Fried Battery Question

[Canibul]

I went down to the boat this afternoon in the marina. I could smell this sort of hydrogen sulfide kind of odor as soon as I got downwind of the engine compartment. I didn't know what it was, exactly. I searched the boat looking for something rotten for a while, then went into the engine compartment. we have four Barracuda brand 12 V105 ah flooded wet cells. Two in each hull, and I can choose either bank or combine them.

I was pretty sure the smell was coming from one of the batteries. It was so hot I could not put my hand on it. The other one felt a little warm, but noting anywhere near hot. And it's sitting end to end with the hot one. All four batts were combined, paralleled, and being charged and maintained by an Outback MPPT 60.

I am assuming that the hot battery and smell means this one has shorted? My question is whether I can just remove it from the circuit and continue with three 105s, in two banks. One battery in one bank ,two in the other?

Or is this a show stopper and I shouldn't do that?

Also, I will never find the same brand battery down here. I will be limited to whatever NAPA sells. Is it okay to put any other 105 ah battery in parallel with the three other identicals from another brand?

[a64pilot]

Your going to get a lot of different answers, but here is my opinion, take it for what it's worth.
You can continue with three batts in different banks, as long as of course your not 24V.
You can replace the bad batt with a different brand batt, but try to keep capacity the same, best in my opinion to replace all batts at the same time, but not critical. I think I would replace that bank, maybe the other one is damaged too? It's just one other battery, a lot depends on what kind of sailing you have coming up.
I would try to determine why it failed if possible, did it fail, or was it killed?

[Canibul]

How do I determine that? Boat was hit by lightning on the way down, fried everything from the VHF on the mast to the alternators. The batteries have been run down to nothing at least twice that I know of since then. The boat has been sitting in the marina since October while I refurb it. Batteries have been seemngly fine, keeping topped up with the solar, for over a month now.

[a64pilot]

Only way I would know how would be to check voltage and current during a charge cycle, but I'm solar stupid, need a smarter person than me to tell you how to do that.
I would replace both batts and "watch it" I would watch battery voltage as I wouldn't know what else to watch

[a64pilot]

seeing as how they were all connected together in parallel making essentially one big battery, but only one went ballistic, I'd bet lunch on you have one bad battery, if it were a charger issue, shouldn't all of them or none of them have gone?
One question is are the other three fine, or are they just about to go too?
Me, if money or quality of batteries were a concern, I'd replace one bank, two batteries, that way you should know you have one good bank

[Canibul]

Yes, they've all four been connected in parallel for the past several months. I have an IOTA 55 amp battery charger, too, but it's been turned off since I got the solar working again. I also installed a Vectron battery monitor about three weeks back. I had noticed that the voltage had dropped down from a normal 14.2 to 13.4 yesterday and 12.8 today. Thats for the entire bank. The gauge said that there was 7 amps going in. I figure that was all getting shorted in that one battery. It was seriously hot. I couldn't hold the back of my hand against it

[a64pilot]

I think your right that one bad cell was pulling down the entire bank, and of course it takes a tremendous amount of energy to heat that much mass up. Still if I were going somewhere away from civilization, I think I would want one bank new, if I were going towards civilization, I might just go with three batteries.
But it's real easy for me to say that sitting at home on my couch

[westwinds]

Do these batteries have caps on them for adding water? If there is, you can take something called a hydrometer (Dorman makes a good one) and check the hot battery cells. All a hydrometer does is check the density, the specific gravity, of the battery fluid by measuring how high a float goes in the battery fluid. There's a scale you read on the float to see how dense the fluid is. This is important information because it tells how much power is left in the battery. If the density is low, meaning there is less sulfuric acid, the cell has less power. What can happen is the active material on the battery plates can come off the plate with age. This material falls to the bottom of the case and when there is enough of it, the plates can touch this material shorting out the plates and then you have what is called a dead cell. A twelve volt battery has six cells, or battery caps if so equipped. Low maintenance batteries to not have caps. Anyway, if you check all the cells, you will find one that has much less of a charge, usually nothing at all, that indicates it is time for a new battery because there is a dead cell.

