Tiny polymer batteries- dead so soon?

[purduephotog]

Good Morning-

I purchased 2 Li-Ion (similar to this: http://cgi.ebay.com/NEW-TWO-BATTERY-FOR-OLYMPUS-STYLUS-1010-1020-1030-SW_W0QQitemZ390087038501QQcmdZViewItemQQptZBatteries_Chargers?hash=item5ad2ffd625&_trksid=p3286.c0.m14 )

They worked fine for a while, but never had the capacity as the original battery (go figure).

Suddenly all three batteries (both the Olympus and the generics) have started dying when inserted into the camera. I've checked the batteries coming off the charger and they read 4.03, 4.08, and 4.12. I've taken the charger off the wall, let it sit for 30mins, put the battery back in and it shuts off.

Now we used to be able to go for over a week on these cells- now we're swapping them in and out in a day.

Any suggestions (short of buying a dedicated hobby charger) to look for to see if they're dead? The cells are under a year old which means, at most, 120 charges per cell.

And yes I can buy more... but if the charger is giving me fits then all that'll do is kill the next batch.

 

[VidPro]

they might "self discharge" for you :shakehead if they are bad, that would give you some indication.
you have a meter i assume, so without a device that does all the work for you, you can still test the capacity.

just hook up some sort of load, a Led, a bulb, a motor, or just a resister, then read the Amps that the "load" is using, and in a few hours you can have a very good idea of the capacity. and if its off by 100ma here and there , who cares, they are either going to have some ability to run something for a while, or they are dead, and in short time with little costs of any sort beyond a simple meter, you could potentially discover it.

even hook it up to the right flashlight head as a load.

try and keep the load at or below about 1/2 the total capacity you think might have ever existed in them, so putting the right resister in for a high powered led, or the right size of bulb or the right ammount of resistance is all the "math" you need, and with small cells like this you can do a bit of guessing, and hoping and testing, just dont flat out short it.

for checking the charge level, if they have any of the voltages you listed after charge, they are ~80% charged, because with li-ion you can get a Loose idea of the charge level just by the voltage .
In the same respect if the voltage is just going down by itself, then you can see that pretty quick with just a simple meter. If the voltage goes down in a few hours, then they are really dead, if the voltage goes down in a few days then they are just Mostly Dead :-). remember some meters will take some power when connected, so when testing for "self discharge" and the voltage going down on its own, test it, then a few hours later test it again, as opposed to leaving the meter on it.

thier dead, you know it :-) with a few steps and minimal costs of any sort, you can prove it in a few hours.

side notes: more often batteries like this are not actual "poly" style of li-ion but rectangular canned li-ion cells.
with other chemistries the voltage droping when removed from the charger doesnt nessiarily mean the same thing, and even li-ion might have some small voltage sag when just "hot off the charger" , so the testing has to take any charging or loading into account.