Not being an expert on battery chemistries etc, I'm not sure about testing lithium batteries. I have AA lithium energiser single use batteries and want to simply test if they are full, low or dead using a passive tester. Using one of the cheaper $5 ones off eBay or from the local store, will they work? They claim to test alkaline and rechargeable but I don't know if something about lithium AA batteries make them unreliable or unsuitable.
So long as the tester puts a load on the cell it should work. The open-circuit voltage of a fresh L91 is quite high, IIRC ~1.8V, but drops quickly under even a light load.
the discharge curve on a Li single use battery is relatively flat and then rapidly drops off at the end of its usable life. a cell may show a relatively consistant voltage level and only last a limited amount of time under a load. http://data.energizer.com/PDFs/l91.pdf
Thanks - so due to the flat curve and then quick drop off, the tester will show the battery as very full even when it's quite close to being empty, and then it'll quickly register as empty?
The main purpose for this is due to using the cells (8 of them) in a 12V power pack. Sometimes the cells don't deplete equally, so instead of throwing away all the cells in the power pack, I can identify the low ones and just chuck those.
the cells should deplete within a range of stability for a multicell setup if all is equal on start of use. when voltage drops to generally 1.2 they are on the way out and will no longer be an equal partner in the pack.
