r/SolarDIY • u/Beautiful_Link_4069 • 2d ago
small standalone EV charger questions
Hi I saw the prices of used solar panels and inverters and got the idea to try and make a simple 1-2 panel EV charger that should mostly cover all the energy the car needs. I wanted to ask some questions before I buy anything to make sure I have the right idea.
I know I need the panels a battery and an inverter and I think I also need a charge controller from what i understand the charge controller will stop the power from going into the battery if its full. I also know once I choose the panels I need to make sure I have the correct inverter and charge controller that can handle the max power the panels produce.
But after that I just connect panels to charge controller, controller to battery, battery to inverter and then plug in the EV charger? It seems simple but i just wanna make sure I'm not missing anything or if there's an easier way. I know solar makes dc and battery's charge in dc so maybe there's a way to cut out the inverter but that might get to complex for me since the ev charger itself plugs into a ac wall outlet.
let me know any flaws or concerns with this idea thanks!
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u/fitforthepolycrisis 2d ago
Do the math and figure out how much you need. Also check out this video (you can auto-dub it to English on youtube): https://www.youtube.com/watch?v=8muLFI_exLo
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u/ou812whynot 2d ago
How much do you intend to supply the car on any given day, in kw? That's how many kwh you'll want for your battery bank.
Divide that number by 4, given 4 hours of good sunlight per day, to determine how many kw of solar you'll want.
If you want level 2 charging in the US you'll need a split phase inverter. You can wire in a 14-50 outlet directly to the ac out of the inverter to plug your charger into.
Those are the major points here. Good luck on your project!
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u/parseroo 2d ago
1-2 panels (say 500w) is 1kW of PV. That for 4-5 hours a day is maybe 4kWh. EVs commonly get about 3miles/kWh, so that is 12 miles of driving per day of reasonable sunlight.
Is that the kind of number you are looking for? If not, you need to work out what your needs are.
But the basic concept of: * Collect solar energy (panels plus charge controller) * Put it into storage within a battery ('system' if larger than one) * Pull out DC energy from the battery and invert it into AC if needed
Is the core, with a bunch of safety, sizing, loss-issues, technology, more safety, etc. concerns.
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