Are all these agm not factory filled?Quality control dictates battery life as well. How many have you seen that were defective right out of the box ? I'll guess a few.
The likelihood of that happening with a really, really cheaply made battery is exponentially higher.
The initial service is critical - fill, let sit so the cells can soak, then put on a slow charge (tender) until ready.
I worked for a company that was getting ridiculous warranty requests from two separate dealers for wet cell (good quality) battery failures.
We did an audit, and found they were using it as a 'free battery promo' for anybody who brought one back regardless of age or condition.
They were also making just plain fraudulent requests, then putting the replacements into inventory to be resold at a later date.
Not that it has anything to do with the topic at hand, just sayin'...
Sent from the future