Substituting Nimh for NiCD

All:

I have an old ICOM handheld radio with a battery pack that holds six AA cells. There is a switch in the pack between Alkaline and NiCd cells. I assume that the radio holds the pack at a float voltage when the radio is running on mains power, and the pack switch controls the target voltage.

I would like to switch to Nimh chemistry, but I am concerned that the charge voltage levels would be inappropriate. Does anyone know if a Nimh pack can safely be held at NiCd float levels?

Mark

With AA cells.. short answer = Yes. go ahead.

With a large higher voltage ebike pack of nicad/nimh it's a bit more complicated, you can use a Nimh charger on a Nicad pack, but i would not use a Nicad charger on nimh cells because of the end-of-charge detection, nimh is a bit more sensitive and should be done with a temp probe thingamabob....

but for AA cells, and only 6 of them, it will be perfectly fine. I recommend Eneloop cells if you can find them.

I agree you can sub in NiMh for NiCD in this application. I wanted to add that I have had great luck with the new low self discharge cells from HobbyKing. Great price and great capacity.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10456

I run have been running low self-discharge NiMH cells in my Icom R10. And my Tek THS730A oscilloscope. And my Valhalla igniter testers. And a bunch 'o other stuff. Works great. If your stuff ran off of NiCads and had a slow charge rate (say 10 hours) you should be just fine. The NiMH cells have at least twice the capacity so would charge at less than a C/20 rate. NiMH cells can handle this for extended periods without problems. Does take 20+ hours to fully charge.

Thank you all for your quick responses. I was a little gunshy because the pack switch got set to "alkaline" once and blew up the NiCd's.

Mark

The alkaline setting should turn off the charging feature, as alkalines are not meant to be recharged... ( yes, some alkalines can be recharged, but not as a rule.. )