How big a battery problem do I have?

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Deleted User YDKXO

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Arrived on boat in Italy 2 days ago to find service batteries completely flat. No problem I thought; it is 6 weeks since we used boat and I never leave shorepower connected whilst we are not on the boat so batteries must have been flattened by various technicians who have worked on boat in our absence. So I switched on the shorepower and went to bed. In the morning I was somewhat perturbed to see that the battery voltage as shown on the voltmeter was only around 23.5-23.7V (they are 24V batteries and normally show 25.5-26.5V under charge) and also to my surprise, I saw that the battery charger was only drawing about 20A. Normally it draws 40-60A if the batteries need charging. Also I noticed a bit of a 'bad egg' acid type odour in the boat which I didn't immediately connect with the batteries as my first thought with any smell on a boat is holding tank.
Anyway I called my local Mr Fixit who consulted an electrician who pronounced that the battery charger may be reducing it's charge to the batteries because it's temperature sensor was detecting a higher than normal temperature adjacent to the batteries. Sure enough when we disconnected the temperature sensor, the battery charger whacked straight up to 60-70A. However we also noticed that the batteries were a bit warm and it was also obvious that the bad eggs odour was coming from the batteries so we concluded that the temperature sensor was telling the truth and that the battery charger was correctly not giving the batteries full charge. We also turned the engines on and checked the output of the alternator feeding the service batteries and this was showing about 70A. So based on this evidence, I decided to change the batteries. The batteries are all sealed Energiser Commercial Premium units.
I'm currently waiting to hear whether we can get replacement batteries and then of course there will be a further delay whilst they are fitted. The problem is that we are here to move our boat to Sardinia and we should have left yesterday. So I've got 3 questions that I'm hoping the forum can answer

1) If we cannot get replacement batteries quickly, is it wise to go to sea with the engine alternators pumping 70A into batteries which are obviously knackered and overheating? What is the worst that can happen?

2) What is the odour? If the batteries are giving off hydrogen, which as I understand it is odourless, what am I smelling?

3) It is only 4 months since I bought the boat and the surveyor carried out a test on the batteries before I bought it and pronounced them to be in good order. We have used the boat 3 times since and there has been no indication that the batteries were failing. How can batteries fail so suddenly?
 
1 the risk with using the old battery bank is that out at sea you kill the batteries really dead, and have no power at all for anything. Unlikely, but the consequences are pretty grim. Possibility of batteries cracking, boiling dry, or even exploding.

2 hydrogen sulphide. Usually the product of overcharging. I believe it is flammable. Heavier than air.

3 3 months is a long time during which your battery usage and charging protocols may be responsible for failure. Bit of a long chance that a claim will succeed.


If you have to go soon, then a temporary replacement of the batteries by lorry batteries, cheap-ish and easy, may be an option. However, that does not identify the cause unless you are happy that the temp sensor is the root cause, i.e. that the ambient temp in the marina is preventing the charger form working fully. Can you direct cool air onto the batteries ? Why are they hot ? Usually it is bcs of a high load in or out.
 
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You might find that the alternator can be fitted with a temp. sensor; alternatively, fit a management device twixt alt. & batts. with a sensor.


John G
 
I had this over last year with the bow and stern thruster batteries - I put it down to old age as they were 7 years old, which I have found historically is about all I get out of a boat battery. I suspected the battery charger but engine and domestics were/are OK and voltages were correct. I have had car batteries fail in less than 9 months so possibly just bad luck on your part. If your boat has not been used much prior to you buying it, the batteries may have gone completely flat several times after which they never really recover.

As for the surveyor checking them I wouldn't put too much credence in the results unless he used a full load current tester and checked the recovery time. If he just put a voltmeter on them it won't tell you much. You may have a claim but all the surveys I have ever had have so many wiggle out clauses its probably unlikely you will be covered for what is essentially a consumable.

Replacement wise I use lorry batteries as when in the marina or anchored I use the gennie or shorepower for the aircon etc so the battery bank is never loaded up for very long. If you fit lorry type vented batteries just check your charger doesn't need some switch or setting changing for vented instead of sealed.

