8D Outgassing; how much is normal?

[Max Simmons]

During my alternator removal procedure last weekend, I opened up the battery boxes to check water levels and just to give everything a visual inspection.* One of the three batteries seems to outgas more than the other two.* There was a small amount of liquid (acid?) on top of the battery.* I don't recall seeing this before.* The batteries all hold a charge well and have had no other issues.* They are approx. 5 years old and I topped off the water levels last season.* Should this be any cause for concern?* Is FF going to come up with some reason for this that will cost me another grand?*

 

[Capn Chuck]

You should really check the water levels about once a month. Once a season will not tell you if you have a problem and if a single cell gets too low it will only get worse over time. You can test the batteries but you will need to bring them up to a full charge and disconnect them from everything for several hours. Then use a hygrometer to measure each cell. Chuck

 

[C lectric]

Liquid on top of the battery is generally caused by:
overfilling one or more of*the cells,
a battery that is on the downhill slope. The battery doesn't come up to the expected voltage so the charger or alternator do
esn't back off.* This can ruin the other batteries.
A faulty charging source.

I agree , recharge them fully, then disconnect them and from each other* and leave for 24 hours.* Then use the hydrometer to test the individual cell electrolyte. Also use a dmm to check the individual battery voltage, not the bank.* The best is the hydrometer*

 

[Chris Foster]

One battery alone outgassing****could*** be a sign that battery is going west and has a shorted cell - which is a pretty typical battery failure mode.* With a shorted cell, you now have a five cell, 10 volt battery - and the 14 volts the charger or alternator applies to it way overcharges the remaining*5 cells, causing them to boil and outgass.

As Chuck & 'lectric state, the hygrometer would show one cell significantly different from the others since it really isn't charging any more.

 

[C lectric]

If you have the polypropylene cases, not likely with an 8D, which are translucent you can actually spot a dead cell.** It will appear markedly different in colour - clearer looking than the good cells.

 

[FF]

Dont worry about a bit of water splashing, as the batts get recharged , the deeper the discharge (with in reason), the bigger the alt the more activity there will be during the hardest charge stage.

There will even be some bubbles as you get to 100% , although this takes a long time, dock side or solar .

As long as the top of the plates NEVER get dry , water as frequently as you are comfortable with.

We easily go all summer (necessary as were 1400 miles away) on 8D batts by over filling the batts before leaving . On our return the water level is usually fairly low , but above the top of the plates , SAFE!

In the "old " days many quality batts were shipped dry , so by intentionally using more water and less acid , the house sets were a tiny bit less powerful, but lasted far longer.

A boat setup trick from John Surette his'self!

FF

 

[Capn Chuck]

If you put too much water is in the battery, when the engine is started, the acid will spill. The reaction inside the battery when the engine is started causes the water level to rise. If there is too much water in the battery, the rising water level from the reaction will cause the water to overflow. This causes valuable acid inside the battery to be lost. The acid is the conduit in which the electricity flows. The acid will cause corrosion if it comes in contact with metal. Putting too much water or allowing the levels to constantly be too low will do a couple of things, shorten the life of your battery, make a mess, and add additional corrosion in areas you don't need it. Maintain a proper level, check it regularly, and your batteries will give you long and faithful service. Chuck

 

[FF]

"If you put too much water is in the battery, when the engine is started, the acid will spill."

Perhaps if the battery is discharged ,

BUT my technique is for a single solar 75W panel (with V regulator) that will be feeding 2-8D's for 6 unattended months.

"add additional corrosion in areas you don't need it."

Most folks take a hint from the Hooligan Navy and use COTS battery boxes, you could take an axe to the battery and nothing would get in the bilge or corrode.

A mess to clean perhaps,

Hamilton Marine has a picture,

 

[Capn Chuck]

Having the water from your battery spill into the box does not prevent corrosion at the battery connections. Overfilling batteries just does not make good sense in my opinion and I would never recommend some one do that. But that is just my opinion. Chuck

 

[FF]

"Having the water from your battery spill into the box does not prevent corrosion at the battery connections."

Nope having a bit of petroleum jelly shmered on the terminals does ,
even stops the corrosion from the usual evaporation and outgassing of battery acids.

 

[Phil Fill]

I would think is would also depend on the kind of caps.* We have three 8 D with push on caps that require checking/filling at least ever 2 months.* *We have three 8 D with screw on caps that last for 6+ months.* The only difference I can see is the caps.

 

[FF]

Folks that don't want to do much watering on hard used bats can get HYDROCAPS .

Look see at http://store.solar-electric.com/hydrocaps.html.

But there created in Miami and can be bought cheaper direct from mfg..

FF