with Leaf's internals.

1.5kWh a day I figure is not a lot, but will pay for itself over the three years timeframe at $0.20c a kWh prices, having accumulated couple of full charges a month without the hassle is the added bonus :)
2015 Silver S

Slow1
Posts: 486
Joined: Fri Jul 11, 2014 3:15 pm
Delivery Date: 28 Jun 2014
Leaf Number: 425010
Location: Eastern MA, USA

Re: Solar charging Leaf

Tue Jun 02, 2015 12:43 pm

Keep us posted (with pics). One concern I would have is that anything mounted on the outside of the vehicle may add more drag than it is worth - i.e. energy used to overcome additional drag would exceed value of energy collected.

Perhaps explore ways to placing panels in trunk and pulling out when stopped as a solution....

When considering 300w panels, understand that is the peak in ideal conditions which doesn't happen for very long in the real world of use. Included in this is an assumption of nearly perpendicular angle to the sun. Being mounted on roof of the car you won't get this much (can't very well put a tracking system on there eh? - see wind resistance above). Thus I think you will be lucky to get 1/2 of your estimated collection so maybe 750Wh/day.

So, if you collect 750Wh/day and get 5 miles/kWh on average, that would give you about 4 miles of added range. Now, if this drag reduces you to 4.5M/kWh, then you will lose all the benefit in about 10kWh of use - so you break even at 1/2 charge used but then lose the rest of the charge. Even if you were to get your anticipated full 1.5kWh/day, that means on a full 20kWh burn (full use of the Leaf) you would break even... Not sure the payback will be as quick as you suggest.

Too many assumptions here of course - please challenge them and post results of experiment as it will be interesting. I'd love to be wrong here.
2013 S with 6kw upgrade (Black)
MFD Date 12/13

User avatar
davewill
Posts: 4867
Joined: Thu Mar 17, 2011 6:04 pm
Location: San Diego, CA, US

Re: Solar charging Leaf

Tue Jun 02, 2015 5:40 pm

There are endless posts on this subject on the forum. Seems to come up regularly. The consensus is always the same, you won't get the results you expect, and would be better off putting that panel on the roof of your house, but...PLEASE go ahead and do it. Then we'll have someone to reference when the next guy has this brainstorm.
2014 Rav4 EV, Blizzard Pearl White
2011 LEAF SL w/QC, Blue Ocean, returned at end of lease

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