Dead Battery?

[Don Guhr]

Before starting the engine to remove anti-freeze I measured the starting battery voltage.
It measured 11.99 volts.
One website says my battery is only 20 % charged (SOC).
Another site says any voltage below 12.00 indicates that the battery is probably "dead."
Still another site says that the battery 'may" be recoverable. This site recommends removing the caps, filling the cells with distilled water, and charging for 14-to-16 hours.
Do you think the battery is recoverable? If so, is the above recommendation the best way to proceed?

 

[Davidasailor26]

What type of battery is it (AGM, flooded, or gel)? I presume it was sitting all winter connected to the engine? If so, current likely leaked out of it all winter dragging it down to a very low state of charge. Certainly that's not good for a battery, but it _may_ be salvageable. If it's a flooded cell battery, check/fill the water levels and charge it fully. Then let it rest and see if it holds the charge. If it doesn't then the plates are definitely sulfated and the battery's done. If it does hold a charge initially, it may or may not be ok. In the future, be sure all battery connections are completely disconnected over the winter, preferably try to give it a charge every couple of months.

 

[Don S/V ILLusion]

To add to the above, if it does hold a charge, equalize the battery and ch k with a hydrometer to compare sp gr of all cells which will be a better way of determining if good.

 

[JamesG161]

If it doesn't then the plates are definitely sulfated and the battery's done.

Well, maybe not! Unless the Sulfate is in crystal form. If it is still a powder form, a Balance/Boost charge will do the trick. My Inverter/Charger has a Balance mode. Basically it is high continuous charge, for 8+ hours and is recommended to do this at least 2 times a year to reduce Crystal Sulfate formation. Balance means 2 or more parallel batteries and Boost mean just one.

Also if you are the DIY type, you can search the web for "recovering lead acid battery" and the technique is to dissolve the sulfate crystal and start over again.
Jim...

 

[centerline]

Its definitly a dead battery. A fully charged battery should read 12.4 to 12.6, depending on the temps... 12 and below is dead.
but most likely it is recoverable, at least for a few more months.... this happens all the time in equipment that sets over the winter, and the batteries just get charged back up and put into service without any special procedures...
The special procedures could help if you want to know about what stage of its life that its in, and maximize the time it has left, but if its not something you normally do in your routine battery maintenance, this one time will do very little good...
Charge it up and use it.. if it seems to hold a charge then you can perform the tests later if you choose to.

 

[Benny17441]

Nobody could say if the battery is recoverable or not until it is tried. If the battery has fill caps just make sure the electrolyte level is adequate and place a charger on it. About six hours should do to bring it up to a full charge. Take it to your local auto parts store and have it tested (no sense in setting up and conducting your own tests). If the battery is deemed good then equalize it to further regain some of the lost capacity. The fact that a battery may recover just means that it will be capable of performing the basic tasks it was designed for but may not offer the full performance it once did.

 

[corvette]

How do you deal with a dead battery while away from shore power? Likely need some extra long jumper cables?

 

[PeterBld]

To prevent this recurring a solar panel will normally keep the batteries in good shape. We use two 130watt panels with MPPT regulator on each. This keeps all 5 batteries at 13.75v to 14.0v. The regulators prevent over charging.
It does mean you have to check the battery water levels every 3 months.

 

[centerline]

How do you deal with a dead battery while away from shore power? Likely need some extra long jumper cables?

you either have to have redundency, as in another bank you can switch to, or an independent charge source such as a genset or solar charger and wait for the batts to recharge.... or call your towboat/boatUS insurance and get them to come and give you a jump start....

 

[centerline]

To prevent this recurring a solar panel will normally keep the batteries in good shape. We use two 130watt panels with MPPT regulator on each. This keeps all 5 batteries at 13.75v to 14.0v. The regulators prevent over charging.
It does mean you have to check the battery water levels every 3 months.

I do believe strongly in solar power for cruising boats.... but what made you decide to use a charge controller on each panel, rather than both panels running thru a single controller?

 

[PeterBld]

We use power for inverter. Bread maker. Toaster. Etc etc hair drier. So by having separate MPPTs we maximise output from each panel. We also have wind gen on top of the mizzen. So rarely get below 80% of the batteries.

 

[Tally Ho]

How do you deal with a dead battery while away from shore power? Likely need some extra long jumper cables?

I now keep a 12-volt emergency jump start battery on boards....don't ask me why

 

[JamesG161]

I now keep a 12-volt emergency jump start battery on boards....don't ask me why

Excellent back up and they normally have a 12VDC plug to make a portable power supply for air pumps, fans, iPad chargers, aid for those have dead batteries.
Jim...