Old Eneloops?

I just found an unopened package of Eneloops I bought at Costco almost a year ago. Should I just open them and charge them or try to exchange them for a new set? I don't know if they've lost any life by sitting for a year.

They are fine, just discharge them then charge them up.

That seems to be one of the great advantages to LSD cells, eneloops anyway. They haven't been in production long enough for any cell to have "died" in an unopened package!

Dave

Mr. Happy recently opened a new pack that had been sitting for 3 years.

They had 75% of their original capacity.

Crack that pack open and use them.

hopefully you'll do a nice measurement on one of them to indicate how much charge was left in it?
ie. don't charge it up but discharge it under known conditions to note initial voltage, run-time, drain, initial capacity

Linger said:

hopefully you'll do a nice measurement on one of them to indicate how much charge was left in it?
ie. don't charge it up but discharge it under known conditions to note initial voltage, run-time, drain, initial capacity

Click to expand...

I'd be happy to, if I can. I have a Lacrosse BC-900 charger and I know it gives initial voltage (I can confirm with a DMM). The charger has a "test" function that i can run if it's helpful to anyone.

edit: The first 4 have a stamp on them of 08 11U0 which works out to exactly a year old. All four are at 1.32V (BC-900)/1.319 (DMM). I was surprised that they all had exactly the same voltage with my meter. Pretty good consitancy after sitting in the package for a year. Now they are running through the test cycle at 1000mA charge rate.

hoffmand said:

All four are at 1.32V (BC-900)/1.319 (DMM). I was surprised that they all had exactly the same voltage with my meter. Pretty good consitancy after sitting in the package for a year.

Click to expand...

Yes, that's quite usual for eneloops. It's a sign they are manufactured to high standards.

I recently (couple of months ago) purchased my first Eneloops AAA. Based just on rough estimates, they had at least 60% charge remaining. They had a printed date of 2006-10.

The store might still have some. I'll have to check later today. How would I more scientifically determine the batteries capacity ?

Kueh said:

How would I more scientifically determine the batteries capacity ?

Click to expand...

You would need a battery charger/analyzer such as the Maha C-9000 or a hobby charger that can discharge NiMh cells.

Dug out my old BC900 .....

Eneloop AA 4 pack date 2006-09, charge rate @ 200 mA

Cell 1 2 3 4
Init V 1.28 1.28 1.28 1.28
Term V 1.48 1.49 1.47 1.48

Delta mA 648 1046 590 823
Time H 3:22 5.26 3.04 4.16

Charge Test @ 500mA

Ah 2.02 2.01 2.01 2.03
Volt 1.48 1.47 1.46 1.46

Just FYI, I'm still digging through old posts.