Is that 6v 12AH ? If so it should last about the same as five or six sets of
reasonable NiMh AAs. Why not get a nice 400AH battery & charge it up once a
year :-)
Not quite that simple. You get more benefit than the simple math
predicts, since batteries are more efficient at lower [dis]charge rates.
As a caution Lead Acid batteries tend to be ideal/designed for high discharge
rates whilst essentially remaining fully charged all the time (think of car
batteries here). When used for what I imagine will be your long very slow
discharge rate usage they can tend to develope a memory effect that makes
them both harder to charge properly, and also their ability to supply large
currents diminishes.
Not really... they may be designed to *tolerate* high current
levels, and that may diminish their deep-cycle capacity a bit, but they
are still the same battery chemistry. Lead acid batteries (nor NiMH, nor
NiCd except in extremely specially-constructed circumstances) do NOT have
a "memory effect." The death of a lead acid battery is from leaving it
discharged for any length of time.
One of those digital battery conditioner thingies that
pulse charges and continually maintains battery condition might be ideal for
a permanent bench setup - there again it will probably cost more than a small
battery :-)
Those pulse chargers have been shown to be little more than snake
oil.
The deeper you discharge the battery the shorter will be it's
life, ideally you would charge it up when it reaches 80% charge but this
would mean charging it almost as often as you would a set of AAs.
If you look at life cycles of lead-acid batts from a
manufacturer's datasheet, you'll see that's not the case. The total
*energy* moved in and out of the battery is fairly constant... discharge
25% and it will last 2x as many cycles as a 50% discharge. Roughly same
net energy. Leave it totally discharged for a few days and you'll have
lost the majority of the capacity.
If you've left the camera on with the LCD going, it draws about
1/4 amp from what I measured on my -DS awhile back. That's about C/50, so
the battery should last about two days.
-Cory
--
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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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