I am powering an embedded system using one 3V Lithium battery.
Two similar devices were acting very differently: when they both were on, the voltage read across the batteries were different (2.9 and 2.78--and of course both completely the same when not under load), even though both batteries had the same voltage when not under load. I thought the two devices are different because of the tolerance of the parts (LEDs, photodiodes, and such).
But when I exchanged the batteries, the behaviour of the two devices (and the voltage across the batteries) also changed, So I concluded this has something to do with the battery.
Now, my question is, how I can single out such batteries? And why do they act like this? And what are the techniques to make this problem go away or less significant?
The battery has a storage life of 10 years and has been produced six months ago, both of the batteries have also been used the same amount