I purchased this 1990s vintage gold AA Maglite on eBay – which came with two Energizer AA alkalines.
I noticed the date on the back of the blister pack says:
“2/90, ©1990 Mag Instrument, Inc”
I could not see any corrosion on the two Energizer AA alkalines. Out of curiosity, I decided to see if they were still any good.
After opening the blister pack, I checked the voltage:
1.46V
1.47V
Note, these old batteries did not have expiration dates (as current ones do). There were, however, three characters stamped on the side LUA. I could not find any information on whether that's a date code or how to interpret those characters.
I then ran a discharge test on my SkyRC MC3000. As a comparison, at the same time, the discharge test included:
- a new Energizer AA alkaline (exp date 12-2027)
- a new Duracell Quantum alkaline (exp date March 2027)
The SkyRC discharge test was set up as follows:
“NiMH” battery type chosen (per manual when discharging alkalines).
Discharge Current: 100ma
Cut voltage: .8V
D. REDUCE: 10ma. Note, this setting reduces the discharge rate as the battery gets closer to depletion, which takes into account an alkaline’s ability to recover. In other words, discharge rate drops to 10% of start rate.
What we see, is that there was plenty of capacity left in these two 29 year-old batteries.
Old Energizer #1: 1,968mAh
Old Energizer #2: 2,304mAh
New Energizer: 3,252mAh
New Duracell Quantum: 3,463mAh
I conclude that some alkalines have a very long storage life – if stored under favorable conditions (whatever that was in this case, which is unknown).