I got a bag full of old NiMh from recycle, mostly Tenergy Blue 2600 (non LSD), but a few Energizer 2500. They looked to be physically in good shape, almost all were 0 volts. They almost all responded to a couple minutes in a dumb charger with +voltage, then went into my Opus, Lii-500, and LaCrosse for some cycling. Most responded to a half dozen cycles but only up to ~1300-1600mA. The Energizers, which I still have a few of my own and have had good luck with, only made it to ~400-600mA. They will be recycled. Most of these will end up being recycled.
What I don’t understand is the capacity vs. internal resistance measurements. The Tenergys with higher measured capacity seem to have higher resistance say 300-500 measured on the Opus. The lower capacity (1300) have lower resistance in the 100-200 range.
The Energizers that have lousy capacity measure ~90, not much worse than some of my older Eneloops.
To date I’ve equated low resistance with higher amperage support. This sometimes is at the expense of capacity, on new batteries.
OTOH, I don’t understand this paradox of an old previously high capacity NiMh having such a low IR, and negligible capacity. I would think the IR would be VERY high, which is the general trend I’ve seen with NiMh going over the hill. But I have seen some very high capacity NiMh show some very high IR (800-1000), and show decent capacity if used at VERY LOW draw, like solar path lights, which is where I tend to use junk like this.