Dry, warm, April or May i believe. Probably around mid to upper 80's. Then i was using distilled water, baking soda. The cell then was stacked washers on rods, 50-2 1/4 inch washers and 156-3/4 inch washers staggered. I wanted the water warm so i had my reservoir next to my exhaust manifold. Funny thing is the reservoir didn't melt, the gen did!