Nicad and nimh charging specifics?

[Daniel Morrow]

Hi I thought I would try a new subject. Could someone tell me standard
charging specifics for nicad or nimh batteries, trickle and/or
otherwise? Also, is it possible to overcharge these batteries by
trickle charging them? Thanks.

 

[happyhobit]

Hi Daniel,


Trickle Charging

Constant current charge at 1/10 C for 12 to 14 hours. C = capacity of
battery. For a 1500 mah battery you would charge at 150 ma for 12 to 14
hours.

Yes you can over charge a battery at a trickle rate. After the battery
reaches Full Charge the excess current will start cooking the battery. If
the battery is getting hot, it's cooking.


Peak Charging

NiCad
Constant Current charge at 1C until the charge voltage drops by 15 mv per
cell.

MiMh
Constant Current charge at 1C until the charge voltage drops by 5 mv per
cell.

Some Peak Chargers monitor the battery heat for the reasons noted above.


I suppose you could build a charger based on battery temperature rise.


Jay

 

[Daniel Morrow]

Thanks happyhobit and Steve.