Found a site with lots of FAQ answers on NiCad and NiMH chargers and batteries.
http://www.greenbatteries.com/bachfa.html
* What's the difference between a rapid charger and a fast charger?
* Does rapid charging reduce the life of batteries?
* How long will it take a charger to charge batteries?
* Can a battery charger damage a battery (shorten its life or reduce its capacity)?
* What is trickle charge?
* Is trickle charging harmful?
* What's the difference between a NiMH battery charger and a NiCd battery charger?
* Can I use an older NiCd battery charger to charge NiMH batteries?
* Which are better, NiCD or NiMH batteries?
* What is battery conditioning or exercising?
* What is a charge channel or charge circuit?
* What is a charge station?
* What makes a charger a "smart charger"?