I’m looking to build a simple solar system to charge my two electric cars away from the house. This will be a stand alone system. No grid connection, no connection back into the existing domestic system. (Domestic system is hybrid 7kw solar, 48v battery bank with a tie to grid). I am considering expanding a small system I built to power my workshop. (2 x 450w panels, a cheap 3kw inverter and 2 x 245ah 12v batteries). I think eight 500w+ panels will be sufficient for the project. . Can anyone give me some recommendations on the plan. Should I just ignore the bits I have and start afresh? Ideas about a good simple car charger? I have a myenergi Zappi for the house which is very unimpressive and expensive. And a cheap 230v plug in thing that came with my KIA that is stunning on the KIA but won’t charge my Peugeot. Do I even need batteries? Appreciate any advice. Location Spain.
There is a very nice and usefull calculator in Clean Energy revieuws. Fill in all your parameters, type of EV how frequent and how many you drive etc. also in winter…
Fill in the nr of solar panels that you have or can place. Suggest at least 12 - 15.
Most EV’s require a minimum power of 6 amp at 230 V. = 1500 watt. Below that (winter?) no charge so make sure you have plenty of panels.
Better (but more costly) is a LFP battery of say 15 kWh as a buffer. then you can (trickle) charge the battery with the PV panels. And you can charge the car whenever you want (night?). Victron has very nice solutions for this, e.g. the Multiplus RS with built-in solar MPPT regulators. This device can charge you car with 6 kW.
Sorry, there is absolutely no way you can charge an EV using two solar panels and 2 x 12V batteries. To charge an EV at the minimum rate of 8A (1900W), you will want to install at least 8 panels and use a 48V battery system with a decent 3000W inverter (4kVA min). It sounds like you need to do far more research and consult someone who knows more.
Thanks Jason, I think you must have missed the beginning of my message. I said that I have some parts, namely a 3kw hybrid inverter, a small 24v battery bank and two panel. To this I plan to ADD 6 more 550w panels to bring output up to circa 4kw.
Yes, sorry. I misinterpreted your message. If you’re building a small system with 8 panels and want to use the 3000W inverter, you won’t have enough power to supply a dedicated (wall mount) EV charger. The most it will be able to power is a 10A (2400W) wall plug-type charger, but I’d invest in a 15A wall plug charger so you can use it on a larger system or take it on road trips. In my experience, those cheap 3kW inverters can barely supply 2800W continuously for more than a few hours.
Also, you definitely need a battery as the inverter cannot support the load without a regulated DC supply from a battery.
Thanks Jason. Understood. I already have a 16 amp plug in charger which works very well on my PHEV but my super fussy Peugeot e208 won’t have anything to do with it for reason I am unable to fathom. I was hoping to find a charger that would shut down automatically when there was less than 1400w coming from the panels and I don’t think the plug in type will do that sadly.
Spain’s a great place for trying this — plenty of sunshine to play with. Eight 500 W+ panels will give you around 4 kW peak, which in summer could mean 20‑25 kWh a day if the weather plays nice. But even that can go quick with EVs. A small top‑up might be fine, but if you’re thinking “full charge”, you’ll run out of sunshine fast in winter.
You could run it direct‑from‑solar with no batteries if you’re happy to only charge in the middle of the day, but honestly it’s a pain in real life. Even a small battery bank helps a lot — think of it as a buffer so the charger isn’t starving every time a cloud comes over. For EVs I’d be looking at 48 V LiFePO₄, 10‑20 kWh usable if budget allows.
I wouldn’t bother trying to scale up your workshop kit for this. Two 245 Ah 12 V batts and a 3 kW inverter will get flattened in no time by an EV charger. I’d keep that system as‑is and start fresh with a beefier inverter (5‑7 kW) and proper battery bank.
On the charger side, skip the Zappi — overpriced for what you want and you already said it didn’t impress. The portable KIA one sounds like a gem but won’t work on the Peugeot, so maybe look at a basic adjustable‑amp EVSE (there are plenty online) so you can match it to whatever the inverter can supply without tripping it.
In short — keep the workshop system, build a dedicated off‑grid EV charging rig: ~4‑6 kW solar, 48 V+ battery bank, 5‑7 kW inverter, simple EVSE you can dial down if needed. That’ll keep you happily topping up both cars without touching your house system.