Hi Brian. I purchased an "omni" NiCd/NiMh charger wot caters for 2-10 cells off the jolly old..dare I mention it., E-bay jobbie.. It seems to work ok,  If in doubt buy something from a specialist battery supplier. The price varies quite a bit in my experience of surfing for the bargain, I would be doubtful of extremely cheap chargers tho`(on general principle). This one is switchable for various voltages and is automatic (so it switches to trickle charge when it senses the batts are full) so it will do my main and transmitter batts. NiMh cells do not have "memory" so do not need discharging fully. It is my understanding that they take a few full charges before they attain thier ultimate capacity. My personal preference is not to fast charge batteries. i am new to nimmies as well, my experience is mostly gel lead-acids, as my boats up to now have been capacious enough for them..   Ashley