Bulging battery-is it ruined?

[Mitchell87]

So yesterday I had shore power hooked up for about 12 hours. I recently purchase the boat so this was the first time I had shore power connected for an extended period of time. Once the battery banks were charged I noticed the amps coming in had gone way down telling me that power to the batteries was being regulated, so I left the shore power connected. A little while later I notice amps in has spiked and I know that the batteries have been fully charged hours ago as the net amps has been showing zero.

As soon as I saw the spike in amps I knew something was wrong so I ran down to the stbd battery bank and could smell the h2s or whatever it is. Two of my odyssey pc 1800-ft’s were extremely hot.

Ran outside naked no less and disconnected shore power. And turned on my water heater in an attempt to draw out some charge quickly. ( don’t know if this was a good idea or not)

Anyway, after letting the batteries cool for an hour I examined the batteries which were still scary hot and noticed one of the batteries was bulging on the sides. I tried to disconnect the battery, but they are set up with bus bars and wing nuts. When I tried to undue the wing nuts I had a large amount of sparks. Luckily I had vented the area otherwise I fear I could have had an explosion.

It’s 8 hours later and the two batteries that were hot are now just warm. I have not seen any leakage. Will the bulging go down on its own as the gas dissipates out of the battery case? Does a battery that’s bulged and gotten this hot need to be replaced or is it possible that it will be fine as long as I don’t let it get overcharged again? These are $700 battery’s so I’m hesitant to replace as I’d need to replace all five so they have the same start date from what I’ve been told.

[boatman61]

Dump them before they explode.. make a helluva mess of boat and folk on board.

[Pete7]

Any warranty left on them because they are both toast. Some minor scrap lead value, that is it.

Do you really need 5 of them?

Had the same problem with a UPS protecting a server recently. Took it outside and scrapped it the following day. Didn't even take it apart because it had been so hot. Boiling acid isn't something to risk.

Pete

[Mitchell87]

Any idea what caused this? Why would the charging be regulated then suddenly spike? Shouldn’t I be able to leave shore power connected for extended periods of time?

[Shrew]

Originally Posted by Mitchell87

Any idea what caused this?

Most commonly caused by overcharging. Shorted terminals might also be a factor, however I assume the issue is due to overcharging.

Originally Posted by Mitchell87

Why would the charging be regulated then suddenly spike?

Battery failure

Originally Posted by Mitchell87

Shouldn’t I be able to leave shore power connected for extended periods of time?

Yes, absolutely. I've left boats plugged for weeks at a time with no issues.

I would dispose of any battery which swelled. IMHO that battery is now toast. My next step would be to look hard at the battery charger. I would not expect this behavior from a good, properly functioning battery charger that can detect and regulate properly.

This is also brand I'm not familiar with, in a form factor I am not familiar with. The batteries are marketed as 'Dual-Purpose', then go on and on about superior CCA. This sounds like it is more geared toward the Starting side rather than the deep cycle side. If this you your house bank, I would look at Deep Cycle specific batteries, not 'dual-purpose'.

[Jammer]

Originally Posted by Mitchell87

It’s 8 hours later and the two batteries that were hot are now just warm. I have not seen any leakage. Will the bulging go down on its own as the gas dissipates out of the battery case? Does a battery that’s bulged and gotten this hot need to be replaced or is it possible that it will be fine as long as I don’t let it get overcharged again? These are $700 battery’s so I’m hesitant to replace as I’d need to replace all five so they have the same start date from what I’ve been told.

The problem you have is that the bulged battery had a shorted cell. This is a fairly common failure mode. The failure should be covered under warranty.

I doubt very much if there is anything wrong with your charging system.

These are 12v batteries. Do you have a 24v electrical system? If you do, there is the possibility of damage to the other battery that was in series with the one with the shorted cell as it may have been badly overcharged. Perhaps this is the other battery that got hot. A battery dealer should be able to test it. If damaged, it may also be covered under warranty.

There is no reason to replace all five batteries. While it is a good idea to have batteries of the same vintage, it isn't strictly necessary.

[IslandHop]

Could be overcharging due to a bad batt, or reg in the charger. You want all your batteries the same age if they're strung together, only as strong as the weakest link. A bad battery will make the charge go up as it won't take a charge efficiently, then of coarse any good ones will overcharge, heat as a result, and off gas. The lead battery, the one where the positive load is connected, is always the first to go as it works the hardest. A bulging warped case means acid leaks and maybe an internal short as a result. I suggest a small solar trickle charge unit, dirt cheap at 1$ a watt, and no worry about leaving it alone and overcharging

[Privilege]

One thing that hasn't been mentioned but might be important...I assume that you have a battery charger on board and hooked up to the 110v AC. Is it a smart charger capable of multi-stage charging at different voltages. Is it a 12v charger?

