flooded batteries. what next?

[John B]

A friend just told me his boat flooded the bilge up to the sole. He has 2 house batteries in the bilge( its a deep one) and they've fried. The water" was all brown" so I don't know if thats part of the short circuit process or just the fact that the bilge hasn't been cleaned out for a while.
Anyway, the question. he's pumped it all out and is back this weekend to clean up. what has the short circuiting of 2 12 v batteries done to his 43 ft wooden classic sailing yacht. ? if anything.
is anything apart from fresh water the right thing to use to neutralise any residual acid?

[ 03-30-2005, 08:27 PM: Message edited by: John B ]

[ssor]

Did the batteries flood with sea water or fresh water? Pull them check the specific gravity of the electrolite. If the bilge was flooded with sulfuric acid, neutralize with sodium bicarbonate and fresh water. after about tree rinses taste the water if sour rinse again.
If the batteries flooded with sea water the presence of chlorine gas must be considered. BE CAREFUL!!!

[John B]

yup, sea water it was. good point about the chlorine gas. With an old submariner friend from ww2 I should have remembered that.We discussed it one year.

Greg is still alive after the pumping .
thanks ssor.

[RonW]

In neutralizing the acid, use ammonia, quart or two in 5 gallons of water. The sodium bicarbonate ( baking soda) will neutralize also, but it leaves a gritty film everywhere. I do acid stained concrete and learned the hard way to use ammonia.
Like ssor says, after a couple of rinses taste it.

[ 03-31-2005, 01:07 AM: Message edited by: RonW ]

[sdowney717]

Interesting, my 8D marine batteries have one way valves in the filler caps and screw into the battery. So no water is supposed to ever enter the battery if flooded.
And it did happen on a launch that the water rose over the tops of 4 4D batteries years ago in this boat, but no water got in and ruined them. Do some marine batteries have better sealing caps than others?

[John Bell]

Good news about chlorine gas is that it doesn't last very long in the environment. It's so reactive that it goes away very rapidly. If your friend didn't die immediately, then there's no problem. ;)

Flushing with a base may not be absolutely necessary, either. Seawater is going to have at least some buffering ability and will neutralize any acids. I personally would not want to be have to be below when the bilge is filled with even weak ammonia. Bicarb and a good flush would be less unpleasant and hazardous. How large were these batteries, anyway?

[Dan McCosh]

It's relatively difficult to get water inside a battery through a closed cap, even if the top is covered by a foot or so of water. Lots of batteries are pretty much sealed, and some are in fact completely sealed. The normal vent cap hole is so small little water will enter. Submerging the primary terminals and cables in salt water will create a pretty good electrolytic cell out of the bilge water, producing hydrogen, etc., and lots of electrolytic corrosion in metals. Often the cable itself will often disappear in green muck. Some of the damage observed could be this phenomenon.

[seayou77]

John B, I think that the damage of dumping the amperage into the bilge happened when the terminals shorted. It happened quick. A bath of vinegar might help but a survey might be the best route especially if there is insurance to claim against. I don't think you'll see the damage but if things are unusually green like thru hulls that is a clue.
My battery switches have been located up next to the panel,rather than their original location just above the floorboards.

[ssor]

I agree that there was small chance of getting water into the batteries. Try recharging them, discharging them through a salt water electrolyte wouldn't be as fierce as running the starter motor until they died. It certainly didn't help them but it probably did't ruin them. It was more like leaving the headlights on in your car all day. And definitely look for electrolitic damage, it will probably show as pitting when you have cleaned the crud off.

[chergui]

It's worth reading the Battery FAQ also, if you haven't done so. It is very good and has a lot of useful info in it that everyone with a boat that has batteries in it should probably know:

http://www.uuhome.de/william.darden/carfaq.htm

[ssor]

John, Please tell us what the out come was with the batteries. If this falls on someone else your experience will be helpful.
Thanks,
Ross in Bel Air

[John B]

Ross, the batteries were dead,shorted. He was told by another source that a single 12V unit in that situation could create enough chlorine gas to theoretically kill him but the reality is there was enough "natural" ventilation to not be a problem. I'll ask if there's any on going issues when I see him next.He was going back this weekend just gone.
Moral of the story. If it happens to you, just make sure the hull is well ventilated before clean up.
IE a modest kind of warning bell should ring in that situation.

[ssor]

John,
There are high water alarms for residental basements, battery powered, no water-no power drain. They are cheap, Don't know how long they last in sea water environment.
Ross in Bel Air