Is Our Battery Bank Dead?

[unbusted67]

I am currently out cruising with my family and I am convinced our 360 Ah bank is on it's last leg but I am having a hard time convincing the owner to go for new batteries. We are in Ensenada heading South and I am worried about the safety implications if we don't get on this.

I spoke with the P/O the other day and he said the bank of batteries was 4 years old. We are seeing 12.25 amps after only expending about 15 Ah. I think that seems like we are having a hard time holding a charge. We are also unable to get enough oomph to our windlass to turn the thing. Right after we try to use the windlass the batteries are reading after having been almost fully charged before 12.15V. Whenever we use the Hydrometer on the batteries we are getting a lower end "fair" reading. We have recently equalized our house bank and have seen no improvement.

We have 4 6 volt wet cells run in series parallel and one gell cell starter battery. We have a Zantrex battery monitor.

Am I just being paranoid or does it sound like these batteries are badly diminished?

[FSMike]

I'm not a battery expert but it does sound like you have at least one weak battery. Having said that, I never operate my windlass without the engine(s) running.

[unbusted67]

When we equalized two of the batteries heated way up and boiled and two were kind of stagnant.

[forsailbyowner]

I would fully charge, then disconnect the cables and let them sit for a day. Then check the voltage of each battery to see if they're reading the same. If one has shorted it will show significantly lower voltage.

[CharlieJ]

It does sound like your bank, or a portion of it, has reached its end of life.

To confirm the fact that the bank has changed, and convince the owner to install new batteries:
1. What does the Xantrex battery monitor report for charge efficiency factor (CEF)?
2. Did you take specific gravity readings while you equalized and if so, what were the temperature compensated readings?
3. Are there any cells that are using more water than the other cells?
4. Do you have a digital voltmeter on board?
5. Check simple things like conductor integrity from the charging source to the bank; switch position; conductor termination integrity; connection of the termination to the battery; etc. to ensure that you are, in fact charging the entire bank.

Four years is about the average lifetime for a flooded lead acid golf cart battery, especially if it has remained on float charge for most of its life.

Hope this helps.
Charlie

[GeoPowers]

I think the hydrometer readings give you your answer as to the batteries' condition. If there is just one bad battery, I think you will be better off isolating it but then you are down to a 180 amphour bank since you have 6 volt batts. Make sure your starter batt is isolated (and in good condition) so you don't lose ability to use the motor. Agree w running the motor while using the windlass. Good luck!!!

[unbusted67]

Originally Posted by CharlieJ

It does sound like your bank, or a portion of it, has reached its end of life.

To confirm the fact that the bank has changed, and convince the owner to install new batteries:
1. What does the Xantrex battery monitor report for charge efficiency factor (CEF)?
2. Did you take specific gravity readings while you equalized and if so, what were the temperature compensated readings?
3. Are there any cells that are using more water than the other cells?
4. Do you have a digital voltmeter on board?
5. Check simple things like conductor integrity from the charging source to the bank; switch position; conductor termination integrity; connection of the termination to the battery; etc. to ensure that you are, in fact charging the entire bank.

Four years is about the average lifetime for a flooded lead acid golf cart battery, especially if it has remained on float charge for most of its life.

Hope this helps.
Charlie

And what should our CEF be?

[CharlieJ]

Greater than 80%

[scratcher]

had similar experence with 4x 12v batterys connected in parrallel. p/o had connected across the two centre batterys.The two outside batterys died within a year and dragged down the two centers ones.Only through this site did I learn the importance of connecting up batterys in the correct manner

[top_deck2]

Have just replaced all 6 of my 225 amp 6 V batteries. When winching the winch was having a hard time pulling up the anchor and of course the skipper couldn't understand when the batteries were still reading 12.5V. However lucky me had a mate on board who was in the know. He tested the bank under load and was able to indicate which battery was causing the prob but as we are in series and parrelled its not so easy to take just one battery out. The other indication was a slight swelling around the +Positive posts on all 6 batteries and the fact they were 4 years old. Now have my 8 new 6V 225amp Batteries intsalled and operational and am very happy. We only completed the job today!!! Our cranking battery is completely seperate from the house bank!!! Good luck hope you can convince owner to replace as this could cause real issues.