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Beauvale
Beauvale

Posted: Tue Dec 09, 2014 9:03pm

Post Subject: Batteries

Hi Tony, fitted 3 110ah batteries in April 2013 on the domestic bank and at the same time fitted 2 100w solar panels. I cruise April to October and winter moor with a landline Nov to March. The batteries have been fine during 2013 and all this year upto a couple of weeks ago. The batteries do not hold their charge now. I would have thought that charging thro solar with a mppt regulator fitted and charging thro a 4 Stage battery charger now would keep the batteries in check. I have a 12v fridge running 24/7 And a webasto diesel heater on for 30 mins a day, water pump as reqd and led lights. I have checked the output terminals on the charger and get 13 v , disconnected the starter battery, turned off the fridge and diesel heater to see if that makes any difference all to no avail. Any thoughts would be greatly appreciated.

Tony-B
Tony-B

Posted: Wed Dec 10, 2014 7:52am

Post Subject: Batteries

At this time of year Solar will only make a marginal contribution and in my view is best ignored. If that 13 volts at the charger output terminals was with charger turned on (and using an accurate digital voltmeter) I am confident that the charger is faulty or just possibly set for some very exotic type of battery. It is also possible that a battery is shorting and putting such a high load on the charger its output voltage is depressed but even so just 13 volts seems too low to me. If they are open cell batteries take the fillers of and while charging check for single cells gassing more than the rest. Also check for one battery being much hotter than the others and for strange rotten egg/acidic smells. If none of these are present then suspect a faulty or incorrectly set charger. After a day on charge using a charger tolerably matched to your demands and when it has gone into float mode you should find a voltage of around 13.6 volts. It may be lower than that when you first start to charge but it will gradually climb to possibly 14.8 but at least 14.3 volts and the hold that until the charger thinks the batteries are charged Then it should drop into float voltage of around 13.5 volts. Some chargers use a technique known as adaptive charging. This can cause batteries to be undercharged. The trick here is to either turn it adaptive charging off or when they drop into float voltage turn the charger off for (say) 15 minutes and the back on again.You may have to do this several times. If this charger is in fact a combi-inverter please make sure it is set so it can not use the inverter to provide mains power when the shore supply fails when the battery charger is in use.If you do not you can end up with failed mains power and the inverter powering the battery charger - this ensures absolutely flat and probably damaged batteries. On the basis of what you say and assuming that you are using an accurate voltmeter I suspect the charger has failed but check all the other points.

Beauvale
Beauvale

Posted: Wed Dec 10, 2014 7:45pm

Post Subject: Batteries

Hi Tony, many thanks for a quick and informative reply. The 13 volts at the charger was taken with a needle type meter so I will purchase a digital type meter and check again. The batteries are Lucas cxv113 sealed maintenance free. None are hot and no smell. Regarding shorting I turned everything off and left just the 3 domestic batteries on charge ( disconnected the starter battery). I have a separate inverter and charger which is a sterling 20amp 4 stage charger, I assume new when the boat was built in 1998. The charger is set for sealed batteries at 14.4 v. I will check the voltages again with the digital meter and let you know. Thanks

Tony-B
Tony-B

Posted: Thu Dec 11, 2014 7:32am

Post Subject: Batteries

I was talking about the possibility of a cell or cells shorting in the batteries but as they are not getting hot and there is no horrible smell we can rule that out. make sure you inverter is NOT set to "top up" the shore supply when the load in the boat is greater than that which the shore supply can deliver. If it is set like that a shore power fialure will reult in the inveter using battery power to supply the charger and that causes very flat batteries. Exceptionally flat batteries might cause a 13 volt charger output but it would rise as the day on charge goes on.

Beauvale
Beauvale

Posted: Wed Dec 17, 2014 5:35am

Post Subject: Batteries

Hi Tony, checked with a digital meter and got 13.58v at the charger so that's okay, used Vaseline on the terminals and fitted a top cover. The batteries now seem to be okay. Probably a case of being over discharged and taking a while to recover. Again many thanks and seasons greetings. Terry

Tony-B
Tony-B

Posted: Wed Dec 17, 2014 6:10am

Post Subject: Batteries

It certainly sounds like it however that 13.56 will bve the float voltage which indicates the charger thinks the batteries are fully charged. Just to be sure I would turn it off at in late afternoon and back on first thing in the morning. The evening and overnight use should have discharged the batteries enough for the charger to start at 14 volts or more. It may even do it if you turn the charger off and on again. That way you can be sure the charger will deliver an absorption voltage. Cheers TB

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