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...
References: <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <email@example.com>
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Date: Tue, 07 Jan 2003 07:47:02 GMT
NNTP-Posting-Date: Tue, 07 Jan 2003 02:47:02 EST
On Tue, 07 Jan 2003 02:34:34 GMT, jmuchow@SPAMMENOTcamlight.com (John
Muchow) Gave us:
Find the shorter, stub or even button sized cells. Less than half
the weight, same voltage. If time is a factor, and there is little of
it, a smaller parallel array might be better than the bigger seriesed
array. Maintaining voltage guarantees that the current will be up
there. Dead shorted paralleled packs would certainly drop down in
voltage less than the series string. That math is easy.
They start at 24, and IMMEDIATELY upon turn on, drop to a couple
Parallel up two twelve volt packs that end up with the same cell
count, and see that the twelve volt pack does not droop quite as far.
So it comes down to this:
What do you want? Good grammar, or good taste? :-]
> Most builders are within ounces of their weight limitations for
Sounds like some paring is in order in other areas. :-]
>And R/C plane and car builders certainly can't add
>another string of cells.
I've seen some pretty lanky craft get up in the air.
Hey! I know! Make it like a train! Use a single piston gas motor
to turn a high output DC generator that not only keeps the batteries
peaked up, but assists on the current needs of the motors!
Haha! A solution! It weighs less that one additional battery pack
would, and gives more!
>Especially when the guy next to them is only
>running one string at very high current levels (way beyond "spec")
>because the cells will last the short time he needs them to.
That's why I mentioned smaller cells to reduce weight so that cell
count can go up. The problem is, two small cells are no better than
one larger one, EXCEPT for distribution of the currents. Instead on
needing 100A contacts, you would only need 50s, meaning that losses
related to weak or not completely integral contacts would be reduced
by one half, despite the cell count doubling. Each contact would have
to do less work.
What the makers need to do is offer a battery that has threaded
tophats for end caps that are well connected inside the battery.
Then, YOUR connections could be made much tighter, and would warm and
drop much less.
There YA GO! Make a "C" clamp device with the contactors on the
jaws of it. Clamp up some dead batteries from each brand to determine
the pressure at which the contact begins to crush (battery shortens).
These documented pressures could be used from a chart so that the
tester operator would know how to keep from over tightening the clamp,
thus assuring the tightest, least destructive grip. Then, sharp
contact pins that have had their heads shaved a bit more flat, instead
of points would be what you put in the jaws. The LOAD BAR, or
whatever you guys call it would be directly attached to those pins,
and the metering leads as well.
There are single arm hold down clamps that clamp downward toward a
flat base, similar to those used by glaziers in the glass industry.
One could position the battery in a slightly or fully sunken well
milled into a block of delrin or teflon or G10 or even aluminum (Hey,
no more vault needed!). The bottom contact could be the aluminum
block. The top contact would be positioned on the underside of the
clamping device. At high clamping pressures, the worst that would
happen at very high surge values would be a welding of the wire or
contact to the battery. Parallel up clamps on a plank for a
pre-assembly array tester.
Instead of the jaws of life, it could be the "Jaws of Juice".