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NiCd Battery Care and Storage

The Care and Feeding of NiCd Batteries
I have in front of me a NASA publication on the care and feeding of NiCd batteries, as learned from 30 years in space satellite operations. What follows here are some excerpts from this text organized in some potentially useful manner.

This is not an exhaustive dissertation and comes entirely from the experiences of NASA scientists and engineers and what they have decided are the important points to discuss in their publication. This doesn't even touch on all of what they did, its only the parts that I thought would be interesting to those of us in the RC hobbies. For more information see my reference to the publication at the end of this page.

I am not an expert in NiCd batteries and I am stating right now that I am not even trying to pretend that I am one. I am just regurgitating information that I have found in a NASA publication on the care and storage of NiCd batteries.

A common term you will see in this C something. Just substitute your packs' rating for the C, for instance: C/100 for a 1700 pack would be 1.7ma or C2 would be 3.4Amps (3400ma).

Storage of NiCd Batteries
Guideline No. 2 Flight batteries should be maintained in a discharged and shorted condition and stored at cold temperatures when not required for "critical" spacecraft testing. Optimal temperature is around 0 degrees C. NASA does it this way:

Discharge at C/2 constant current rate to first cell at 1.0 Volts
Drain each cell with a 1 ohm resistor to less than 0.03V
Short each cell with a bar
Place batteries in a sealed bag with dessicant (stops condensation)
Store in cold temperature (about 0 deg C)
To re-charge such a stored battery Guideline No. 7 A battery stored discharged and shorted for a period greater than 14 days should be activated with a "conditioning cycle" prior to placing it in use. The conditioning cycle (20 deg C) is defined as follows:

Remove from cold and allow to come to room temperature
Charge at C/20 for 40 hours +/- 4 hours (Deliberate over-charge)
C/2 discharge until first cell reaches 1.0V
Drain each cell with a 1 ohm resistor to less than 0.03V
Short each cell with a bar for 4 hours
C/10 charge for 16 hours +/- 1 hour
Do steps 3 and 4 again
C/10 charge for 16 hours again ***
*** Steps 4,5,7 and 8 are not needed if the batteries haven't been stored for an extended period of time. See note in Guideline 9 below.