On Tue, 15 Aug 2017 09:29:23 -0400, Dennis Lee Bieber wrote:

> Lead acid typically works with cheaper charging circuits, and work well
> with a continuous float charge -- unlike NiCad/NiMH/Lithium rechargeable
> with their multistage charging cycles and warnings to remove them from
> the charger when they are "full"..
>
NiCd worked perfectly for this sort of usage. You just had to keep the
charge rate down. At a 1% rate or thereabouts NiCd batteries could be
left on charge for years at a time: perfect for UPS-type operations.

I used to use 50mAh cells made up to 4 or 5 cell batteries them to run
timers on models. The batteries were permanently on in the model (the
timer drew 300uA except when it tripped its solenoid (500mA for 15mS) and
when at home the charger was always on and plugged into the models. It
was  continuous current design set at 900uA: take off the 300uA the timer
used and the remainder is near as dammit a 1% charge rate.

AFAIK NiCd is the only chemistry that will work this way, so its sorely
missed here.

NiMH has a rather too high self-discharge rate for this charge regime to
work well with it.


--
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |

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