On Tuesday, 26 September 2017 19:22:21 UTC+1, N_Cook wrote:

Silly wind-up torch but could be anything using Ni-Cad or ni-Mh
multi-cells. LEDs are full bright for a short time after winding up ,
then drops to low light level, regardless of amount of winding beforehand.
One cell is out of kilter with the rest, and in use discharges quickly
compared to the others.
Bench ps charging that one , in isolation, cures the problem.
But presumably it may return , unbalanced charge/discharge across the
cells.

likely discharge in the cell from a dendrite. If so the cell's at end of life.

How to do the isolated charging of one cell properly, the next
time in the way of monitoring voltages and charge currents ?

The easiest way is just overcharge them, but it must be done at slow charge, ie 16hr charge rate.

The practical answer is new cells. They're very cheap.


NT