There are also cycle chargers. These cycle chargers, and I am pretty sure Da Rock's AccuCycle and am sure that the Triton, are both cycle chargers. What this does for you is to allow you to discharge a battery then recharge it. This does a few things for you. First, with NiCd's, it will remove any tendency to have 'charge memory' which can hurt a battery. This is the tendency for a battery to not fully charge after a number of limited discharges. Cycling the battery fully discharges it, then recharges it. Repeated cycle, say three or four times during a period of a couple of days, will remove this memory tendency and usually restore the battery to almost, if not all, it's original capacity.

The other point that Da Rock brought up is a good one. That is that with some of these chargers, you get the digital indication of just how much current was put back in the battery after the recharge is complete, even if you do not cycle it. This will give you some knowledge about just how much of that valuable current you used during a flying session (or flying afternoon session.. whatever). And, with some chargers, the Sirius for instance, will give you an indication of a problem that may exist in a battery pack.

I have the AccuCycle (not the elite, but an older one), a Triton, an ICE, and two Sirius chargers as well as the Sirius discharger (with digital readout). The Triton, Ice, and Sirius are all powered by 12 volts DC and are considered field chargers, where the AccuCycle (my version anyway) is a bench top type charger that requires it to be plugged into the household AC source.