So far my cells have not stopped producing with just the KOH as the anti freeze. I know this will not last. It is 15 f right now and I bet I'm getting slush. My next step is to completely wrap the cells in an insulation blanket. Like a home hot water heater. My cells produce very little heat because of the low supply voltage. I'm researching ways on how to create a 12vdc heater; wire wrapped around the cell and a few current limiting resistors might work. (then wrapped in insulation). I put -32 f washer fluid in the bubblers so they don't freeze, works good.