Actually, during the night and on cloudy days the energy is supplied by my traditional provider instead of solar cells and the surplus is sold to the supplier
Some parts of this country have a "night tariff" which is much cheaper than the daytime rate. Was thinking that this combined with a battery array could be a cost efficient way to run a rig by only ever buying "night tariff" energy. Not something I have explored in great depth though I'm sorry to say.
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