LCR wrote:Where do you live that 4 panels would provide any sort of fuel? Not counting charging losses a 320w 4 panel system would give you 1700kwh here in the south, even at 4 m/kwh that would be 6800 miles. My Leaf averages 3.6 and my Tesla closer to 3 m/kwh. Lets assume the highly optimistic 4 miles/kwh because it makes numbers easy. you'd need 3,000 kwh to drive your 12K miles, that would be a 2.5kW system here in Texas and 8 panels, twice what you think.
I was an off-the-cuff estimate, but here's my math:
- The 235-Wp 60-cell panels on my roof each produce a third of a MWh of electricity each year. If I scale that by 6/5 which is the per-panel ratio of production I see with Tony Williams' system in San Diego versus mine and scale up to 325-Wp panels I come up with a per-panel annual production (AC) of about 550 kWh/year.
- Four of such panels will produce about 2.2 MWh/year.
- We get an efficiency of about 5 miles/kWh in our LEAF. (That's fairly high, but others here report higher numbers.) We know that L2 charging efficiency of the LEAF with the 3.6 kW charger was 91%
. Since there is a fixed load of about 300 W for cooling pumps, I expect the efficiency of a 6.0 kW charger is closer to 95%. That gives about 4.75 miles/kWh.
- I'm going to assume the magic of net metering to allow me to use all of the AC energy that I produce on my roof.
2200 kWh * 4.75 miles/kWh = 10,450 miles.
I should have said five panels to cover 12,000 miles (or even 13,000 miles) with current technology.
But your point is taken: It is hot in places like Texas or Arizona, so PV production is likely lower. And of course driving styles and vehicle type do affect consumption. So YMMV.