Hot Batteries

[richardbayle]

I'm sure this has been covered before, most things have but I have an issue.

Boat is in the Caribbean, and has been resting in the marina during the hurricane season, now getting it ready again. have had the battery charger on for a while now, about 4 months, never had an issue before and I leave it on whenever the boat is at her pontoon. Went down today, odd smell in the cabin and two of my house batteries very hot.

I have 3 house and one engine, one batt is stone cold as per normal, one hot and the other very hot, I mean very hot! Clearly i have a problem.

Assuming overcharging, I have switched off battery charger, and am contemplating disconnecting the batts.

Any views or comments would be very helpful.

 

[matthewriches]

Disconnect and maybe change one at a time under supervision. Monitor what they do and then act on that info.

 

[richardbayle]

Thanks I'll do exactly that. Appreciate your help

 

[matthewriches]

If your local friendly marina workshop or boatyard would run their test equipment over them, then all the better for the price of a beer.

I found a customer had a bank of 4 batteries, all very old. They were linked in a parallel and the charger was linked onto the + and - of the first battery. That was significantly warmer on a thermal imaging camera than the last of the bank.

So in short, ensure the + is on 1 end of the bank and the - is on the opposite end of the bank.

Thanks I'll do exactly that. Appreciate your help

 

[richardbayle]

Boatyard? Workshop? Hmm not in this marina but we do have many talented friendly locals. Tomorrow morning I'll see if any are around. :

 

[William_H]

I would suggest that a battery gets hot with excessive charge current. This can happen if one cell dies so voltage is perpetually low so charge current high. Th9is situation exacerbated when batteries are in parallel Alternatively charger may have gone cactus. Both options of great concern. ol'will

 

[jordanbasset]

I had the same situation, after much testing changed the one that got hot (it didn't hold a charge). Within a week or so the other battery started also to got hot. Replaced that one as well, so now have two new batteries, 18 months later still both okay (as you should expect)
I was worried, perhaps unduly, but it did get very hot and I did not fancy an exploding battery on the boat!

 

[Pasarell]

Almost certainly the very hot batteries have failed cells that are shorting. Smell is probably hydrogen sulphide (rotten eggs) given off by the battery. They will not accept a charge so the charger keeps trying to pump power into them and they get very hot - and potentially dangerous. Time to bite the bullet and replace I'm afraid.

Disconnect from charger and get them out of the boat as soon as possible but be careful if they have distorted as acid may leak, or have already leaked, so use good PPE.

 

[Irish Rover]

I had a similar problem while cruising in the summer http://www.ybw.com/forums/showthread.php?504251-Advice-needed-Leros-faulty-battery
4 of my 6 house batteries failed one after the other. They were all 5 years old so in the end I replaced all 6 plus the 2 starter batteries. All fine afterwards.

 

[duncan99210]

Almost certainly the very hot batteries have failed cells that are shorting. Smell is probably hydrogen sulphide (rotten eggs) given off by the battery. They will not accept a charge so the charger keeps trying to pump power into them and they get very hot - and potentially dangerous. Time to bite the bullet and replace I'm afraid.

Disconnect from charger and get them out of the boat as soon as possible but be careful if they have distorted as acid may leak, or have already leaked, so use good PPE.

+1 Hot batteries are toast.... The chance of reviving them are low, they won’t last much longer even if you did manage to get them to accept and hold a charge. Get rid and replace. We had 2 out of 5 get very hot this year; removed them as soon as I identified them, took them out of the circuit and replaced them once we got somewhere we could buy new ones.

 

[Heckler]

I'm sure this has been covered before, most things have but I have an issue.

Boat is in the Caribbean, and has been resting in the marina during the hurricane season, now getting it ready again. have had the battery charger on for a while now, about 4 months, never had an issue before and I leave it on whenever the boat is at her pontoon. Went down today, odd smell in the cabin and two of my house batteries very hot.

I have 3 house and one engine, one batt is stone cold as per normal, one hot and the other very hot, I mean very hot! Clearly i have a problem.

Assuming overcharging, I have switched off battery charger, and am contemplating disconnecting the batts.

Any views or comments would be very helpful.

They are knacked, change them! The cold one will soldier on for another couple of months then that will go as well! Technically speaking they get hot because they have "boiled" off water vapour, (even so called sealed leasure have little vents) they then cant charge fully, the charger thinks they are flat, puts more to them, they boil off more and it is a vicious circle. Dont ask how I know and two other friends as well!
Discconnect the two hot ones as an emergency measure and just run on the cold one till you can get some more.

 

[TQA]

They are knacked, change them! The cold one will soldier on for another couple of months then that will go as well! Technically speaking they get hot because they have "boiled" off water vapour, (even so called sealed leasure have little vents) they then cant charge fully, the charger thinks they are flat, puts more to them, they boil off more and it is a vicious circle. Dont ask how I know and two other friends as well!
Discconnect the two hot ones as an emergency measure and just run on the cold one till you can get some more.

+ 1

Also if you take them off charge and disconnect them for a day or so a simple check with a voltmeter almost always identifies the ones that have failed. They will have substantially lower voltages usually around 10 volts. Ideally you should have a modest load on them when you check the voltage say a searchlight.

 

[richardbayle]

Thank you all for your helpful comments.
I discnnecetd the batts last night and returned this morning to check. Batts have not leaked and the two hot ones are still warm. Agree I have to bite the bullet and buy 3 more, made the mistake of only replacing two once before, big error.
Anyway, good to have my own theory confirmed off to the chandlers in the morning, suspect I'll be told, don't have them in stock, have to order them hey ho, the joys of living in the Caribbean! That's not a complaint, just a comment.
Beautiful day here by the way,.

 

[sailorman]

Thank you all for your helpful comments.
I discnnecetd the batts last night and returned this morning to check. Batts have not leaked and the two hot ones are still warm. Agree I have to bite the bullet and buy 3 more, made the mistake of only replacing two once before, big error.
Anyway, good to have my own theory confirmed off to the chandlers in the morning, suspect I'll be told, don't have them in stock, have to order them hey ho, the joys of living in the Caribbean! That's not a complaint, just a comment.
Beautiful day here by the way,.

I would then reconsider my charging regime, connect a solar or wind & leave the mains charger off when unattended :encouragement:

 

[richardbayle]

I would then reconsider my charging regime, connect a solar or wind & leave the mains charger off when unattended :encouragement:

OK, understood altho' it has worked OK for the last 4 years. Oddly enough, apart from the odd hurricane, (Maria was a real ball breaker for us, no real mention in the press tho' maybe because we recovered pretty quick,) in the down season we don't get much sustained wind or indeed extended days of sunshine down here at the bottom of Guadeloupe. Get a lot of rain! Now if I could invent a battery charger that worked off rain, make a fortune

 

[PaulRainbow]

I would then reconsider my charging regime, connect a solar or wind & leave the mains charger off when unattended :encouragement:

Why ?

 

[ghostlymoron]

How old are the batteries?

 

[richardbayle]

3 years

 

[ghostlymoron]

3 yrs is not long for a house or starter battery. Do they have a warranty?

 

[Norman_E]

Why ?

The reason is that if you leave a powerful mains charger connected when you leave the boat it can easily overheat a failing battery. Such a battery might distort and bulge, or even split leaking out its remaining acid. A low wattage solar system giving enough charge to maintain good batteries will not have enough power to boil up bad ones, so it is safe. I have 100 watts worth of solar panels, which is enough to maintain four 105AH batteries.