Subject: Re: Reducing contact resistance for low volt use?
Summary: What do you think of these ping times eh?
Reply-To: You can't see me, and I pass right through planets...
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Date: Mon, 06 Jan 2003 12:35:57 GMT
NNTP-Posting-Date: Mon, 06 Jan 2003 07:35:57 EST
On Mon, 06 Jan 2003 06:20:59 GMT, jmuchow@SPAMMENOTcamlight.com (John
Muchow) Gave us:
>1600mAH? Where did that come from? Most of the cells used in these
>high-current applications are 2400-3600mAH. And in 20-30 cell
>strings, they most certainly do deliver a LOT more than 100A.
Not when they are in series, as you described. In order for a
battery bank to scale UP in ampere hour rating, they have to be in
parallel, not series. If series ed, they only exhibit the rating of a
single cell, as what scales UP in a series battery pack is voltage,
not current capacity. This rule does NOT vary. It is basic
>only discussed packs when mentioning these applications. We only want
>to test individual cells though (for several obvious reasons).
They won't need to be tested to the current levels you describe.
You can test overall performance from one maker to another by
logging data at a lower discharge rate.
Full short discharge tests won't tell you which brand is better per
se. Such tests will cause some batteries to fail from any maker. I
doubt that you could gather stats that would yield valid choices.
Your tests should monitor the battery voltage, and you should perform
loading variance to remain above a pre determined voltage. That plot
will show how well the battery will work in real world scenarios.
A motor will not run if the voltage drops to zero. More batteries are
needed, not your "better at working into a short" tests. It's like
asking a car engine to run after dumping the clutch while up against a
wall with the brakes on full.
If your battery packs are seriesed batteries to obtain higher
voltages, then you need to place two or more battery packs in parallel
to gain higher power handling ability. Looking for the brand that
fights into a dead short the best is futile, in my view. You should
concentrate on keeping the pack at voltage. That means more batteries
(battery packs), in parallel.