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