Small Battery Tester - 9V, AA, etc.

Status
Not open for further replies.

dishdude

$100 Site Donor 2023
Joined
Nov 14, 2008
Messages
16,392
Location
Phoenix
I ran into an issue using my DVM to test batteries. I had a 9V putting out over 9V, but when a load was placed on it, it fell flat on it's face and couldn't power the device it was in. I had another 9V putting out 8V and it worked just fine. This is making me question the AA batteries I was testing that were doing the same thing.

Will something like this load test the battery and be more accurate? Just looking for 9V, AA and AAA.

https://www.homedepot.com/p/Commercial-Electric-Electric-Battery-Tester-MS602H/202353291

commercial-electric-specialty-meters-ms602h-64_1000.jpg
 
I made my own by soldering a suitable load resistor across a battery connector so that a small load was applied when the battery was inserted. The voltage could then be read off with a normal digital meter. Cost nothing as I already had the parts.
 
I like this one:

https://www.homedepot.com/p/Gardner-Bender-D-C-AAA-AA-9-Volt-Battery-Tester-GBT-3502/202867877?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-BASE-PLA-D27E-Electrical%7c&gclid=EAIaIQobChMIm7iDy9zL2AIVRLXACh0Ptgl2EAQYASABEgKpU_D_BwE&gclsrc=aw.ds&dclid=CKHG583cy9gCFUmvTwodctELGQ

Quick, easy, fast, and cheap. Paid $3.00 for mine on sale @ Menards.
 
Originally Posted By: barryh
I made my own by soldering a suitable load resistor across a battery connector so that a small load was applied when the battery was inserted. The voltage could then be read off with a normal digital meter. Cost nothing as I already had the parts.

Yeah, if you have some resistors sitting around, you can just use your existing DMM.

I'm thinking something around 10-15 Ohm should work for 1.5V batteries, and maybe 50 Ohm for 9V.
 
You don't even need a resistor, just use an old incandescent flashlight bulb or maybe even a 194 12V marker bulb.
 
So my thinking was correct, a DVM shouldn't be used to check a battery's health and these little battery meters do have a bit of resistance built into them?
The resistor and bulb in series with the DVM are great ideas.
 
Status
Not open for further replies.
Back
Top