Leaving Dead battery on shore power charger

ArgleBargle · #1 09-02-2012

hi.

My batteries are dead. i new they were going but i thought i could squeeze the rest of the season out of them. i could not.

For several reasons (not in stock, i'm out of town for a couple of weeks, plan to modify battery compartment) i cannot install the new batteries i want for at least one month.

The 12 V system works fine on the shore power battery charger right now with the batteries dead.

I want to leave the 12 V system active just for a fan to keep air circulated and for the bilge pump, both of which are obviously on the 12 V system.

possibly stupid question, but i just don't know: is there any danger to leaving the dead batteries connected to the shore power charger unattended for 1 month?

do you think it would be safer to turn the whole thing off and simply accept the tiny risk of not having the bilge pump hooked up? (the bilge is normally bone-dry and all seacocks will be closed)

any info considered very helpful

cheers!

ParadiseParrot · #2 09-02-2012

Hookup a simple 12v power supply to your bilge pump.
Battery cells can get shorted. There is a fire risk there.

hellosailor · #3 09-03-2012

"is there any danger to leaving the dead batteries connected to the shore power charger unattended "
Aside from possible explosion and fire, no.

Rockter · #4 09-09-2012

A dead battery has a low internal resistance, and if it is truly dead, likely to stay with a low resistance. If so, it will stay warm on charging, it will have a high current draw, and just boil off the electrolyte.
I would not leave it unattended long-term.
Stay with it the first day and night, and check it for temperature and current draw.
If it seems to be tolerating it, it will probably be OK.
Personally, I don't use shore chargers. I have never liked the idea of the electrical system being live while unattended.

lillia28 · #5 10-19-2012

Boiled off electrolyte is hydrogen gas. You know, like they used in the Hindenburg? I don't like the idea of leaving batteries on charge unattended at all!

Lou

Brewgyver · #6 10-19-2012

Wow. I agree that leaving the charger connected to a truly dead battery is not a good idea, but the notion that leaving a normally functioning charging system connected to shore power is somehow dangerous is a bit much. In the U.S. alone, there are likely hundreds of thousands of boats, both power and sail, connected to shore power 365 days a year. I'm surprised whole marinas haven't burned to the waterline.

hellosailor · #7 10-19-2012

Lou-
Not to say you shouldn't be concerned about battery explosions, but it has been well documented for about a decade now, that the Hindenberg didn't blow up because of hydrogen gas. The hydrogen would have vented and cooked off on the top. The real problem--which the Nazis investigated, confirmed, and kept secret since shortly after the incident--was that the Hindenberg had been painted with a special aluminized paint to reflect solar heat. The finely powdered aluminum was pretty much the same as THERMITE, an incendiary. Memo, do not paint your airships with incendiary compounds, they tend to cause conflagrations.

lillia28 · #8 10-19-2012

Aw, come on! You brought up the fire and explosion! I was trying to clarify that Rockter's boiled off electrolytes were in fact hydrogen gas, and that hydrogen gas can be flammable. The Hindenburg reference was by way of hyperbolic emphasis, not a lecture on historical accident investigation! As a pop cultural reference, Hindenburg and hydrogen have been connected for almost 75 years! As a sidelight, Lakehurst is about 35 miles south of here, they are testing new lighter than air ships for the Navy and Army. One flew over the bay earlier this summer. It was erie, looked just like the Shanendoah. You can se e the outline of the Hindenburgh at Lakehurst on Google earth.
T he op asked about leaving his dead batteries hooked to shore power and I still don't think its a good idea. When I was younger, I worked in a garage. The flash when a tech walked past a charging battery was
Sobering. And while aluminum powder is an oxidizer, ever see a car fire involving a corvette? The flames get to 15 or 20 feet. And corvettes are fiberglass! Ok, that was another joke.

hellosailor · #9 10-19-2012

Outline of the blimp? Do you mean the blimpish markings just SE of "Nawcadlke Non-NIF Lakehurst NJ" They look more like a perimeter road that just curves in a "blimpish" way around some trackings on the ground.

What used to be called the Lakehurst Naval Air Station or NAS Lakehurst (IIRC) is actually right under one of the NYC-FL commercial flight paths, and the hangars are quite distinctive when seen from the air that way, but I think Google Earth has "enhanced" ground markings on that one.

lillia28 · #10 10-20-2012

There is a memorial to the Hindenburg, with an outline of the ship where it fell, in chain. Cant get this gd tablet to work,but google lakhurst historical society. Its near t h e big blimp hanger.
The local papers, asbury park press, once claimed the concrete still showed burn marks, but that was a while ago. Every now and then sombody finds a twisted chunk of alumi num and claims its from Hindenburg, some of them prove true. A lot of Morro Castle stuff around also, but less all the time.
The blimp hangers and the catapult test tracks are easily identifiable from the air. Ewr-iad by rj or prop is best, since t hey fly lower. I took flying lessons out of Lakewood, but was always too busy to sightsee!
Sandy Hook is also chock full of history. There is a neat memorial to Lt. Halliburton and crew, killed in SH bay while looking for deserters from HMS Assistance, Dec 31, 1783, when the Brits were evacuating NYC.
Fennimore cooper wrote a novel about priveteers in Atlantic Highlands, which is why AH has so many sailboats named Sea Witch!