Battery testing aid

[mklotz]

I sometimes get stuck with the task of sorting out dead batteries from a box of mixed types. [Don't ask; it's sort of a charity task.] I could use a real battery tester but I'd die of ennui so I only check the voltage. Most of the dead batteries are sufficiently deceased that a voltage check is sufficient determination.

If you've ever tried to test a battery using the two voltmeter leads you'll soon learn that you require three hands. I first solved this problem by laying a sheet of aluminum foil on the bench, threading one of the probe tips through it several times. Then one hand holds the battery on the foil and the other hand applies the other probe to the top of the battery.

The probe tip to foil connection was always a bit dodgy so I attached a wire with an alligator clip to a small piece of copper plate. Clip one lead to the plate and proceed as above.

[nickyd]

Simple and clever.
Thanks.

[mklotz]

The alligator tipped wire worked well but I soon became tired of having to clip/unclip it to the VOM lead and having it get tangled with the other wires in the VOM storage tray.

The solution was to fit a small pin plug to the copper plate and wire it to the plate. The alligator/wire is gone and now the VOM lead can be simply plugged into the plate assembly.

[Toolmaker51]

How on Earth could I have Thanked the previous version, only to have it surmounted immediately by the second version!

Because the first was already 100% more effective than my 3-handed efforts.
Now, while I haven't a lot of electronic components on hand, a real good store is nearby. Copper sheet though, no lack of that!

[mklotz]

How on Earth could I have Thanked the previous version, only to have it surmounted immediately by the second version!

Because the first was already 100% more effective than my 3-handed efforts.
Now, while I haven't a lot of electronic components on hand, a real good store is nearby. Copper sheet though, no lack of that!

Since the connector ends up connected to the copper sheet, you can manufacture one for yourself. I only used the connector because I happened to have one to hand.

Take a brass screw and drill it axially to accept the VOM test prod. Mount it on the copper sheet with a brass nut. You may want to rig up a springy bit to keep pressure on the prod so it doesn't slip out of the screw. Imagine a metal washer with a long, springy arm thar arches up and presses down on the part of the prod not inside the screw.

OTOH, if you have some small brass tubing that can be deformed to grip the prod, a piece of that soldered into the hole in the brass screw might work.

[Toolmaker51]

Agreed. No objection to DIY receptacle, or short drive for a commercial one. I like idea of making ground plate become a tool, instead of fiddly business with meter jacks. This applies extra to coin cells, being tougher yet to manipulate.

[mklotz]

Agreed. No objection to DIY receptacle, or short drive for a commercial one. I like idea of making ground plate become a tool, instead of fiddly business with meter jacks. This applies extra to coin cells, being tougher yet to manipulate.

With coin cells one doesn't need three hands. Throw the cell on the plate, hold it down with one probe on the top and touch the other probe to the plate. If the VOM is digital you don't have to worry about battery polarity. Just ignore the minus sign.

If you're out in the field and don't have the copper plate, a coin with a diameter larger than that of the battery works well. No coin, use a washer. Any conductive surface will work.

[Toolmaker51]

Agreed on that again. I referred (un-clearly) to button cell tests vs two probes of a meter.