Battery testing

Over on the Antique Radio Forum, Eddystone Eddy asked for recommendations for a dry cell battery tester that tests the battery under load.

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My favorite for this is the Simpson Model 379 Battery Tester. I had spotted one at NEARfest a few years back and regretted not picking it up then. I spent some time searching for one on eBay and finally found a nice specimen, although at a steep price.

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But it did come with the original box ...

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... and test leads. 

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I had to rebuild them as the old rubber insulation had hardened and cracked. 

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The web-site has a scan of the manual.

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RCA also made a similar meter, the WV-37.

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(Photo credit: Joseph Rebar on

Jeremy Schotter has a scanned copy of the manual for the WV-37A on his web-site. One interesting feature of the WV-37 is that the range switch has blank positions where you can customize the imposed load and the voltage range.

However, you can also make a quite effective battery tester if you are armed with the battery specifications, a resistance substitution box, and a DMM.

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Just connect the resistance substitution box in parallel with the DMM, set the resistance value to give the current draw that you want to use when testing the battery, ...

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...  measure the battery terminal voltage under load, and compare it to the manufacturers data.

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Here are some more views of the Simpson 379 Battery Meter.

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© Steve Byan 2011-2019