"Edwin Pawlowski" wrote in message
m...


wrote in message ...
Just had to replace the batteries in a pair of Vtech phones (model
20-2481).
Old were nicad. New are Nimh. Differences? Best way to charge, how
often?


NiCad can develop memory, should be deep discharged at time before
charging.

Nimh can be topped of without any memory effects. Lat longer, generally
more cycles. Often more power in the same sized cell.


Nimh are preferred for applications such as cell phones because they have
higher capacity. However, the NiCad have higher current capability and are
preferred for applications such as portable tools.

NICad memory has been proved to be somewhat a myth. It exists only under
very controlled conditions such as repeately discharging to a specific state
of charge. And, it the situation is reversible by one heavy discharge and
charge cycle. It is best to not discharge any battery any more than
necessary. Normal use will result in discharge to different levels of
charge. Many experts will tell you regardless of what the manufacturer says
avoid total discharge. I agree. personal experience using NiCad batteries
in an application where they lasted for more than 30 years with proper care,
never being allowed to discharge below 40% state of charge and never over
charged (that's the tough part to do for most users).

For extensive detail do a Google search for "NiCad Memory" Myth



A good one:
http://vancouver-webpages.com/pub/peter/nicad.faq