Solar system to charge ONLY a Model 3 LR/AWD

[NJBlue]

Hello, 100% newbie here, looking at getting a 2025 Model 3 AWD which per Tesla, consumes about 25kWh / 100 miles. Ideally, I’d build a very small, portable solar system to charge (L2) ONLY the Tesla, because I’m moving a year or two from now and will take it with me then build a full system. Can someone please give me an idea for the smallest, cheapest system I could use for this, or whom I should ask? I could probably get by with 50 miles charge capacity since there’s a Supercharger only about 10 miles away. Don’t mean to be lazy - Tesla is offering 0% financing on the 3 so I’m not sure how much time I have for proper research. Thanks much.

 

[CVCPJared]

You said 50 miles, im assuming thats per day? Just some quick math - 50 miles being 12.5kwh. I think others have said charging is about 70% efficient by the time you go from DC panels to solar charger to inverter to AC plug to DC for your Tesla. So 12.5/0.7 is about 18kwh. Ignoring seasons, NJ is about 3.5 - 4 sun hours a day. If you only needed charging 6mo a year you could get by with less, 12mo, youd need a lot more. Let's say 4, that's 4.5kwh of panels, which is probably a little generous and ignoring panels putting out less than theyre rated. 11-12 full size 400w residential panels. And unless you are parked with the panels all day, you'll need some batteries.

I say that not to discourage you, it's a great idea, but I dont know that I would say a "very small portable system" can generate 50 miles a day in power if 12.5kwh to the Tesla battery is the requirement.

You can possibly not mount them, or get portable mounts if you have the room and are comfortable with that, that way it can still be portable, but not very small lol

 

[NJBlue]

Thanks so much for the advice! The thought occurs that it seems ironic that many solar enthusiasts buy an appliance (a Tesla) that adds significant energy consumption to their electric bill. Maybe I’m just paranoid but isn’t buying a Tesla and using my electric utility (or Superchargers) to charge it trading unknown future gasoline costs for unknown future electricity costs? It’s a great deal now, between incentives and ICE vs Tesla consumption rates but I was hoping to fuel it under my control (and of course, calculate the payoff period once I know costs). I can probably mount 3 or 4 panels to my pergola but another 8 (!) might be a bit of a stretch for ground mount on racks like Will Prowse does in some vids. Ugh… But thanks again!

 

[NJBlue]

A resource, from EcoFlow: https://blog.ecoflow.com/us/how-many-solar-panels-to-charge-tesla/

 

[Skid]

Thanks so much for the advice! The thought occurs that it seems ironic that many solar enthusiasts buy an appliance (a Tesla) that adds significant energy consumption to their electric bill. Maybe I’m just paranoid but isn’t buying a Tesla and using my electric utility (or Superchargers) to charge it trading unknown future gasoline costs for unknown future electricity costs? It’s a great deal now, between incentives and ICE vs Tesla consumption rates but I was hoping to fuel it under my control (and of course, calculate the payoff period once I know costs). I can probably mount 3 or 4 panels to my pergola but another 8 (!) might be a bit of a stretch for ground mount on racks like Will Prowse does in some vids. Ugh… But thanks again!

It’s a significant for storage, but if you’re concerned about generated power it’s about 1/3 of what ICE cars use. It’s far more cost
effective to use the grid to charge an EV.

Consider the rapid gains in efficiency and cost- investing $30000 in a system to keep an EV charged, compared to a few hundred a year on the grid. And the $30000 five years ago which would have bought 1/3 of what it would now buy, and in five years 3 times as much.

 

[OhYou_]

do you not drive the car during the entire day?
what is your vision for a suitable solution?
do you just plan to have like a folding 3 panel solar thing they sell for like camping/RV and use that?
if so you will need ~ 30 of those to charge 25kwh in a day using the whole day.
you will have to go fold out 30 of them every morning and plug them all into some kind of combiner and then into the inverter and into the car.
and that is assuming the car never moves


I've wondered sometimes if vehicle OBC units can handle direct DC input through the normal AC connectors, or if they use relays/coils or a voltage doubler circuit. It would be a costly experiment but that would greatly increase efficiency and lower the cost if you could just pwm the panel voltage down to ~340VDC and smash it into the car
There are some costly portable L3 units you can buy that can surely be modified in a way to accept direct DC but at the cost point it becomes a balancing act assuming they can work on a tesla since they are designed for nissan leafs and some pos mitsubishi thing