Torturing AA alkaline batteries?

Nubo

Enlightened
Joined
Dec 23, 2004
Messages
461
What's a reasonable limit for current draw from alkaline batteries?

One option I'm trying to design into my light is using 7 alkaline batteries with regulation to power a GH44 bulb at something like 6.6 volts. That bulb's specs are about 1.7a current. I'd imagine at first the batteries would be "seeing" about 1.25 amps demand as the "duty cycle" of the regulator, but then would ramp up to the full 1.7 amps as the light fell out of regulation.

On the ragged edge for alkalines? Or simply too much?

Would a 7-cell pack even be able to deliver these currents? I've seen references to alkalines' "high internal resistance", but don't know the specifics.

I'm trying to design this light to take AA of either NiMH, alkaline, or Lithium.

Does that 2nd option stand a chance?
 
Not sure about Alks, using C or D cells you might manage it though, NiMH should easily be able to handle it. Liths, yes, but that'll get very expensive, very rapidly.

I'd go for the NiMH option if I were you, will probably be easier and cheaper in the long run. Your light will run in regulation longer as well thanks to the flatter discharge curve.
 
That's way too much for alkalines. Runtime will be very limited. You could reasonably spec your light to be intended for use with NiMH but useable with alkalines in a pinch. That's sort of the situation with digital cameras, which might take 100 or so shots on a charge with NiMH, but a dozen or so with alkalines if your NiMH go flat and you have no spares.
 
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