Hi Alan,

Here is a link with some info:

http://www.videofoundry.co.nz/ianman/laboratory/research/battery.shtml

You might also look up Peukert Effect, although that is mainly
relating to lead-acid batteries.

A good Alkaline AA cell has a short-circuit current of about 20 amps.
For a 9V, it's only about 6.5 amps. NiMH will be slightly higher. 3A
isn't bad at all for a AA for short bursts. It would also be possible
to do this capacitively, but you would need a fair amount of
capacitance, depending on how much voltage sag you can tolerate during
the pulse. 300000 uF (0.3 Farad) would give you about 0.1 volt sag
during your 10msec, 3A pulse. Probably the best combination would be
some capacitors and the AAs.

I would avoid the 9V batteries. They are a bunch of really small cells
connected together.

Sean


On Mon, Aug 17, 2009 at 11:20 AM, alan smith<micro_eng2@yahoo.com> wrote:
> I have an application where I need to burst out up to 3A at 7Vish for 10m=
Sec, so either using some AA in series, or a 9V. =A0The question I am tryin=
g to determine is how much burst current I can get out of a battery before =
it gives up. =A0I was also thinking perhaps using some sort of capative dis=
harge circuit. =A0The burst itself will be gated using a FET.
>
> Has anyone done any research on this?
>
>
>
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