over charged house batteries

[Cptrbbjr]

We have a 2011 R27 that is new to us. The house batteries have been overcharging to the point of becoming extremely hot and smelling like rotten eggs. This happens with the charger switch in the on position and/or while traveling. Any ideas out there????

 

[knotflying]

How old are the batteries? Bad batteries have excessive sulfation and cannot be brought up to charge and the charger keeps trying hence the batteries can get hot and you get that sulfur smell from over charging. I suspect this may be the problem because you are getting the same symptoms even when the alternator is charging them. I doubt you have a coincidence of a bad charger and bad alternator regulator.
The smell is hydrogen gas and is very explosive so you need to address this issue right away. I would not use the boat or charger until you get this issue resolved.

 

[Cptrbbjr]

Knotlflying, thank you for the feedback. The batteries appear to be original equipment - so five or six years old. Age could definitely be an issue. Everything is isolated and we plan to work it this weekend. The house batteries are the blue Optima 31s. Any recommendations for the replacements?

 

[doke01]

Bad batteries. Get them off the boat quick. Normally doesn't hurt the charger as long as you replace them quickly.

 

[knotflying]

Knotlflying, thank you for the feedback. The batteries appear to be original equipment - so five or six years old. Age could definitely be an issue. Everything is isolated and we plan to work it this weekend. The house batteries are the blue Optima 31s. Any recommendations for the replacements?

You will get many opinions and each has its own merits. I am a simple flooded battery proponent. You can buy Walmart deep cycle flooded for about $87.00. I replace mine every three years regardless. They have a one year full warranty. AGM have their place in an environment that requires putting them in at any angle required. An AGM battery can fail just like a flooded if abused and there are numerous reasons why you may accidentally abuse your batteries. So, would you rather spend $275.00 or $87.00 to replace a battery. I can replace my flooded every 3 years and get 9 years for the cost of an AGM. Can an AGM last 9 years, maybe?

So I would go flooded and replace all batteries at the same time. And make sure your charger is set for flooded batteries when you do the switchover.

 

[NorthernFocus]

...The smell is hydrogen gas and is very explosive so you need to address this issue right away...

Half right. Hydrogen is potentially explosive but it is odorless. The rotten egg smell is the other product of the reaction which is sulfer dioxide. Not to be anal about it... 😀

While it's true that hydrogen reacts very easily it is also true that it must be trapped in a confined space in order to explode. Luckily it is the lightest of all gases (roughly fifteen times lighter than air) and dissipates very quickly. So in spite of all of the rhetoric on the topic, it is highly unlikely that one's engine room will explode. But.... when flooded type batteries get in really bad shape and the liquid level goes down, the battery case itself provides just the confined space needed for a hydrogen explosion. Not only that, but the energy/heat from the charging process provides just the necessary "spark". Still not likely to blow up your engine room or blow a hole in the side of a fiberglass boat. But violently bursting a plastic container containing a few pints of sulfuric acid is likely to be a pretty ugly event.

 

[snydzy]

Hold on......AGM batteries are specialty batteries that typically only cost twice as much as a premium wet cells. However they store very well and do not tend to sulfate or degrade as easily as a wet cell. There is little chance of a hydrogen gas explosion or corrosion when using these batteries; these are the safest lead acid batteries you can use! If you want the best, most versatile type, consideration should be given to AGM batteries. If you don't use or operate your equipment daily, AGM batteries will hold their charge better that other types. If you must depend on top-notch battery performance, spend the extra money. The UB121100 AGM batteries on my boat have performed flawlessly for 4 yrs now and our still very strong with a minimum of maintenence. They deliver the best performance if recharged before being allowed to drop to 50% of their discharge rate. A UB121100 GROUP 27 - 12V 110AH FL1 TERMINALS SLA BATTERY on Amazon costs $193.98 with free shipping....

 

[CAPTCRUNCH]

Still not likely to blow up your engine room or blow a hole in the side of a fiberglass boat. But violently bursting a plastic container containing a few pints of sulfuric acid is likely to be a pretty ugly event.

Exploding battery raised a good-sized lump in the hood of my 1972 Mercury Capri and released a few naughty words from the witnesses. I assume the battery compartment on an R27 is well enough vented to the atmosphere to prevent much H from accumulating in the boat, but, if not, .....

 

[knotflying]

Hold on......AGM batteries are specialty batteries that typically only cost twice as much as a premium wet cells. However they store very well and do not tend to sulfate or degrade as easily as a wet cell. There is little chance of a hydrogen gas explosion or corrosion when using these batteries; these are the safest lead acid batteries you can use! If you want the best, most versatile type, consideration should be given to AGM batteries. If you don't use or operate your equipment daily, AGM batteries will hold their charge better that other types. If you must depend on top-notch battery performance, spend the extra money. The UB121100 AGM batteries on my boat have performed flawlessly for 4 yrs now and our still very strong with a minimum of maintenence. They deliver the best performance if recharged before being allowed to drop to 50% of their discharge rate. A UB121100 GROUP 27 - 12V 110AH FL1 TERMINALS SLA BATTERY on Amazon costs $193.98 with free shipping....

