I read this post with interest and remembered, that I also have a 9AN Commander and two of those NiCad sticks. Quite like "new", at least not used much. Let's measure.... 1.67 Volts, not completely dead, so I decided to try to wake it up gently with just 100mA of charging current from my laboratory power supply. That has worked fine, then number two... more than 2 Volts! That one was also revived successfully. They must have been around for 15 years, unused, never charged for such a long time. I even have a spare bulb for it. I started to use it now!
I was just meaning: after more than 10 years(!) of just sitting unused, that was the voltage I measured. I expected to see 0.00V here. So I thought I could as well give it a try to wake it up gently. The best way to kill NiCd batteries is to quick charge a battery that hasn't been used for a long time, so I just fed 100mA to it for 24 hours. Charging was done 18 days ago, one of the sticks just gave a faint glow now and was off, the other still holds up bright. I think I will just buy this one:Are you saying it only got up to 2 volts or the full voltage? Either way it won't last. Once they're on the way out, the runtime will be very short and it will drop very quickly just sitting around as well. The 18650 adapters are the way to go. I'm not sure if I 21700 would fit in the body, but I really don't like those batteries anyways. Might be a little much for the bulb as well.