CONTINUOUSWAVE

My boat's been sitting covered in the backyard for a few months with the battery inside, disconnected. When I pulled out the battery to charge it, I noticed a strong smell of vinegar coming from the battery box.

Should I be worried about a strong smell of vinegar coming from a lead-acid battery?

My particular battery is [a vented flooded-cell lead-acid storage battery].



Thanks

The odor associated with vinegar is acetic acid.

A lead-acid battery uses sulfuric acid.

The smell of sulfuric acid is somewhat similar to the smell of acetic acid.

According to one automotive website, people are known to describe the smell of their battery as being like vinegar.
Cf.: https://autoguysland.com/what-does-batt ... mell-like/

Since your battery is a flooded-cell vented lead-acid battery, some odor from the battery acid may be escaping from the cells via a loose cap.

Did you leave the battery on a trickle-charger for very long period, say a month or more?

Perhaps the battery case has been damaged and sulfuric acid has leaked out into the battery box. Check the battery case for damage.

If a battery is left outdoors at extremely low temperatures with a very low state of charge, the electrolyte can freeze, and that can cause the case to crack.

Thanks for the response, Jim. The battery has been sitting disconnected in the boat for a couple months. It is possible it got very very warm, but not that it got extremely cold (California).

I went to check for leaks but couldn't find any. However, when moving/turning the battery there is an audible "sloshing" of liquid inside. Should I try to open the vent caps and top it off with distilled water? Any danger in doing this?

Thank you.

Adding water to a lead-acid battery electrolyte dilutes the concentration of the acid and reduces the electrical stored charge in the storage battery.

If the electrolyte level is low, water should be added to restore the electrolyte to the proper level, and then the battery should be charged to increase the stored electrical energy. When adding water, use distilled water, not tap water or well water. Monitor the battery terminal voltage with a very accurate voltmeter to assess the charge level.