Solar panels to EV charging

That's because of the difference in power levels. A good solar panel is about 1 meter x 2 meters and makes 400 watts on a great day, angled right at the sun.

An EV might use 10-20kw to cruise on the highway?
So, you'd need 2-3 semi trailers covered in panels to cover driving on the freeway.
Alternatively, a single 400 watt panel would need 25+ sun hours to get an hour of freeway driving.

In short, the math just isn't there.

I've got 20 - 325 watt panels on my house and a set up to limit charging to use just extra output from the panels, even those 20 panels is just enough to do school drop off and pick up plus a quick in town errand.

It's DC from the solar to 240vac, then the car converts to DC with it's onboard charger.

A DC charger compatible with CCS1 is in the $50,000 range. And that's coming from 480 3-phase. I can't imagine what it would cost coming from the variability of PV DC. With how low the production/demand would be, that feels like an unobtainable product.

I'll take the efficiency hit and use my $400 EVSE.

6 amps is the min charge current for J1772

Also, I assumed this was a factory produced EV with a standard charge port.
But, the OP has discussed building conversions and now I see the 144v note about his car.

If we're talking about a low voltage EV conversion, I'm all for direct charging if you can find a 144v MPPT and build a safe charge port.

If the vehicle has only a J1772 /CCS1 combo port. The only feasible option is using an AC EVSE.

cricketo said:

6A at 240VAC is roughly 1400W

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The spec also allows 6a at 120vac
It doesn't change your point, I just wanted to clarify

remy_martian said:

One thing you are casually ignoring.

The solar system you propose, with a 144VDC car as an integral part of it will fail county electrical inspection..."high voltage" is anything over 48V, iirc.

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Safety be damned. JK
Also, I believe code was written for 48v nominal. From memory, that puts the cut off at 60v.


Overall, I think it's a moot point.

This imaginary PV would do the owner the most good if it also provided power for the house/anything other than the car.
As proposed (PV - some black box - car) the solar would be unused when the car battery was full or being used.
So, doing a normal 48v battery (for the home), MPPT charge controller, and 120/240 inverter. Then charging the car as needed from AC. Yes, it's less efficient. But the parts exist and can be installed safely/to code.

Electric Land Cruiser said:

The software already exists to switch between charging the EV and charging batteries and throttle output to match what solar is generating.

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Can you provide examples or links to this software?

I've never seen a Enphase, Victron, SEIMENS EVSE/car charger.

Electric Land Cruiser said:

Right, you use any old EVSE but limit the power it has available.

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?

That's not how an EVSE works. You can't limit the available power. If you only "allow" it with 500 watts the car/EVSE is still going to take whatever it's going to do. Or if there really is only 500 watts available, something is going to fail or fault out.

remy_martian said:

The EVSE limits the current to the car. My Bolt EV is limited to 12 amps. My Flo is limited to 32 Amps. My Tesla wall "charger" is limited as well. If the car asks for more current, the EVSE sends this to the car: 🖕 and negotiates the max the EVSE is set to allow.

Tesla got clever and incorporated identification in its plugs and varies that limitation.

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I understand how the EVSE sets current limits using the pilot signal. Not exactly the car asking for more and the EVSE involving birds. It's just the onboard charger respecting the current limit set by the EVSE.

Most EVSE's can't actively adjust charge current to match available solar power. It's just on or off. And even the on/off is normally just a set timer based solely on the clock.

The issue I'm getting to is the adjustment to match available PV or turn off when there isn't enough.