I have done some research on that, but I found that the amount of solar panels I would need to power my grow would cost around 20k. You can use solar as supplemental energy, but that gets a tad complicated with the batteries and the wiring scheme of the whole thing. for a 400w light only running while the sun is out so around 12 hours a day, would cost about 3k. And this one runs at 16 volts, so you would probably need a power inverter.
Amazon.com: Sunsei 71015 SE-24000 400-Watt 16.5-Volt Solar Panel Generator: Home Improvement
Good luck,
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