Protected battery?

[mgmrick]

How can you tell if batteries are protected? I have a pair of cr123a 3 volt 1250 mah blue batteries. The outside skin has an indent near the top positive side. I thought that meant there is a protection chip there then?

 

[WillyB]

How can you tell if batteries are protected? I have a pair of cr123a 3 volt 1250 mah blue batteries. The outside skin has an indent near the top positive side. I thought that meant there is a protection chip there then?

Nope it don't. All cells have that top ridge in the can, there is some stuff in there, like the PTC and the terminal that you usually see, but that's not what we are looking for.

Not protected.

Protected, look at the bottom of the cell.

The actual protection circuit goes on the bottom, and there is a strap that runs up the side to the top to complete the circuit.

And here you see the actual PCB.

That's why protected cells are longer,

 

[mgmrick]

Thank you for the very detailed info....very helpful