Solar panel charging...

At a $30/month savings, you will have a very long payback period. The temporary storage battery will likely have to at least 50% bigger than the car's traction battery to start. Then you need to size the solar arrays to fully charge that on the shortest day of the year if you want this to work year round.

I would just pay the $30/month and be done with it and skip the storage battery.

Note that if you are pushing solar power to the grid by day that will offset some of your nighttime charging cost. I would think that's more than $1 a month.

 

If your state has a net metering policy inplace you don't need battery storage. Look it up online. You could start small by using Enphase micro inverters if you are handy. They convert power to AC at the panels. Start with four 335watt Panasonic Hit panels. 20 amp 220 breaker. Then build up from there.

I have 10.275 kwhp installed of solar panels now. Payback time 6.8 years. Then 20 plus years of free power.
PM me and I will send you a link to see my setup.
My Prime is a stepping stone to a full EV.

 

The key here is that you WILL get the full benefit of whatever power your solar array generates.
It matters none, or very little, WHERE that power is actually consumed.

Home lights, refrigerator, fans, A/C, going back to the grid or going to the Prius.......same net savings (or nearly).

Obsessing about getting power directly from the solar array to your Prius will be a HUGE MISTAKE.

 

If you have net meter like others have suggested, it does not matter if you are charging at night or during a day. As long as your solar panel produce on average more than 6kWh/day of electricity, you are getting free electricity to charge your PRIME. AFAIK, setting up battery storage for solar panel is too expensive currently to be economical.

 

Arizona net metering FAQ
Net metering in Arizona - Wikipedia

Not very good rates.

 

just use your solar for other things around the house. the expense and headache of trying to accomplish this will far outweigh 30 bucks a month.

if net metering is a poor financial choice, don't get more panels than you use on average

 

what size battery would you need to make an effective dent, something like a tesla power wall?

 

A Powerwall is 6.4kWh, so one will cover a Prime's charging. They are almost $8000 without installation.

First look for ways of shifting electricity use to peak solar production. I'd try hypermiling the AC. Have it cool down the house below your normal set point before 3pm so it can be shut off during the higher rate. Maybe the same can be done with hot water by using a timer. Some washers and dryers have a timer function to have it start later. Same with ovens, but I'd be hesitant to have one on while away from the house.

 

I did that in my latest house.
Turns out it isn't worth the money and minor hassle.
A modern well insulated water heater runs very little when no water is being used.
If you have a really OLD electric water heater, your money would be better spent getting a new one.
I turned mine completely OFF for 3 days while I was gone.
When I returned the water was still on the high side of warm.

 

Why not add a solar panel roof / factory option or engineer one and add it on your own to charge you batteries ...

 

great idea! please let us know how it works out

 

How many solar miles per day are expected in Dubai? Or in Japan?

Past proposals just haven't produced enough daily driving range in most climate zones. It has been more efficient and cost effective to put solar modules on a building's roof, plug the car in to the wall to take what it can, then send the rest to the regular power grid.

Less expensive solar modules, mounted in a better location and aspect, collect more total energy, and all of it gets used by somebody, rather than thrown away when the car doesn't need a recharge.

 

I honestly think it would be cheaper /more effective to import a junked Japanese Prime with panel system than what the op is proposing

 

It’s only March and my 10 panel home system is already making enough kWh to charge our 2 Primes every day, with extra left over. Should be net zero for the year here in SoCal. $6500 after fed rebate. No battery backup. I like the idea of using the sun to power most of our driving.

 

can you re mount it onto the roof of your prime?

 

I have 2 Primes, so maybe I can mount 5 panels on each, like a sprint car.