[Cheechako]

Hot batteries have a short. It's an easy way to find out which one in a bank is the bad one. Charge them for a while, turn off the charger and go feel the batteries. A shorted one will be hot the rest not. I have had two batteries of less than a year old go bad from shorts over the years. It's a manufacturing defect I think.

BTW: Water heaters are usually AC powered, turning on your heater didnt effect the batteries at all.

You need to find out what type charger you have and make sure it is functioning correctly, not overcharging.

[S/V Alchemy]

Originally Posted by Cheechako

Hot batteries have a short. It's an easy way to find out which one in a bank is the bad one. Charge them for a while, turn off the charger and go feel the batteries. A shorted one will be hot the rest not. I have had two batteries of less than a year old go bad from shorts over the years. It's a manufacturing defect I think.

BTW: Water heaters are usually AC powered, turning on your heater didnt effect the batteries at all.

You need to find out what type charger you have and make sure it is functioning correctly, not overcharging.

Indeed. I read this quickly, but my impression was that we were not told what type of batteries these were (and I use the past tense for the same reasons). AGMs won't "boil over" in the usual sense, but if your charger was set for the wrong charging regimen for your battery type, or if you set it to equalization voltages without popping open the hydrocaps or replenishing the electrolyte, this sort of damage could be the result. That said, shortened internals are the most likely issue as has been said.

When you replace the batteries, make sure you know your charger settings are correct for what you are trying to do. A temperature monitor is pretty common for the better sort of charger, and can be made to work an alarm if things get overwarm.

[fatherchronica]

I had a friend once who was a tinkerer of all things and frugal to a fault. Not because he needed to, but because he could, he would get old used batteries from service stations, before the days of deposits on the cores, and hacksaw the bottoms off of them, gently remove the sediment from the between the bottoms of the lead plates, silicone the bottom of the batteries back on, fill them and charge them and use them for another year or so. Not something I would recommend on a boat, unless you were aground on a deserted island with nothing else to occupy your days. His batteries were mostly swollen looking. He had a little collection of 6 volt batteries he was repairing? and storing with his huge collection of solar panels of all sizes and brands he was going to go off the grid with one day.

[zeehag]

bulge=buy new

[a64pilot]

Swollen or bulged means nothing, in fact if you look in the Lifeline manual, it specifically addresses this.
However getting hot is definitely a bad thing, batteries can suffer from thermal runaway, again addressed in the Lifeline manual.
I know you don’t have lifelines but one AGM battery is pretty similar to another AGM battery, there are differences of course, like can you equalize etc.
If you turned on the hot water heater running it off of an inverter to draw some power out of the battery, that was a bad thing, it would if anything make the battery even hotter.
However I agree, they are toast.
What I would do is remove them from the bank and start looking for a new bank as it’s likely the rest are pretty much gone too.
Maybe look to see if golf cart batteries are a good fit for you?

[Captain Parry]

Was battery covered under warranty for a shorted cell? A friend had solar do this to a sailboat battery. Walmart replaced.

[guyrj33]

Here are the specs on the Odyssey batteries being discussed.

Product Specifications for ODYSSEY Marine Battery Model PC1800-FT

SPECIFICATIONS:
BM Part #: PC1800-FT
Voltage: 12 Volt
Capacity: 214 Ah
Type: AGM
Length: 22.75"
Width: 4.9"
Height: 12.44"
Cold Cranking Amps: 1300 CCA
Shipping Weight: 137.00Lbs
Warranty: 3 Year (Warranty Info)
Additional Specs:

1300 CCA, 1450 MCA, 1600 HCA
1800 Pulse Cranking Amps for 5 Seconds
475 Minute Reserve Capacity
3/8" Stud Terminals
3.3 mOhms Internal Resistance
80 in-lbs Torque
3800A short circuit current
Cycle life @ 77° F 400 at 100% DOD
-40° F to 140° F Temperature Range

https://www.batterymart.com/p-pc1800...SABEgLWL_D_BwE

advertised prices run from $472 to $944.
From the description I conclude these are AGM batteries.

IMO this was a pretty expensive way to build a house bank, and even then not the best choice in batteries. For a house bank of this size and $700 for 214AH battery I'd be looking at Rolls.
Financed from my personal account, I'd be buying golf cart batteries and a watering system.