"Toy or Other Not Working After Battery Change"

 By Ron Stultz

10 December 2017

Summary: Believe it or not but the physical dimensions of "standard" batteries like AAA and AA are not the same from every manufacturer. Depending on battery box in toy or other device, new batteries might not be making good contact at "+" ends of batteries because of physical dimension differences between old batteries, replacement, new and how battery box designed.

Background:

Grandson's (3) AAA battery operated toy dead.

Worked for short time day before.

Needed new batteries.

Opened up battery box and replaced the Chinese brand original AAA batteries with new Duracell.

Still dead.

Take cover off switch, wiring side of device and could find nothing wrong.

Time for voltmeter.

Can get 1.6 volts DC from end-to-end of each battery but when measuring between 2 batteries, no volts at all when should have been 3.2 or so.

??

Take out metal strip that bridges 2 batteries out of battery box housing and find strip is intact and no corrosion and spring is not loose.

Replace metal strip but still no 3.2 volts measuring across 2 batteries.

Magnifying glass.

The positive terminal of both AAA size batteries are not touching metal contact in battery box!

Look at old Chinese brand battery and new Duracell and notice that positive terminal on old Chinese brand battery longer than on replacement Duracell!

Because of battery box design, positive terminal can not be forced to contact positive terminal in battery box.

Below shows how positive terminal on new Duracell battery is shorter than Chinese brand.

Is the Chinese brand the correct dimension for AAA or is the Duracell???

Fix:

Thin aluminum sheets, used for roof flashing is sold at various hardware, building supply, stores.

Using a sheet, cut with scissors a strip wide enough and long enough to be pushed into slot in battery box holding the metal, positive terminal strip.

Aluminum strip installed on positive terminal facing side of metal strip.

Aluminum strip provided additional positive contact metal thickness and good contact was made.

Device operational.

You can try:

Don't know. Perhaps if you take one of the dead, old, batteries to a battery store or anyplace they sell batteries, you might be able to find an exact physical dimension match for the dead battery, but good luck with that.