diy solar

diy solar

DIY System to charge 2 Tesla Cars - what is best value?


New Member
Oct 3, 2023
Clearwater, Florida
I am new to solar but have been thoroughly involved reading about options to charge our new electric vehicles.

We live in West/Central Florida and get plenty of sun. HOA limits the number of panels on the roof due to being visible from the street.

Therefore, I am interested in a system that would mostly only handle charging two cars (not the house). 2 Tesla Model Y's.

I am considering our back roof and a pergola over pool for the panels.

One vehicle drives 50 miles a day and charges every other. Second vehicle uses half that.

How many panels recommended? (my calculation was about 12)
What is the most cost-effective battery option?

Is there links to current available equipment to explore this DIY option?

P.S.: I will have the hire an electrician/electrical engineer to make any build, I just want to see what the components really cost on a conservative basis. Not looking for name brand like Tesla build.
16-400w panels at 70% production for 5hrs/day is 22.4k
At 4kwh/mile that put you at around 80-85 miles per day of range
If you level 2 charge you will need a split phase inverter. With enough capacity to charge at your desired amps. Say maybe a solark 8k, 12k or maybe a more budget oriented option
Then probably the equivalent of 2-3 eg4 power pro batteries
At least in napkin math is how it would make sense for me
i charge mostly overnight as we are only home from about 9pm - 8am.

This will be the big challenge.

In order to charge at night from the solar power collected during the daytime, 100% of this power will need to be stored in a battery pack. Not just a small one.

Most likely there won't always be sufficient power collected, so the pack will also need to be charged via the grid ( at least sometimes )


In many parts of the US, the price of electricity varies depending on time of day or during peak vs off peak related aspects.

So one approach would be to try to offset the total cost of your electricity by feeding the solar power back to the grid during peak hours (when it has the most value ) and charging from the grid overnight (when electricity is often the least expensive )

In CA, peak hours are ~ 3 - 8 pm so anything generated really in the afternoon - especially late afternoon has the higher value. The exact value can be complicated to figure out but locally the difference in pricing can be easily 5x under some plans.
I live in NE Florida and our power company FPL has an EV program ( ) for $31 / $38 per month. They can also install a charger for you. I have my own solar (carport with its roof made of solar panels). Anyway, check to see if your power company has a similar EV program. Frankly, $31/month isn't bad for unlimited use and you don't have to mess with having your own system.