It isn’t hard to identify the date code of Sanyo 18650 battery.
The logo “Sanyo”, the model “18650…”, and the battery date code such as”O49A” are stamped on the PVC of the battery. Please noticed that the codes are stamped, but not printed.
Here below is the picture of stamped logo.
Stamped date code.
How to read the date code of Sanyo 18650 battery?
1. The first letter = year. K =2006, L = 2007, M = 2008, N = 2009, O = 2010, P = 2011, Q = 2012, and so on. For example, on the picture above, “P” means the year of 2011.
2. The latter 3 numbers+letter = week. On the picture “41A” means the 41st week.
Inclusion, the Sanyo battery on the picture is maded in 2011, the 41st, week.