From: Roger Johansson
Subject: Re: Reducing contact resistance for low volt use?
Date: Fri, 13 Dec 2002 12:16:58 +0100
References: <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org> <email@example.com>
NNTP-Posting-Host: dialin-sto-hc-37-213.direct2internet.com (18.104.22.168)
X-Newsreader: Forte Agent 1.92/32.572
Roger Johansson wrote:
>Or one big mosfet, in parallell with the u-shaped copper bar, which is
>adjusted during the test to give constant current.
>Now we have a constant current test again, but we have solved the
>problem with getting low enough resistance, and the mosfet only needs
>to take a small part of the load.
The test equipment could be in two parts, one mechanical unit, the
copper bar and mechanical level to press it against the battery, the
other part amplifier, mosfet and logging circuit.
One part of the copper bar is used as a shunt, The voltage is
amplified and used to steer the mosfet to keep the current constant by
shunting the rest of the copper bar.
So the u-shaped copper bar needs 3 terminals, at each end and
somewhere in the middle.
Different copper bar for different currents, like one for 30A another
Machine the copper bar ends to fit tight over the battery terminals.