HKJ, maybe I just don't understand it well, but in this thread you mentioned that the health of a battery can be determined by monitoring internal impedance such as with a SM8124 meter, but in other threads, I thought you said that measuring internal impedance with a meter such as the SM8124A is only good when first receiving batteries and that only the DC method can measure the true IR as the battery ages? If I understood it correctly and the DC method that chargers use to measure IR are what we should be looking at, then what is the maximum recommended IR of a lithium battery with protection circuits before they would need to be recycled?
Maybe there is no correct answer to my question either as protection circuits add all that extra resistance and from the batteries I have with the same part #, IR has varied greatly as well and left me a little doubtful as to when I should not use them anymore. Right now, the only sane method I trust is if they heat too much whilst charging, then they go to the recycle bin and I'm done with them.
I don’t know if this is a ‘gold standard’ for IR but I’ve found it to be significantly more consistent and accurate than any of my analyzing chargers. If you don’t NEED a hobby charger, and are OK with just discharge and IR testing I’ve found this to be good. ZH-YU ZB106+ v1.3
Note - there are a number of similar testers available with varying prices, power, and cooling options. This one goes from 0.1A > 2.6A. I use and external PC fan to cool it on higher settings.
You’ll need a good cell holder, and a power source. Many charger power bricks will work. Some units are USB powered.
I use this one. There are similar, but it HAS to have the 4-wire capability for IR. 4-Wire Battery Resistance Capacity Test Holder
Thank you flydiver and HKJ! I just wish there was something available that is ready-to-use out of the box, i.e. 4-wire cell holder, resistor and powersource...all in one kit.
The ZB2L3 is not constant current, using resistors for the job. As the voltage runs down, the amp draw decreases. That will make some difference in the capacity (it will read higher), but I prefer constant current.
Does not appear you can do IR with them. I checked them out as a possible extra cheap dis-charger to have and decided it wasn’t worth it, at least for me.
It’s really not too hard to use the links, pick out the necessary items, and purchase. We’ve done most of that homework for you.
When you get to this stage you take a step into Do It Yourself. It’s satisfying, as well as educational and useful. My understanding of my batteries took a BIG step up. A bunch of batteries that ‘seemed’ to be OK using capacity only from an analyzing charger got recycled when IR was found to be (very) high, and they would not sustain amp draws that were reasonable, but the analyzing charger could not achieve.