What do the numbers and codes mean on a eneloop battery?

Eneloop numbers:

The numbers 1, 2, 3 and 4, as in HR-3UTG /BK-3MCCE /BK-4HCD are simply stating the size of batteries. These numbers are used on all batteries in Japan.

  • 1 stands for: D
  • 2 stands for: C
  • 3 stands for: AA
  • 4 stands for: AAA

単三 : Tan-San (san means three) which is the 3rd size. But we call these AA.

単四 : Tan-Yon (yon means four) which is the 4th size. In the western world we call them AAA.

Take note that some foreigners get confused while shopping for batteries in Japan because of a mixup between size 3 = AA and size 4 = AAA.

BK-3MCC code

Panasonic eneloop coding worldwide.

Made in Japan vs Made in China 

When you look closely to the overview page, you can see that from 2013 Panasonic started coding their batteries differently specifiying the market region.

I will take the AA verions as an example.
Code  and market:

BK-3MCC = no additional letter, Japan only  (produced in Japan)
BK-3MCCA  = North America and China (produced in Japan)
BK-3MCCE = Europe/Russia (produced in Japan)
BK-3MCCE = South America, Souteast Asia, Australia/New Zealand (produced in China)

If you are not sure whether they are made in China or Japan, take a look at the Specifications, and if they are not there, look at the packaging. The correct specs can be found on my Overview page.

Reading the manufacturing date:

On the side of every original eneloop battery you can find a date code embossed. You can decipher it. (if yours doesn't have any, yours are likely fake)

The embossed code doesn't have any color, so you need to look up real close

For example the following code: 16-08 xx

the first 2 numbers indicate the year: 16=2016

the next 2 numbers indicate the month: 08=August

So this battery is a 4th generation Panasonic eneloop battery produced in August 2016.

Manufacturing date