Powerex NiMH battery date codes?

kpatz

Newly Enlightened
Joined
Jan 6, 2018
Messages
57
Hey folks, I just registered here and this is my first post... I've been reading up on NiMH cells, chargers, etc. and I have a question I haven't found an answer to.

I have a bunch of Powerex 2700 mAh AA cells, and I'm trying to figure out the date codes on them. So far, out of the batteries I've checked, I've found 3 different codes on the label near the seam: 15-03 U3, 15-11 UH, and 15-11 UI.

I found this thread from 2009, but the OP of that thread never got a clear answer. From what Maha told him, the date code isn't printed on the label, but instead on the "PVC tube" (the sleeve)? He cut off one of the sleeves and found no date code. Thread here: http://www.candlepowerforums.com/vb/showthread.php?237541

His date codes started with 07, and mine start with 15, which lead me to believe this is a year of manufacture. Most of these batteries were bought on Amazon in December 2015, but I did buy another couple 8-packs in October 2017. I haven't found any cells with a code starting with anything other than 15, yet. I have some in devices that I haven't looked at yet.

So... does anyone know how to read these date codes? Contrary to what was said in the thread from 2009, I believe these are date codes. I just wonder what they mean (besides the year).

I just got a Maha Powerex MH-C9000 (another reason I found this site), and I've been doing Refresh/Analyze on my cells, labeling them with their actual capacity so I can match them better in devices. For now I plan on grouping them by the codes I did find, so that batteries of the same age will be kept together.

Thanks...
 

SweD

Newly Enlightened
Joined
Oct 14, 2008
Messages
62
Hey folks, I just registered here and this is my first post... I've been reading up on NiMH cells, chargers, etc. and I have a question I haven't found an answer to.

I have a bunch of Powerex 2700 mAh AA cells, and I'm trying to figure out the date codes on them. So far, out of the batteries I've checked, I've found 3 different codes on the label near the seam: 15-03 U3, 15-11 UH, and 15-11 UI.

I found this thread from 2009, but the OP of that thread never got a clear answer. From what Maha told him, the date code isn't printed on the label, but instead on the "PVC tube" (the sleeve)? He cut off one of the sleeves and found no date code. Thread here: http://www.candlepowerforums.com/vb/showthread.php?237541

His date codes started with 07, and mine start with 15, which lead me to believe this is a year of manufacture. Most of these batteries were bought on Amazon in December 2015, but I did buy another couple 8-packs in October 2017. I haven't found any cells with a code starting with anything other than 15, yet. I have some in devices that I haven't looked at yet.

So... does anyone know how to read these date codes? Contrary to what was said in the thread from 2009, I believe these are date codes. I just wonder what they mean (besides the year).

I just got a Maha Powerex MH-C9000 (another reason I found this site), and I've been doing Refresh/Analyze on my cells, labeling them with their actual capacity so I can match them better in devices. For now I plan on grouping them by the codes I did find, so that batteries of the same age will be kept together.

Thanks...

Without knowing, I would wager a guess that the second number is the month of the year, pretty common and standard on labelling. The Uxx could be anything, some internal Maha-reference.
 

kpatz

Newly Enlightened
Joined
Jan 6, 2018
Messages
57
You could be right about the month. The Ux could be some sort of day-of-month code, maybe 1-9 being the 1st to 9th day of the month, then A=10, B=11, etc. all the way to 31. That doesn't matter as much to me.

I re-checked my order history and found that I had bought 2 8-packs in November 2015, one 8-pack in December 2016, and two more 8-packs in October 2017. The codes I'm finding seem to correspond with these: so far I've found 13 cells with 15-03 U3, 5 with 15-11 UH, and 13 with 15-11 UI. I still have some in devices that I haven't checked yet, but the 15-03 U3 ones seem to correspond with the 2 packs I bought in 2015; the 15-11 UH with the pack I bought in 2016, and 15-11 UI with the 2 packs I bought in 2017. Seems odd though that, if that last letter really is day of month, that I would buy some a year later that were manufactured one day after the last set I bought. Maybe the code has a different meaning.

So far all the cells are testing pretty close in terms of mAh ratings: the weakest measured at 2377 mAh (from the 2015 set), the strongest 2485 mAh (from the 2017 set). I haven't run a break-in cycle on any of the cells, yet. I haven't encountered any bad ones yet either.
 
Top