Storing flooded lead acid battery

Is this a "sealed dry charged" battery from the factory? If so, you can store them for (typically) up to 18 months.

Storing in cool temperatures should slow the aging process. For every 10C/18F below 25C/75F, the battery should age 1/2 as fast. Conversly, for every 10C/18F increase in storage temperature, battery will age 2x faster.

If this is a flooded cell lead acid battery that has been filled then electrolyte levels went down below the top of the plates (low electrolyte levels), then oxygen may have damaged the exposed plates and the battery is usually not used again.

If the battery has not been charged for storage (flooded cell lead acid) roughly once per month--After ~1 month it will start sulfating faster and faster. After 6-12 months of storage without charging, the battery is probably sulfated and not recoverable.

That is the basic answer(s). You can always try to put some distilled water back into the low cells (only fill them 1/2 full at most), and recharge/test and see what happens. Once batteries are recharged and warm, then add distilled water to near top mark of cell (adding water to "cold cell" until "full", the cells become warm/full of gasses from charging and can push out the top of the cells, making a mess and losing electrolyte).

-Bill