If all you want is a short rule of thumb here is it \u2013 You need 25W of charge power for each LiPo cell, for a 5amp charge rate. One 2s = 50w, one 3s = 75w, two 3s at the same time (or one 6s) needs 150w, and if you want to charge 2 6s at the same time, plan on at least 300w.