Didn't think what ? That I explained the end-to-end solution ? I didn't, because that wasn't the question, and my name ain't BrianDidn't think so
Solar panels to EV charging
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You didn't. You said it would be complicated with no easy path, "but theoretically possible."Didn't think what ? That I explained the end-to-end solution ? I didn't, because that wasn't the question, and my name ain't Brian
So you described a theoretical possibility. No solution. I offered a solution that actually works
If you want to be pedantic, you haven't offered anything. You basically described how people do charge EVs while being off-grid and solar-powered. You murkied the water by bringing the topic of micro-inverters, which are irrelevant. If you're charging from AC, you're charging from AC. Whether AC is a product of solar, wind, hydro or diesel is not important.You didn't. You said it would be complicated with no easy path, "but theoretically possible."
So you described a theoretical possibility. No solution. I offered a solution that actually works
Now if the question is how to charge a factory street-legal EV from PVs directly via DC, we can talk about that. That wasn't the original question (factory street-legal EV part) though based on the voltage and chemistry the OP mentioned. So assuming that is your question, the answer is the following...
First we would require a charge controller that can operate in the desired output voltage range. Charge controller will also dictate the open circuit voltage of the PV array to achieve such output. Say for a 96s configuration we'd need to be putting out 403.2v or so, charge controller needs to be able to output that, and will likely require something like 500VDC OCV on the PV side. Then we need to hook up the output to the high voltage path of the EV. That's the same place where on-board charger is connected, and the same place where CCS or ChaDemo DC paths would terminate if present. For a moment we assume that EV doesn't have those. Finally we need to activate the DC path by telling the BMS that we're charging. That would probably involve some kind of CAN messaging specific to the particular vehicle.
Now if the vehicle is in fact equipped with a CCS or CHAdeMO adapter, then we can also exploit that. Would need to implement the wiring and the negotiation protocol - there are already projects showing that, especially CHAdeMO.
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Then what happens the next day when it's overcast and the panels aren't putting out 500 volts anymore? No charging that day?
Correct. Output will be fluctuating from max to none both with the time and also with cloud cover. It may be impractical in some cases, but that's again not the question.
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Sounds like a bad system if you can only charge in perfect conditions. I like mine better.
You should use whatever works best for you. But you also should remember even a system with an additional battery to balance out the supply-demand is not bullet proof if your system is under-producing. So for example, I have a 6kW solar array (actual system I have, not a hypothetical one). On a cloudy winter day (basically 5 months out of the year in PNW) it will put out 100-200W of output. That is way below the threshold to drive even the Level1 charger, which needs something like 1.2kW from AC. So effectively one would need to charge up the stationary battery for a few days in order to charge the EV for a few hours. With DC coupling those 100-200W could trickle into the EV's battery without much trouble though, and without additional losses which will amount to decent 25% or so in your system.
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Smart microinverters to the rescue! Using production and consumption monitoring you can throttle the output to the EVSE to match what solar is producing and no more.
You're side-tracking again, but I am curious nonetheless - what's the minimum charging current for J1772 ?
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.
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.
6A at 240VAC is roughly 1400W. So if the array is putting out a couple of hundred watts, no matter how smart your inverters are, you can't satisfy that demand. So you end up shedding the load, charging your stationary bank until it reaches minimum capacity, then firing back the inverter output to begin charging. Besides inefficiency in multiple conversions this obviously adds charge/discharge cycles to the stationary battery.
Bottom line - ELC was arguing that such approach is "better", and I can only agree that it's probably better in a sense that it's more straightforward for an average Joe to implement. Otherwise it requires more components, operates at lower efficiency. One example where "my approach" is better, and is basically the only game in town, is camping. I hope I don't need to elaborate what I mean...
Bottom line - ELC was arguing that such approach is "better", and I can only agree that it's probably better in a sense that it's more straightforward for an average Joe to implement. Otherwise it requires more components, operates at lower efficiency. One example where "my approach" is better, and is basically the only game in town, is camping. I hope I don't need to elaborate what I mean...
The spec also allows 6a at 120vac
It doesn't change your point, I just wanted to clarify
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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.
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.
That didn't make any sense to me, can you elaborate ? What exactly would be against the electrical code, assuming one had a desire to be up to code and get an inspection ?
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.
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Yes, exactly. When the solar panels aren't generating enough power to meaningfully charge the car, then they charge the battery bank storing the energy for future use. And as stated the lowest charge power for the J1772 is 1440 watts at 240VAC but at 120VAC then it's 720 watts. Easy to hit those numbers nearly every day with a 2-3kw array. Versus your idea which can only charge on perfect weather days and gets knocked out by a single passing cloud. Your idea is not more efficient; the panels produce power every single day, some days more than others. The point of solar is to capture that energy and use it.
The features I'm talking about are all native to the components and the price of microinverters vs. an MPPT large enough is at best a wash but most likely the microinverters will be cheaper. The software already exists to switch between charging the EV and charging batteries and throttle output to match what solar is generating.
In the end you agree that mine is better begrudgingly. Your system still doesn't work for camping because now you need to have your absolutely massive array become mobile and oh yeah it still needs a perfect weather day to work.
Can you provide examples or links to this software?
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Enphase, Victron, SEIMENS, pick your poison. Configurable to your heart's content.
Holy cow, after all of this back and forth you're still "confused." I rest my case.
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