14500 battery shows near zero on multimeter?

[mandas]

Hi,

I have two Ultrafire 14500 'protected' batteries. Fresh off the charger one shows 4.17 volts on my multimeter. The other one which I had been using for a little while is now showing 0.1 volts?? How can that be and what does that indicate?

The protection circuit didn't fail and allow me to discharge the battery that much, did it? Is it unsafe to put this battery on the charger?

 

[gcbryan]

It didn't fail...it tripped. Put it on the charger until it's fully charged.

 

[tolkaze]

Yeah, sounds like the protection tripped... if you drive the ultrafires too hard too fast, they trip. Put it on charge like gcbryan said, and it should reset the protection

 

[march.brown]

When you switch your charger on without any batteries in it , can you measure a voltage of over 4.2 volts in the battery compartment ... If so , the charger should reset the battery and charge it.

Some chargers only start to charge if the battery has a certain minimum votage ... If your charger is that type , it won't reset the protection circuit ... In this case simply parallel the tripped battery with a known good one for a second or so and the bad battery will reset ... It can then be recharged.

To parallel the batteries , I put a paper-clip between the two negative ends by standing the two batteries on the clip ... Then with another paper-clip connect the two positives together for a second or so.

Good luck.
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