How do you test that your batteries on the way out?

Batteries and Chargers Rechargeable Batteries
1

Hi all,

I have quite a few batteries that I’ve cllected over time, and as such I couldn’t tell you which ones are 6 months old or 2 years.

So it begs the question- how can I test to see if a battery is still OK?

Is it about the voltage? (that it holds up to 4.2V?).

I’m just getting a little worried about some of my 26650s.

2

http://ztsinc.com/mbt1.html

3

I use a Accucel 6 hobby charger to discharge them and measure capacity.

4

I thought Lithium rechargeables gain internal resistance with age. So if you charge them and they become pretty hot, that means they are old or very used.

5

28.99 +shipping coming from the US. For me it was 35 dollars and got to me 2 days after ordering.

http://www.sierrarc.com/index.php?main_page=product_info&cPath=73_74&products_id=188

6

Put them into storage voltage, measure internal resistance.
Full charge them, measure their discharge capacity at the rate I plan to use them for, 0.5A for example.
Full charge them and measure the charge capacity, pick a current appropriate based on the discharge capacity, like 0.5C at most the original new battery claimed capacity 0.5C.

If they die in 10min on 3A discharge in your flashlight they are probably not very usable are they?

The quick method is to measure their internal resistance.
The slow method is to test their discharge and charge capabilities. It takes forever though.