Shelf life of unused rechargeable batteries?

[NeedMoreLight]

Around 1997, I was at a freight damage store and saw some rechargeable Ni-Cad AA batteries by Millennium. All were laying in a tub, and I thought these would be good for my solar charger, but never got around to charging them. Fast forward to a couple years ago, I ran on to these, and since they were now old, and I now was using NIHMs, I took them to a recycle store.
Last night I was looking for stuff to get rid of as I have way to much junk around here, and looked in my box of rechargeable batteries, and found some newer Eveready and Chicago Electric Ni-Cads in AAAs and Ds. And, found two more of the old Millenniums which now have to be at least 16-17 years old.
Not having anything else to do, I put these in a Ni-Cad charger and after what seemed several hours, the lights went off.
I then put one in a China made 230 lm light, and an alkaline in another one and turned them on. The Ni-Cad ran decent for about 18 minutes then dimmed. The alkaline ran decent for about 40 minutes then started dimming. I put the other Ni-Cad in and got the same result.
Don't have a clue as to the ah of the Ni-Cads, but after this many years, I really didn't think they would even take a charge.
I have a number of NIHMs, (several packs I haven't even opened yet) so I am not sure these would be used even if they were still good, so they may be headed to the recycle store as well.
I ran both of the Millenniums to almost dead, and put back on the charger. Will try them again later.

 

[Lynx_Arc]

Considering the capacity of older nicads 18 minutes vs alkaline is pretty good. I recall nicad AAs having 600-800mah capacity compared to nimh of 1200-1600 capacity for generic and 1900-2500 for name brand with alkalines having about 2700mah capacity at low drain usage dropping as the current demands increase on them getting only double from alkalines shows the nicads are not too shabby.

 

[jhn.holgate]

I had a bunch of NiMH's sitting in a draw for 8 - 10 years or so and ended up buying a C9000 charger to sort them out. Most of the energizer 2400mah batteries came back up to near a full charge after 3 or 4 cycles. Quite a few had the 'high' resistance on the charger and another 20 (mostly generic brands) or so didn't even look like regaining any capacity after several cycles. So I'd say about 3/4 of them didn't last the distance sitting in a draw. I ended up buying a bunch of Turnigy LSD NiMH's from Hobby King at around $1.50 each - when charged up and cycled, they were all within 100ma of their claimed capacity. It's certainly a huge advantage to have a charger that can tell you what it's putting in and what it's taking out - it was all guess work prior to that.

 

[NeedMoreLight]

OK, I am a bit impressed by these old Ni-Cads. After recharging them, they lasted pretty good for about 30 minutes, still usable light to the 35 minute mark, after that I could tell they were getting weak and not much energy left. At the 30 minute mark, they were still brighter than my 1 watt light.
And jhn, I may look into the charger you mentioned.

 

[SaraAB87]

I have a sealed package of 2 eveready C cell Nicads dated 1999 here that I picked up for like 50 cents. I like to keep obsolete stuff around in case it becomes worth money but I don't have a C cell charger for these so I can't test them. I wonder if they are any good.

 

[NeedMoreLight]

Sara, I too keep oddball stuff. One never knows.... I have some batteries on the charger, and when they are done, I am going to try the Ds, AAAs, and a pack of Radio Shack Cs. The Ds have 9540 stamped on them, that may be a date code, but not sure.