SanDust said:
You can't realistically match charging the Leaf to solar production from a PV system. PV systems don't work this way. Even assuming you'd always be home for the right six hours a day, the rating on a PV system are for the maximum production, and you're not going to reach the maximum production for every hour of every day. In fact you won't reach it at all some days. You have cloudy days and winter days and rainy days, during all of which you won't see anything close to the system's rated output.
No you can't realistically match solar production to LEAF charging. And you really never would, just doesn't make any sense when you can go grid-tie or have an offline solar system with batteries. Either way, it works great!
What most people will do is install a grid tie solar system, where you bascially use the entire national electrical grid as your battery. Economically, in some areas with high power costs and usage tiers on a time of use (TOU) rate, this can be around 300% economically efficient - I.e. putting power in during the day on the TOU peak for a $0.35/kWh credit and chargin the EV off peak for $0.11/kWh. The numbers vary widely, but you get the idea. And it's a good thing, your solar panels help the grid out during peak air conditioning load which drives the peak where dirtier peaking power plants come online and sometimes lead to blackouts. You charge your EV at night when baseline power plants that can't vary their output need to sell the electricity at night and need more customers. Grid tie is definitely the way to go if you can, which is true of most city / suburban residences.
Remote rural residences without a connection to the electric grid need an offline solar system with batteries. The batteries store the solar energy during the day and provide electricity at night when the sun goes down to run your house and charge your EV. Very few people will need an offline (non grid-tie) system with batteries.
Consulting a solar professional or friend in your area is a great start. Figure out your LEAF electricity usage as roughly 3 miles/kWh after accounting for charging losses etc. Figure out how many miles you drive on average during the week, or however long a period you need to have a meaningful average, like if you take a long trip only once a month. Figure out how many kWh that is over what time period and give that to the Solar person. They know how do to size a system large enough to produce that much energy. Always size it a bit bigger to allow for growth in your electric consumption and/or LEAF miles driven (with ZERO emissions - excluding a little brake dust and rubber particles from the tires!)
If it is an offline system with batteries, you'll need to size the battery bank appropriately. I'd suggest large enough to get a full LEAF charge and power the house for two or three days. If you need a full 24 kWh charge of the LEAF EVERYDAY - few people will - and you have no other charging or transportation options, then you may need to size the solar system battery large enough for two or three full LEAF charges plus the house. That's a big battery bank, but it's doable and if you really are rural without the electric grid will likely still be much cheaper than getting the grid extended to your location.
The question isn't really how many panels, it's really how many kWh AC of solar generation do I need each day (or whatever interval you choose to do the math.) The type and configuration of solar panels will be determined by the other solar equipment you use, cost, availability, and enough of them to produce the required energy. The number of and type of solar panels is really a system design detail that doesn't need to be worked out until later in the project.
If you post you're intended usage / average miles driven and whether your house is connected to the electrical grid, you'll likely get more help from this forum.
Do check out solar professionals and installers in your area. New solar companies like SolarCity are offering solar systems as a lease or purchase with very little or no upfront money since they finance the system for a decade or more but the system pays for itself in less time than that. The tradeoff is that they share in your savings over that time period, so if you financed it in cash upfront you get a slightly higher return on your investment.
