[FARC] ni-cad cells
Rolan O. Clark
rolan.clark at comcast.net
Thu Mar 4 07:17:15 EST 2010
All,
I have 50 plus 10Ah Ni-Cad cells that anyone can have. They still have the shorting wire across the terminals and the recommend way to restore them is to charge at 1/100 the normal AH rate until initial charge is reached. Each cell is about 4 x 6 x 1 inches. Each cell should be in clamp to keep them from expanding while charging.
The initial charge rate would be .1 amps till charged.
Then the normal charge is Ah/10 rate, or in this case 1 amp, till they reach the full charge V and like all Ni-cads it is recommend that they be close to fully discharged before recharging so they don't exhibit the 'memory' problem.
I will take them to the special collection by the county on May 22, I think it is, if no one wants them.
They may be 20 Ah cells but I think to be safe treat them as 10 Ah cells until they have charged and you can discharge them to see what their capacity is. One rule of the thumb for Ni-Cads is the Ah capacity should be .75 Ah rating for .75 hr so, if a fully charged cell will go from full charge to 1.1 V with a 7.5A load for 45 minutes then it is at least 10 AH.
You could discharge a fully charged cell at 15A (20Ah X .75 = 15A) and see how long it takes to reach discharge, probably 1.1 would be discharged, and if the charges lasts 45 minutes then it is a 20Ah cell.
Take care,
73 de rolan w3fdk
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