I wouldn't go far without putting new ones on - you never know what will happen out at sea. If you try and force charge them they will get extremely hot and may split - you don't want boiling sulphuric acid anywhere.
 
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Mike you may be lucky that only one battery in the bank is faulty and dragging down the others , if you can isolate them all and check the voltage after standing for an hour disconnected you should be able to see if its just one or two or all knackered . ( unless your mr fixit has already done this check )
As said a couple of locally sourced truck batteries may be a better temp fix to do the trip .
 
I am not sure that they failed so suddenly- are you sure no load was left across them somehow?
Still, surely if they are over discharged, that is likely to be the end of them.
Only caution I would add from experience was my charger seems to pump in more whack as needed, and as the battery wasn't charging up, continued to whack in.. to the point I opened the hatch to find some sort of gas pouring off it, the case buckling and the battery so hot I could touch it. I understood that the temp sensor isn't really for the battery itself, but for the ambient temp-- ie winter/summer. I don't know if your batteries have one of those coloured eyes, but apparently that is usually only on one plate..doesn't mean the other plates aren't knackered. You really need to put a load under each battery and see if they behave the same under load, or, if you are lucky, just one of them is cooked.
I admit that after the superheated battery incident, I've got nervous and prefer to switch a battery out than worry what is about to happen.
 
Mike
1. Yes they can fail suddenly.
2. I don't "get" the currents you quote for battery charger. Are they on the 24 or 240 volt side - you say "drawing" which implies 240v side but then you say "Normally it draws 40-60A if the batteries need charging" which makes no sense: before inefficiency, that implies 400-600 Amps of charge current, which is nuts on a 63 footer. I put 200amps (on the 24v side) into mine at max charge btw
3. No matter. I would:
-Not go to sea as is
-Do the Andy59 check and look for one bad unit
-Replace batteries - in Antibes that is a same day in stock job!
-If you must go to sea then connect the house battery leads to one of the engine batteries and use one of the engine batteries as the house batteries. I'm assuming you have 3 banks - house, port engine and stbd engine. And I'm assuming the engine batteries are fine - only the house batteries are knackered. Remember the engine batteries might only have trickle charge feed from the 240v charger but you can manage your way around that
Good luck!
 
I agree with others, unless you find one duff battery don't go to sea like this.

Six weeks is 1,008 hours so it doesn't take much current outflow to kill even a large bank with no charge.
 
I had similar issue on my saily boat domestic bank, checked each individual cell with hydrometer and found one duff cell, hoiked out offending battery, and continued with just two till replacement could be found.

Thats one of the benefits of using unsealed flooded lead acid batterys, much easier to trouble shoot...cheaper too!
 
jfm said:
Mike
1. Yes they can fail suddenly.
2. I don't "get" the currents you quote for battery charger. Are they on the 24 or 240 volt side - you say "drawing" which implies 240v side but then you say "Normally it draws 40-60A if the batteries need charging" which makes no sense: before inefficiency, that implies 400-600 Amps of charge current, which is nuts on a 63 footer. I put 200amps (on the 24v side) into mine at max charge btw
3. No matter. I would:
-Not go to sea as is
-Do the Andy59 check and look for one bad unit
-Replace batteries - in Antibes that is a same day in stock job!
-If you must go to sea then connect the house battery leads to one of the engine batteries and use one of the engine batteries as the house batteries. I'm assuming you have 3 banks - house, port engine and stbd engine. And I'm assuming the engine batteries are fine - only the house batteries are knackered. Remember the engine batteries might only have trickle charge feed from the 240v charger but you can manage your way around that
Good luck!
Click to expand...

