Yes that charger does not tell you anything when it blinks on one you throw the whole set of four in the binOkay I have two of these chargers
I have two sets of four batteries that I have been using since 2020
When I traveled to Indonesia last year I brought eight older batteries to swap out after two dives as I was shooting around 100+ shots per dive usually (macro).
The newer batteries were then charged again and changed once more after two dives.
When charging the older batteries I did notice a charge light blinking when all the other lights had gone out possibly indicating that that battery was on its way out, although when tested it did read around 1.2v IIRC.
The older batteries are no longer used in my strobes as mentioned before.
A battery can read 1.25 and have low capacity I learned this when using the panasonic pro charger that gives me voltage and mah injected in the battery. Sometimes you get higher voltage and lower capacity which is not what you want
on the contrary a battery can still deliver at 1.1 volts for longer time. Remember this battery is charging a capacitor which is what makes the flash happen the battery is simply a current generator
