To be honest, I don't really trust voltmeters to tell me how my batteries are. I care about capacity and a voltmeter won't tell you that. That's why I cycle the batteries. I charge them, let them sit overnight and then cycle them. So far they have stayed above the rated capacity.

Also, if you care to do it, you can hook up plugs to fit any of your nicads (cell phone, cordless phone, Dremel Mini Mite, etc.) The Sirius will keep them all in good condition.

The chargers that come with those items trickle charge them to death. It's kind of a pain hooking up the extra connectors, but it's worth it for some things.