Charge Voltage indication of Cell age?

I've been charging a lot of batteries with the TP4056. I know people have mentioned that some don't charge all the way to 4.2 volts. I believe based on the datasheet,the chargers work by outputtingclose to 4.2v (4.18- 4.20) and stop charging when the battery will no longer take a certain amount of current. (looks like 100ma).

I have a wide range of 'fully' charged batteries from 4.11 - 4.20. all from the same TP4056 charger. My assumption is that newer/healthier batteries will have a higher voltage than the older ones.

Is this is the case? seems logical.

Hrmmm, interesting theory. We need more people to replicate the results and do capacity checks.

Good Point! Maybe that's why the Red Sanyos get hot at the last leg of charging(?)

I'm not sure but I think of it.