How long can you store semi battery for ?

Depends on the brand,,,I just had a ENERGIZER battery last 10 years,,,used only 4 months of the year.
STORING ON A BOARD IS A MYTH, HAS NO EFFECT

 

Hey, batteries aren't cheap anymore, with car batteries going for over $100 bucks for the cheapest ones. I'd get one of those battery tenders for $20 bucks.

 

no exact life span can ever be given, only what some people have experienced.

keep it clean, keep the fluid level up by using distilled water, (if it has removable caps), keep it in a cool dry place, keep a Battery Tender (aka a trickle charger). i'd keep it off the garage floor, the concrete absorbs the outside temps, carries it across the floor, I KNOW THAT from my garage days. keep it up on a work bench, or shelf unit.

no 2 batteries from even the same manufacturer will have any guaranteed life span, when not in use, or in service.

 

Let me tell you MY battery story ( hey, gather 'round, an old timer is talking) This was many years ago,( early 80's) and not sure it's the same today, but how different could it be. I was dispatched to pick up a load of lead bars from Herculeneum, Mo. ( south of St. Louis) going to Globe Union in Milwaukee, the then biggest maker of lead/acid batteries. I get to the place, weird town, no grass or trees, they wouldn't let you away from the dock, this guy brings out 7 "bundles" of ingots. Puts 4 in the front, big space, and the 3 remaining in the back, which I had to nail to the floor. I said, "that's it"? He said, well, you got 44,000 there. Who would have thought lead was so heavy. So I get to Milwaukee, the guy says, be right there, and I'm noticing all these empty battery casings on the dock. They were all there, Texaco, Standard, even DieHard. I said, what's the deal here, the guy said, get your best deal on a battery, inside, they are all the same, with proper rating, of course.