Alkaline Voltage Question

[Phlack]

Hello.

I got a "Low Batter" indicator on my programmable thermostat, so I replaced them with some generic alkaline batteries...two AA's.
In the process, I managed to break off one of the springy tabs on the unit, so the batteries wouldn't make contact with the rest of the metal.

I thereby shoved some aluminum foil into the gap, it made contact.

Shortly thereafter I got the same "Low Battery" indicator.

I replaced them with Energizer alkalines.

Same result, within a few minutes.

Wondering if it had to do with the foil, I took out one of my rare earth metal magnets (as recommended to me a long time back), and put that where the foil was. I no longer have the problem.

I assume the "Low Battery" came up due to a voltage threshhold. Is it possible the aluminum foil would have created a lower voltage due to resistance? I really don't know how that works, and was never very good in circuit theory class.

Thanks
-Mike

 

[MorePower]

I don't think the foil would have appreciably added to the resistance. I'd think that it's more likely that the foil was making contact with some other part of the cell holder and shorting the cells. That would pretty rapidly cause a low voltage situation.

 

[Lynx_Arc]

could be you have a bad connection adding resistance somewhere. I don't think foil is the problem you can try a paper clip to gap the foil to see if the indicator stops. If your batteries measure 1.3v and up for alkaline on most things you shouldn't get low battery indicators.