Going to leave my car in an outdoor parking lot for a week, and it made me curious. Can I attach a small solar panel (<100W) to the inside of any modern EV such that there is a higher state of charge when I come back?

  • Welcome to Motor Vehicle Maintenance & Repair! You state "any modern EV", which makes this a VERY broad question. Every EV manufacturer, I'm sure, does their charging differently. Saying "every" as a prerequisite makes it highly unlikely. Secondly, the input rate of EVs is very high in comparison to the "<100W" you're suggesting. Might the 100W do something? Sure, it might provide another 100 feet of travel in the vehicle (if it can take the power at all). Realistically, it's not going to do much, though. Jul 28, 2022 at 17:44
  • @Pᴀᴜʟsᴛᴇʀ2 “any” means “does there exist?” so I’m just looking for an example, not a list. Jul 28, 2022 at 17:51
  • Some new Hyundais have solar roofs, which have 0.2kWp, and can add 2.5 miles of range per sunny day. Not much, but also not nothin’. Who knows if the added cost, weight, and complexity are worth it, though! techcrunch.com/2022/03/23/hyundai-sonata-hybrid-roof Jul 28, 2022 at 18:17
  • Fisher Ocean has a solar roof, which is claimed to add “up to 1,500 … miles per year” (4 mi/day) fiskerinc.com/ocean Apr 13, 2023 at 13:42
  • Back when Toyota came out with the Prius, there was supposedly an aftermarket solar panel you'd glue to the roof of it to give you an extra 10% range. Didn't hear too much about it for too long, though. I thought it would be ingenious to have something like that. I'm surprised Tesla hasn't incorporated some of the solar cells to such a task on their EVs. If you could add an additional 10% of range onto them by just adding the cells, seems like it would be a huge win. Apr 13, 2023 at 14:21

3 Answers 3


A Tesla supercharger maxes out at about 250kW.

Your 100W solar panel is a 250th of the power, so assuming you can work the adapters required (unsure if this is possible - probably need to create an inverter circuit) the Tesla-quoted 15 minutes for 200 miles of charge would be just under 3 days for 200 miles of charge.

Realistically, it isn't going to happen. You need more current! You need more power!

  • Why do I need more current or power? The car is going to be parked for multiple days. Taking multiple days is, in fact, the whole point of the question. Do people only charge Teslas at a Supercharger, or do they also charge at home on a 1.8kW circuit? Jul 28, 2022 at 17:50
  • remember, whatever circuit you build will have losses - you can't just "push electrons in" - you'll need to build something to present the charge in a way the car can accept
    – Rory Alsop
    Jul 28, 2022 at 17:55
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    The charging plan Rory states assumes 100% output from the panel for the duration of "just under 3 days", which is unrealistic. You'd get that much power over 3 days worth of charging, which could take DAYS to complete. You also have losses in the vehicle while it's just sitting, due to the systems used to maintain the vehicle. I mean, I walk by some Telsas in the garage at work and they light up. The sensors which stay active to detect these things and then what it takes to actually light up the vehicle all incur losses. Jul 28, 2022 at 18:00
  • You need to talk about KWH not KW. A Tesla car stores 50-100 KWH of power. A 100W solar panel makes 0.1 KWH/hour. Aug 2, 2022 at 1:52

In theory this could be done. But in practice there is no way to plug in a PV panel to any currently made EV. I suppose if you were creative enough you could design and build an interface but it's not going to be trivial.

So the answer is effectively NO, you cannot do this.

Even if you could do it, the contribution of your 100W panel is going to be insignificant. The smallest Tesla battery is a 50 kWH unit and I'm not sure they actually make any of those. So assuming you are someplace very sunny and you get 12 hours of sunlight that maxes out your panel at 100W. That will give you 1200 WH of energy every day.

That amounts to a paltry 2.4% of the total charge in the battery. Now in reality there is nowhere on earth that gets 12 hours of "noon" sunlight so you are more likely going to be in the range of less than 1% charge per day.


Honestly the answers above are quite good but I mean to answer this in a more general matter and say that there are hybrid cars specifically designed with this idea in mind. You can see one example here https://www.eproinn.com/en/life-save-en/ but you have to realize that the batteries of a hybrid vehicle are significantly smaller than an ev and there a lot of circuits and design specifications under the hood to enable a charge boost with lets say 8 hours of sunlight.

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