Talking batteries, anchors and dingys is like religion and politics. Lots of discussion but rarely a change in one's position. No doubt about it that AGM are durable and can be placed upside down . However, many a mariner has accidentally abused their AGM's and they had to be replaced at great expense. One can still get 6 years of use for the cost of replacing the Walmart deep cycle every three years for the cost of the price of one AGM that you quoted. One misstep with an AGM and the cost is beat hans down. I add distilled water to the batteries every six months, minimal maintenance. I can check the status of my batteries with a hydrometer whereas you can't with sealed batteries. In a few years we can probably add lithium batteries to the discussion. 😀

 

[NorthernFocus]

Exploding battery raised a good-sized lump in the hood of my 1972 Mercury Capri... I assume the battery compartment on an R27 is well enough vented to the atmosphere to prevent much H from accumulating in the boat, but, if not, .....

As was the case with your car, hydrogen accumulation in the battery compartment has nothing to do with the battery exploding. It was hydrogen accumulation in the battery itself. But I'll wager the hull/deck of a Ranger is tougher than the hood of even an old '72 vintage auto. After all I doubt you got up and walked around on the hood without causing damage. 😉

But no one is arguing against getting rid of bad batteries. More importantly stop trying to charge them. And most important of all is make sure they haven't been charging for several hours prior to disconnecting the cables to remove them. Don't want to be causing a spark around a battery that's full of hydrogen. Actually that's a good practice to follow regardless of the condition of the batteries. The vapor space is full of hydrogen in any battery that has been charging hard enough to bubble. They should be given time to cool and vent prior to fiddling around with them.

If we keep the discussion going long enough we'll have the OP dialing 911 and requesting the bomb squad to come remove the batteries from the boat 😀

 

[tlkenyon]

The rotten egg smell is actually hydrogen sulfide (H2S), not sulfur dioxide (SO2). It is very toxic, and unlike hydrogen, is heavier than air and explosive. It is indicative of over-charging of a lead-acid battery.

SO2 also has a pungent odor, but is quite different from the very distinctive rotten egg odor of H2S. It is extremely toxic at very low doses. If you can smell it, you are in the danger zone, especially as your sense of smell is dulled by the H2S and you think it has gone away, but it is still there, you just cannot smell it any longer.

Upon initial detection by smell, you must ventilate the spaces very completely and stop charging the batteries. Treat it like gasoline vapors.

I have 30 years in the hazwaste business and have dealt with H2S lots of times from lots of different sources. Not to scare anyone, but it is nasty stuff.

TK

 

[NorthernFocus]

The rotten egg smell is actually hydrogen sulfide (H2S)...

TK's correct. Not sure why I transposed SO2 into the discussion. Also good pointing out the toxicity aspect. Not sure how much a battery can generate but it is nasty stuff. Though the training I've had is that we can smell it at levels well below what's dangerous but the nose is a poor method of determining ppm levels. And when the smell goes away you can't be sure if that's because it's gone or because you're getting toxic levels and your olefactory has shut down.

 

[snydzy]

Knotflying,
I agree,.....BUT, very few people actually do proper maintenance. Because AGM batteries are valve-regulated, have a slower self-discharge rate, recharg faster, etc, etc, they are more resilient than wet batteries and therefore, in real world use DO last much longer than wet batteries. AGM technology is essentially the same as a lead acid battery. The only difference is the electrolyte is not free to spill, but absorbed. This eliminates the need to maintain fluid levels, thus preventing a lot of premature failure caused by reflectance. But maintenance free does not mean the freedom from having to charge regularly. All lead acid batteries self discharge, and the best way to see longest life is to keep fully charged as often as possible. Maybe you‘ve had some bad experiences with AGM batteries. That‘s unfortunate

 

[knotflying]

Snydzy,

Actually, quite the contrary, I had optima AGM on my last boat and was very satisfied. I have however seen quite a few failures of AGM mentioned on this site and others. So it is an individual call. In my opinion the best application of AGM is if they have to be mounted in an odd slanted location or on a sail boat which will heal over. I think the "sturdy" argument is a secondary feature and after a couple of non-intended deep discharges the replacement cost of an AGM is a consideration. A well maintained battery regardless of type should service you well.

 

[Cutwater28GG]

if you are planning on changing the type of battery chemistry; then Id recommend replacing all batteries as you wont be able to set the charger to charge some of the batteries as AGM vs some as wet cell and you will kill the batteries prematurely.

tis the reason I replaced by original AGM battery with another AGM as I didnt want to replace all 4. (we have the universal 110 AGM's and I found Amazon to be the best deal in the end!)

 

[Cptrbbjr]

Thank you all for some great advice. I replaced all four of the batteries with identical AGM 31s. I will be paying much closer attention to them from now on. Again, thank you.