Battery date codes

[Bus Driver]

Just replaced the battery in a pickup truck. I buy from an independent dealer who underprices Advance Auto by a meaningful amount and offers a wider variety, such as tractor or larger truck batteries. 7 to 10 years is the usual life of batteries purchased there. This last one failed after just 3 years and 8 months.
The date code on the new battery is J5. That would indicate manufacture in October 2015-- quite a feat of time travel.
How would you explain the J5 date code?


A battery should do well on the shelf for about 4 months before being sold, but prolonged periods at partial charge damage batteries permanently.

http://www.ehow.com/how_5818399_read-co ... eries.html

http://www.premierproductwarehouse.com/ ... e_info.pdf

 

[John *.?-!.* cub owner]

Do not overlook the fact that J5 could also be Oct. 2005, and it may have been shelved a long time. May of the places that sell batteries to the smaller local dealers use them to unload old stock without the local dealer knowing it. Also, most manufacturers use the same or similar code, but it is not mandatory, that may be the warranty end date.