Uneven Battery Drain

[GPB]

I had noticed that my PT Fuel Headlamp was dimming much earlier than I expected so I pulled the batteries to check them and found 2 cells had 1.6 volts ( alkalines ) and 1 was very, very low. So I put 3 fresh cells in and ran it overnight. Then 1 cell was full, 1 was pretty low, and 1 was really low.

So my question is: Should I assume that something is wrong with my light ? In my limited experience with 2 cell lights, the batteries drain at the same rate, and whenever you check the voltage of the cells, they are the same ( or very close )

 

[45/70]

Greg, there isn't any way it could be your headlamp. It has to be you have a bad bunch of batteries. You are correct in assuming that cells, regardless of the number, will drain evenly in your light, so there must be some lemons in the batch.

Dave

 

[GPB]

Thanks !! This time I measured the voltage before I put them in, so I know I had good batteries to start with. I'll see what happens after a little use on them.

 

[Marduke]

Thanks !! This time I measured the voltage before I put them in, so I know I had good batteries to start with. I'll see what happens after a little use on them.

Matching open circuit voltage doesn't tell you anything in the way of health or capacity.

My advice to you is to simply stop using expensive and poorly performing alkalines.

 

[45/70]

Well, with alkalines you can get a "sorta" idea of their condition with a voltmeter, unlike nickel based rechargeable cells, but a test with any kind of real accuracy, will require testing the cell under load, such as with a ZTS or similar tester.

If you have a single AA light that has a simple boost cicuit, without any regulation, you may be able to figure out which cells are weak with it.

Dave