Even if you buy the dedicated charger, which I think is a good idea, consider getting one of these since they work well to recondition the finicky Ni-Cad batteries. I don't think you need the plus II, even the regular maha mh-c777 will do.
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There are a couple on the auction site right now. I have one and will probably keep it forever. They work on all different kinds of batteries, great for keeping ni-cds working well. The spikes can be adjusted to contact the metal on batteries and the little tabby thing is a magnet that senses the battery heat while charging. the charger can be set to discharge and then charge the battery. Bob.