Generally it is not considered good practice to mix old and new batteries as the old battery tends to go dead faster than the new battery, discharging both batteries a little faster than normal. If you check the cells on an old battery, you will usually find some variation in specific gravity or density of the fluid. When the specific gravity varies by more than .030 then it is time to do what is called an equalization charge. Trojan battery company says charge at 15.5 volts for equalization, but lots of hydrogen and oxygen are produced, so be very careful about sparks. Turn off the battery charger, or unplug it, before disconnecting wires as a spark can cause the battery to explode. Jump overboard if this happens, especially if in the eyes. Best to wear safety goggles as battery fluid is more than 30 percent sulfuric acid, realty nasty. Charge for a few hours at the high voltage and monitor the specific gravity to see if it equalizes. Equalization may not be complete because of material that has fallen off the plate.

About your specific problem, if you have two batteries per bank and one of the banks is just for the engine, then all you need is one good large battery for the engine unless you have an engine of more than 100 horsepower. Diesel engines of around 20 horsepower take about as much power as turning over a V8 gasoline engine so even a hundred amp-hour deep cycle will work. So, swap batteries around so you have two for the house batteries and one for the engine.

Also though, you do not know how well the previous owner was about keeping the batteries charged. If the batteries sat discharged for several month, sulfation has set in where small lead sulfate crystals that occur when a battery is first discharged change to large crystals. Large crystals do not revert to sulfuric acid because of smaller surface area. If all the cells show low specific gravity, and stay that way when you try to charge the battery, then you need new batteries. Sometimes a recommendation is made to charge at an equalization voltage, but I have found this does not help. Best to charge at 14.4 volts which is the voltage where the water breakdown into hydrogen and oxygen just starts to occur. Given enough time at this voltage, a sulfated battery can sometimes be salvaged.

[bill good]

"Hit by lightning". I would be carefully checking all the settings within the menu of the MX60 & resetting if necessary. If you disconnect the hot battery & recheck the performance of that battery after 24 hrs or so & it is OK you may be good to go. If nothing is using power or the load is very light I would be only using the float charge setting of 13.7V. Stay away from high voltages above 13.8V until you work out what went wrong. The MX60 on my boat has just damaged expensive cells due to a menu change that happened without my knowledge!!

[colemj]

Pull the bad battery out - no problem with the banks (although I would just put them all into a single bank).

Not a show stopper.

Get a reasonable capacity deep cycle battery of the same type (Flooded wet cell in your case) at NAPA and don't worry much about the age or exactly matching capacity of the others.

This assumes, of course, that these batteries were not the ones originally installed when the lightning struck. If so, they all should be suspect.

When getting advice, keep in mind that others may not be familiar with husbanding batteries in remote tropical places. Places where you cannot always obtain that "perfectly matched" battery bank of exquisite quality batteries, and where individual batteries just sometimes die in this environment even when you are taking such good care of them.

BTW, you have a NAPA? OH! Lucky you! Maybe you aren't as remote as I thought!

Mark

[Stu Jackson]

Good, real world advice from Mark.

[sailorboy1]

Originally Posted by Canibul

All four batts were combined, paralleled, and being charged and maintained by an Outback MPPT 60.

I am assuming that the hot battery and smell means this one has shorted? My question is whether I can just remove it from the circuit and continue with three 105s, in two banks.

You can and should of course take the bad battery out the system.

I would be concerned that all the batteries were connected at the time of the short. Have you disconnected them and checked the voltages of all of them? I would bet that all your batteries are going to fail soon.

[Canibul]

Thanks for all the advice. I cannot see any way to access the electrolyte in this battery, I do have a hydrometer but no way to check the cells without damaging the battery severely, from what I can see.

But it doesn't really look that complicated. Four batteries in parallel. One of the four is stinking and getting scary hot while charging. The other three are not. What else could it be?

All four of these batteries are about four years old, and yes, they were all on the boat when the lightning struck. We no longer use a separate starter battery.

[ontherocks83]

Just pertaining to the shorted battery you can replace just that one and be good to go.

Taking the rest of the history into consideration I would consider testing and possibly replacing all of the remaining batteries. The fact that you said they were all drawn down flat twice, they went through a lightning strike, and the rest of the maintenance history on them is sketchy. I would be very cautious if leaving local waters.

You should absolutely be able to replace just the one and be fine, but be prepared for the others to possibly start dieing off one by one. Now this could be tomorrow or next year. Again if you're staying local risk it and just do the one. If you are going long distances I would strongly suggest doing all of them so you don't get stranded.

[a64pilot]

Maybe it's just me, but with separate banks, I like to stagger replacement, by that I mean buy one bank every few years, keeps the big hit from happening all at once.
If I have two engines, I do the same, have one new, one mid time. That's SOP for a twin engine aircraft if anyone cares, helps spread costs out.