Here's a link that shows you how to make and use an ammeter shunt. http://www.motorcycleproject.com/motorcycle/text/shunt.html It should be good for maybe as much as 200 amps for measurements a few seconds long -- if the clips make excellent contact on each end. Because it's made of copper this shunt is highly temperature-dependent -- for every 10C/18F rise from room temperature the reading will rise by ~4%. But it's cheap and easy and will certainly give you a good ball-park reading. For accuracy I would also add a small wire sticking out of the back end of each clip to attach the meter to. It's the length between attachment points that matters. To slow the temperature rise for high currents you could make it serpentine and clamp it between a couple hefty chunks of aluminum. To read lower currents you can double the length between measuring points, so that you get two mv per amp instead of one. Yours, David |
Please note - During the past 17 years of operation, several gigabytes of
Vanagon mail messages have been archived. Searching the entire collection
will take up to five minutes to complete. Please be patient!
Return to the archives @ gerry.vanagon.com
The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.
Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.