Overcharging can result in hydrogen gas being emitted and if the concentration of it becomes 4%, it could become very explosive. Lead acid batteries are the most susceptible, so if you do not have a battery box when you are charging a lead acid battery, you should be very careful. Most often, the gas is formed when you overcharge a battery. Hydrogen is the gas that batteries put off and all deep cycle or batteries on a high charge will emit it. The extra wall will protect the battery from damage and prevent gases from becoming a concern.
The only time that you really may not need to have a battery box is if you have a double-walled battery on your boat. The box will have many features that protect the battery and your boat, not to mention the fact that they provide a safe vent to divert the gases that may be produced by your battery during recharges. The answer is you may not need to, but it is always good boating practice to use one. Yet still people question whether they really need one if they plan to use a sealed battery. There is also sulfuric acid in these batteries which can be very corrosive. Lead is a very toxic metal that can be absorbed by your body and the environment. Lead acid batteries should be used with a box to prevent acid from spilling out into your boat if the battery becomes damaged. Most all battery boxes contain the battery so that it is not able to shift position by more than one inch in all directions, which prevents it from becoming damaged, even if tipped over. It contains the battery so that terminals cannot come into contact with other metal objects. Battery Box Comparison Chart Brandīeyond diverting potential gases, they contain possible electrolyte leaks or spills that may come from a damaged battery case. This is one of the main reasons they are gaining popularity on boats that have trolling motors. If you have a battery near your fuel tank, that could also pose a problem if you do not have your battery covered. A battery box forms a seal around the battery and directs potential gases away. This is true even if a battery maintains a high charge. If you have a deep cycle marine battery on board, it may give off a gas while running and charging. This serves as a protection mechanism not only for the battery, but those on board. One of the main reasons people use battery boxes is due to the requirement by ABYC Standards in many cases. A battery box keeps battery acid from potentially spilling out.