12 volt battery position

[Al Skierkiewicz]

Originally Posted by Sunshine

That's the first I have ever heard of a safety valve in batteries. Care to share your source?

It's true, even I can learn something new every day

If you examine your battery, you will see a small insert about 3/4" wide running across the top of the battery. The safety valves live underneath that insert, one for each of the six cells. During charging, in particular, heat can be generated within each cell as well as a little gas. The valve is in place should the pressure build to a point where the case could be compromised. Should the battery encounter one of these "high pressure" episodes in the inverted position, some electrolyte could be expelled. This is a rare event but it is simply remedied by charging in the "terminals up" orientation. These batteries also make some water vapor during high current charge/discharge cycles that may also vent through the valves. As more water is lost, battery capacity will be reduced. Our batteries are of the AGM (absorbed glass mat) gelled design. So when researching batteries, some of the info on gel cell batteries may not fully apply to the batteries we use. AGM batteries are less suscpetible to some of the events described above in comparison with the standard gel cell variety.