From: jmuchow@SPAMMENOTcamlight.com (John Muchow)
Subject: Re: Reducing contact resistance for low volt use?
Date: Wed, 08 Jan 2003 09:56:27 GMT
Organization: MindSpring Enterprises
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X-Server-Date: 8 Jan 2003 09:58:31 GMT
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>>> Then the resistor IS the load, as well as the pick point, or do you
>>>use a load bank somewhere?
Variable MOSFET load, with gate voltage varied based on voltage
measured across a shunt.
>>> They have data logging DVMs now, with software, quite cheap. Fully
>>>capable of deriving every bit as much information from the tests as
>>>your overkill sampler, guaranteed. :-]
There *are* some decent inexpensive data-logging DVMs out there. But
we already have a data logger that we can use.
>>> The need for the resolve just isn't there as the events occur fairly
>>>slowly. Unless you think that you can actually garner information
>>>from failure mode event captures. I doubt it as a picture of the
>>>battery failing yields nothing (the dvm could grab it too anyway).
>>> You are plotting events so long, you could sample once a second, and
>>>get the same data, right up till it avalanches or fails. After ten
>>>percent of that roll-off, it doesn't matter. Especially down at near
>>>zero volts already.
I agree. We're sampling at 0.5Hz until the cell drops to 0.5V
>>> For the wire, the tester... some for the battery too. If the data
>>>logger has multiple ports, you could set up a string, and test in
>>>parallel to see if series batteries discharge evenly. (light bulb in
>>>head). A meter could be placed on
Single-channel logger, unfortunately. Plus, a 2-channel thermometer
with type-K thermocouples,
>>> The qual engineers have labs where batteries get tested to
>>>destruction, you can bet.
Perhaps. They denied that such data exists though. Might be the
truth, might not. The results are the same...we need to test
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