Thanks for all replies. It seems like I made the right decision not to go to sea. With regard to the battery charge current 'draw', sorry the post was written in haste and a better word would have been 'output'. The charger ammeter is stating 40-60A so yes that has to be on the 24V side. Good news is that some replacement batteries have been found and should be fitted tonight. I decided to go ahead with changing all 6 of them rather than try to identify the failed one(s) because for sure Sod's Law dictates that another one would fail at an even more inconvenient time. Best not mention to the SWMBO how much 6 new batteries is going to cost though:eek: At least I will have some fresh service batteries which should see me through my ownership of the boat, hopefully. Yup I did think about trying to use 2 of the engine start batteries as service batteries and I probably would have done this tomorrow had I not found replacements. I'm still puzzled as to how one or more of the batteries could have seemingly failed in such a comprehensive manner between one trip and another and I hope that there isn't some electrical issue that we haven't picked up
 
good decision, skipper :)

There is a possibility that one (or more) of the batteries is connected directly to some electrical kit - e.g. burglar alarm, fire detector, bilge pump, and even with the main banks being switched OFF, a current draw is a possibility. Visual inspection for unidentifed wires, followed by a clamp ammeter ?


Hope the rest of the trip goes without kerfuffle !
 
Deleted User said:
Thanks for all replies. It seems like I made the right decision not to go to sea. With regard to the battery charge current 'draw', sorry the post was written in haste and a better word would have been 'output'. The charger ammeter is stating 40-60A so yes that has to be on the 24V side. Good news is that some replacement batteries have been found and should be fitted tonight. I decided to go ahead with changing all 6 of them rather than try to identify the failed one(s) because for sure Sod's Law dictates that another one would fail at an even more inconvenient time. Best not mention to the SWMBO how much 6 new batteries is going to cost though:eek: At least I will have some fresh service batteries which should see me through my ownership of the boat, hopefully. Yup I did think about trying to use 2 of the engine start batteries as service batteries and I probably would have done this tomorrow had I not found replacements. I'm still puzzled as to how one or more of the batteries could have seemingly failed in such a comprehensive manner between one trip and another and I hope that there isn't some electrical issue that we haven't picked up
Click to expand...

Smart move. Best to have all same type & age in a battery bank.
 
sarabande said:
There is a possibility that one (or more) of the batteries is connected directly to some electrical kit - e.g. burglar alarm, fire detector, bilge pump, and even with the main banks being switched OFF, a current draw is a possibility. Visual inspection for unidentifed wires, followed by a clamp ammeter ?
Click to expand...
True but there's no sign of water or smoke in the boat so I don't think an alarm or bilge pump has been operating. Fingers crossed for tomorrow
 
Good decision not to go to sea and can he all batts.

Have a safe trip to Sardinia, I am a week behind you but coming from Rome via Giglio and Bonifacios
 
Deleted User said:
Thanks for all replies. It seems like I made the right decision not to go to sea. With regard to the battery charge current 'draw', sorry the post was written in haste and a better word would have been 'output'. The charger ammeter is stating 40-60A so yes that has to be on the 24V side. Good news is that some replacement batteries have been found and should be fitted tonight. I decided to go ahead with changing all 6 of them rather than try to identify the failed one(s) because for sure Sod's Law dictates that another one would fail at an even more inconvenient time. Best not mention to the SWMBO how much 6 new batteries is going to cost though:eek: At least I will have some fresh service batteries which should see me through my ownership of the boat, hopefully. Yup I did think about trying to use 2 of the engine start batteries as service batteries and I probably would have done this tomorrow had I not found replacements. I'm still puzzled as to how one or more of the batteries could have seemingly failed in such a comprehensive manner between one trip and another and I hope that there isn't some electrical issue that we haven't picked up
Click to expand...


SWMBO would have far more to stay if you had a problem at sea rather than a few grand for batteries - mine would! Are you not happy leaving your battery charger on when you are not on board and keeping the batteries topped up? This covers when the various people that work on the boat are on board and leave lights on etc. I have a PowerTXT unit that tells me if I have lost the mains as I don't want to have to replace the 10 batteries I have on board in a hurry!
 
Lozzer said:
Good decision not to go to sea and can he all batts.

Have a safe trip to Sardinia, I am a week behind you but coming from Rome via Giglio and Bonifacios
Click to expand...
Keep an eye on the weather. Forecast blow through Bonifacio strait tomorrow and Monday. We've just bashed our way to Elba into a completely unforecast F5 on the nose. Brings back less than fond memories of the E Channel
 
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