Battery resistance

Hey guys I know there is posts and threads about this but I just want to be clear and clarify.

I checked ir of my batteries via light bulb method and watt meter using correct formula as I don?t have a specific gadget to measure.

My findings were highest ir total on one battery, 82.5 milli ohms then divided by 3 (3s packs) which gave me an average of 27.5 per cell.

My other findings were lowest ir total on one battery, 48 milli ohms then divided by 3 (3s packs) which gave me an average of 16 per cell.

Question is are these batteries toast and should I be looking at total ir or individual cell ir, and what?s the maximum ir before looking at disposing these batteries? At the moment I don?t have the funds for new batteries so should I keep using them?

I just bash but in saying that I do go wot in an oval configuration and do time my runs so at rest my battery individual voltages are at 3.8volts.

I use IR ans a measure of health between cells. My Hyperion chargers provide me with individual cell IR readings so that's easy. If I see an outlier, I know something is wrong with that cell and I can retire the battery before it becomes a fire hazard. I'm also able to use IR readings to monitor the overall health of a battery because I know that the initial readings were when new and can reference all future readings to that point.

You have only a single data point, averaged across all three cells. Are the two batteries you measured the same make, model, age, with approximately the same number of cycles? If so, you could then compare your one set of readings and conclude that the pack with the lower IR was indeed healthier.

Yes fweasel, the two batteries are identical (turnigy Nano techs) with pretty much the same cycles in them.

I have done an ir reading on another identical battery which is a few years newer with less cycles on them and it gave me an average ir reading of 16 milli ohms also (the same reading as one of my batteries in my first post). I do understand what you are saying, that I do not have a new battery to compare this to and that I’m averaging the cell resistance. I’m still learning every day about fe.

I guess I need a proper ir reader and to check ir from new to give me a better gauge of battery condition.

The batteries with higher resistance are coming back in puffed after a run, with a temp reading of 50-55 degrees celcius (about 10 degrees hotter than batteries wth less ir) but do go back down in size but not completely and do feel softer than some of my better batteries.

I think I have read anything over 25 milli ohms the pack should be retired.... are we talking total pack ir or an individual cell ir?