If possible, I would like a simple illustration showing the recharging of a battery, with polarity symbols indicated (perhaps showing a DPDT switch if batteries are to remain insitu for charging). I seem to recall the dim very distant past that when recharging a lead/acid type battery that polarity was reversed for charging. Maybe someone could affirm this and also show how ni-cads and Nickel metal hydride batteries (cells) are charged. My adult son is showing an interest again in R/C boats and I cannot make sense of this recharging business.