Re: 1502 TDR project

Tom Gardner

NiCd cells have a longer shelf life than lithium cells - I believe.

The 1502/3 has a nasty characteristic - even when turned off there is
a current drain of ~1mA through the chart recorder. If left
discharging then eventually the weakest cell will discharge first and
then be reverse charged - and that's bad news, It is behind the
statement that the battery should be fully charged once a month,

My solution is simply to remove the battery pack when not in use. Even
if each cell self-discharges, it won't be reverse charged.

But you should treat that with caution; I'm not a battery expert.

On 10/12/2019, Mark Pilant <> wrote:
> tabbed C NiCd cells are easily available, so the battery can be

Very true.

However, my own problem with NiCd batteries is I use the equipment so
I would be constantly replacing batteries. I understand this is less of an
with NiMH and Lithium batteries, but then you can get into making changes to
charging circuitry to get the correct charge rates.

I may try the bench power supply just to see if it turns up additional

- Mark N1VQW

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