On Wed, 31 Oct 2018 at 08:05, David Van Horn <
david.vanhorn@backcountryaccess.com> wrote:

> Some NIMH will "Tolerate" low current overcharge.  This requires more
> catalyst to recombine the hydrogen and oxygen, and these cells usually
> aren't the highest capacity.  Most NIMH cells specify ZERO float current.
>
> Nicad is better in this regard, as well as working over a wider
> temperature range.
>
> NimH can (could) be trickled at up to about 1600 mAh in AA size. Above
that the recombination material is removed and by about 2000 mAh the
ability to trickle is usually ~~~=3D zero.

NimH can be clamped at 1.45V usually and 1.4V is safer at <=3D C/10 charge
rate and be "safe enough" in not too extreme temperatures in most cases
[tm].
(ie the clamp absorbs the current when 1.45V is reached.
Higher charge rates increase the likelihood that the cell will run through
the voltage limit and accept charge indefinitely.
I specify that voltage based on my tests some years ago with as many brands
of rechargeable NimH AA cells as I could obtain and tests from 'room
temperature' to about 50 C.
Capacity is < 100% possible but good enough to be worth the simplicity.


      Russell
--=20
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