From: jmuchow@SPAMMENOTcamlight.com (John Muchow)
Subject: Re: Reducing contact resistance for low volt use?
Date: Tue, 07 Jan 2003 02:07:59 GMT
Organization: MindSpring Enterprises
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X-Server-Date: 7 Jan 2003 02:09:49 GMT
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>>> Hahahah... #2 wire on a "D" cell. How hilarious. Your devices stall
>>>from the raw weight you put on them.
The weight of #2 wire is inconsequential in a 250lb, 9HP robot.
Several builders use even larger gauges to their battery packs (20-30
cell strings of C cells, typically) and almost all of those
connections are soldered.
>>> Again, testing banks is one thing. Single cells, entirely another.
>>>Testing them to the point where their voltage drops to nil due to
>>>short circuit loading as opposed to "normal" discharge rates...
>>>Not needed. If your discharge rates are of such a nature, you are
>>>stepping outside the specs for the battery's proper use.
Yes! You finally get it!
There is NOTHING in a combat robot that is used at the component's
spec. In fact, a builder who does so has almost no chance of winning
an event and will challenged by other builders to explain why they are
wasting their time building such a machine. We don't need thousands
of hours of life. If the motors, batteries, wires, etc., last a few
hours, we're happy. If they last 3 minutes during a fight, we're even
100A discharge current, though at the high end of the scale, is not
unheard of. Plotting voltages and time-to-discharge curves for
discharge currents from 5A to 100A is a great way to see if there are
any differences between manufacturer's cells (and at waht current
levels they occur). If not, GREAT, we can purchase the least
expensive ones. If there is, we need to know.
>>> Denying that, and moving forward with the improper usage doesn't
I would *never* use a component in my 'bot at its rating (except for
radio receiver max Vcc). That's "proper usage" in a combat robot.
Improper usage is sticking to the ratings. It's a waste of time and
money as all the competition will have faster, more powerful, and more
dangerous 'bots to stomp mine with as I limp around the arena.
>>> Like I said, you need MORE batteries in parallel, not series.
No, I don't.
If we can run our batteries at high discharge current levels (without
having to parallel additional strings of cells together), then I have
more weight for armor, weapons, etc.
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