Graham. wrote:
"Bob wrote in message ...
I have just purchased a commercial device from the far east which is powered by two CR2032 lithium coin cells connected in
parallel.

I can see no positive reason for this at all and some negative ones

The operating current is 60uA and 16uA on standby which it reverts to after 5mins in activity.
I have sometimes seen these cells paralleled up to meet a peak current requirement but there is nothing like that sort of current
being drawn by a couple of chips and a LCD display

Each cell is rated at 230mAh which should give around 3800 hours normal operation and 14000 in standby so well over a year with
mixed duty cycle.

SO why on earth are there two cells fitted??


Any clues?

Bob

PS it is a digital readout scale - a bit like the cheapo verniers but a lot longer.

Does it have any settings or calibration data stored in volatile memory?

Perhaps the idea is you replace the cells one at a time before either
is exhausted.


Good call!
That would enable the current position to be retained but if that were
the design idea, they have not bothered to mention it in the instructions.
The only indication of low battery is a flashing display and as the
cells are hardwired together, they would be no indication of which had
failed. Indeed connecting them that way means their terminal voltages
are identical and so possibly have similar remaining charge in each.

Bob