Rodney said:
Hi,
If you connect four 1.2 volt NiCd or NiMH batteries in series(end to
end) you will have 4.8 volts which will probably work. If the rating per
battery is 600mA hr( you can get better ones) it will theoretically run for
one hour with 600mA drain or a bit less with 800 mA drain. To get 10 hours
of runtime at 800 mA you will need a battery that will output 800 mA for 10
Hrs. That works out to 8000 mA. For that you will need an 8 amp hour
battery. You will have a problem finding such a thing in a small package.
Maybe someone else has a suggestion.
Rod
It's tough to get 800ma for one hour out of a 800mAH battery. They're
rated for longer discharge times where they are more efficient.
I'd double your numbers to allow for some degradation over time.
Fully charged batteries can be 6.4V, although I've seen more.
Fully discharged will be closer to 4.0.
I think I'd do some regulation.
Another issue is that the average power drain of the device may be a LOT
lower than the marketing/regulatory number written on the supply.
You have to measure it.
If it's really drawing that much current, you should look into
alternative solutions to your problem...or get a wheeled cart to lug
the batteries around.
mike
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