Maintenance Free Battery

trantor12020 · #1 (**permalink**) 12-22-2007

I've just installed an aircon to my H326 and realise that when running the aircon, I can smell the gas from batteries charging. I think I should change to Maintenance Free wet type (sealed flooded cell) but is uncertain if this type will gives off gas during charging. Any advise ?

sailingdog · #2 (**permalink**) 12-22-2007

Umm... How can you smell the gas from the batteries charging? Maintenance free batteries are fairly well sealed and the only gas given off during charging is Hydrogen gas, which is both odorless and colorless.

Whatever you are smelling probably isn't battery gases...

Freesail99 · #3 (**permalink**) 12-22-2007

Dog, I think you misread what he said, or I am. I understand him to have wet cell batteries now and is looking at changing to Maintenance free batteries.

camaraderie · #4 (**permalink**) 12-22-2007

What the auto industry has termed "maintenance free" are really just flooded cells with valve regulation:
"Maintenance-Free batteries (VRLA batteries) rely on valves fitted to each cell. Normally any hydrogen and oxygen produced in the cell will recombine into water, but malfunction or misuse may cause gas to build up inside the cell. If this happens (e.g. by overcharging the cell) the valve is designed to vent the gas and thereby normalize the pressure, resulting in a characteristic acid smell around the battery."

They are definitely NOT a good idea for sailboats. What you want for true maintenance free deep cycle use is an AGM (absorbed glass mat) or Gel type battery AND a charging system that can adapt to their specific charging needs. This MAY be what you are thinking of given the language difference from country to country...but I wanted to warn you off from "liquid" maintenance free batteries as a sailboat solution.

sailingdog · #5 (**permalink**) 12-22-2007

True...but the gas from wet cell batteries is still hydrogen and doesn't smell. If he's smelling an odor, it ain't hydrogen gas.

If the batteries are being overcharged, he may be smelling the acid spilling... it would help if he said exactly what he is smelling... and what kind of battery charging setup he has. A proper three-stage smart charger wouldn't be overcharging the batteries to the point that they're boiling electrolyte and spilling out of the vents.

As for maintenance free.. what he should look at are AGM batteries. IMHO, Gel batteries are far more sensitive to charging problems and seem to combine the worst of both worlds... AGMs are far better.

Quote:

Originally Posted by Freesail99

Dog, I think you misread what he said, or I am. I understand him to have wet cell batteries now and is looking at changing to Maintenance free batteries.

Idiens · #6 (**permalink**) 12-22-2007

It could be the smell of chlorine, if the acid is getting out of the batteries and reaching salt. But more likely, I think, is that the new aircon is leaking whatever its working fluid is.

sailingdog · #7 (**permalink**) 12-22-2007

I'd have to agree with Idiens... since I don't see how merely adding A/C to a boat would cause the batteries to make gases that they didn't make previously, so it is more than likely that the smell has to do with the newly installed A/C system instead. If the A/C system has vents and ducting, it could be from something in the ducting or vent system.

trantor12020 · #8 (**permalink**) 12-22-2007

I'm currently using flooded cell (car types). I've Protech-4 charger and set it to Flooded Cell. Normally when put on charging with hatches all open, I can smell some gas (not H2, probably acids) but not much and not a problem. That's normal for this type of battery. Now with aircon running and all hatches closed and running the charger the acid smell gets to be a problem. On my friend's H33, he fitted a force draft from battery compartment to the heads where the gas can be vented out. On my H326, its not easy to do that so now I'm looking for battery that doesn't emit much or any gas.

sailingdog · #9 (**permalink**) 12-22-2007

Go with AGMs then.

Idiens · #10 (**permalink**) 12-22-2007

Lead Acid batteries don't stink. However, if sulphuric acid gets out and meets salt water it forms chlorine (which is deadly) but easy to smell, like strong chlorinated water in a swimming pool, or bleach.

I really think your AC is leaking working fluid and probably smells sweet and sickly. - But that depends what it uses.