Well, as you've probably already realized, there is more to charging batteries than "Plug it in and crank the charger to max." The setting is there on the charger for a reason. Charge too fast, and you can damage the battery.

This is where the concept of "C" comes in. C is a term used to define the one-hour charge rate of a battery, and is equal to the battery's capacity. For example, if a battery is rated at 600mAh, then C is 600mA.

If you charge the battery at C, it will take approximately one hour to charge. If you charge a battery at 2C, or twice it's capacity, it will take about 30 minutes. 3C, about 20 minutes. 4C, about 15 minutes, and so on.

Now, depending on the size and type of battery, you have to be careful how fast you charge it. Car packs with large SubC cells can be charged as fast as the charger will charge. Smaller electric flight packs, especially NiMH ones, need to be charged at a lower rate to avoid damaging the cells. In general, you can charge NiCd cells at 2C, and NiMH cells at C.

2.0 (Amps) is not a trickle charge. 50mA is a trickle charge. You should be charging your 830mAh NiMH pack at no more than .8-.9 Amps, and your 600mAh NiCd packs at no more than 1.2 Amps.