I’ve currently retrofitted my Cal39 with a Link20 battery monitor, 100amp hr. alternator and the next natural progression for my DC electrical management system is to upgrade my battery system. I in the process of installing two 320 amp hr. 6 volt batteries hooked in parallel to augment my electrical system.
My question is: The size of these 6 volt batteries warrants the proper installation into a locker in my aft cabin. I’m concerned about the presence of corrosive hydrogen sulfide (?) vapors off-gassing (during charging) into a living space. Should I install a vent to ventilate the locker? The existing locker does have “secure” cover as well as a cushion over the top of the locker…Any suggestions would be greatly appreciated. Kevin S.
Hi Kevin: The first thing I would suggest is adding HydroCaps (George Peonni, 603 659 2666) to the batteries. This will cut down on water consumption and gas emission. The issue of sealing the locker and venting is tougher. Ideally, the area would be sealed and vented to the deck, as the hydrogen gas is potentially explosive (remember the Hindenberg!). However, sealing and venting introduces other risks such as a flashback explosion or fire in the vent line, as the hydrogen is then concentrated.
We’ve wrestled with this problem many times in the past and from a safety standpoint have always come down on the side of no venting–so that the hydrogen gas was free to drift out of the boat and, assuming the boat was well ventilated, find its way outside before reaching a potentially explosive mixture. This is what the Trojan Battery company recommended to us as well.
As to the corrosive effects of the gas–using Hydrocaps, this has never been a problem for us in our keel areas, where our battery banks are typically installed. Therefore I would guess it is not going to be an issue for you. If you do not have space for Hydrocaps (they add a couple of inches to battery height) then I’d just leave things well ventilated (i.e. the locker door open partially) and see what happens. Odds are you will be OK. Also, just to be safe, make sure there are no ignition sources within the locker itself.
Posted by Steve Dashew (November 30, 1999)
