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steing
steing

Posted: Mon Dec 19, 2011 5:17pm

Post Subject: Battery not holding charge

Hello, We left our boat in a marina for 15 days whilst on holiday, it was plugged into shorepower to maintain fridge/small icebox freezer. It is a 12V. On return marina had accidently unplugged shorepower, defrosting the whole contents of freezer. (Amount of days ? 1 - 14 days ).Only bilge pump also was taking a charge. Our problem now is that the battery bank is holding no charge when unplugged from shorepower. Engineer checked voltage (whilst still plugged in ! ) and said charge is there,about 14V, checked for loose connections - ok. When we tested again, battery was down to 11.9 in 1hr 45 mins. It is a new boat of 5 mths old. We had no problem before this, until the marina fully discharged the battery,what can be the problem, do all the batteries need replacing. ? Stein

Tony-B
Tony-B

Posted: Mon Dec 19, 2011 5:39pm

Post Subject: Battery not holding charge

I note that you do not say how long you have had it on shore-power trying to recharge it or are you just using the engine alternator? I also not the you say "battery" singular and then talk about "all the batteries" without specifying the bank size. If the batteries are drawing a high current from the charger or alternator then that 14 volts could be fine, but if they had been on charge for a number of hours it looks a bit low to me - unless the charger thinks the batteries are fully charged and has gone into float mode. You need to check the manual for the charger (in the RCD pack/ manual) to see what the voltages are for the various stages of charge and to make sure the charger is not set for a battery type that demands a lower than "normal" charging voltage. Until you can confirm the charger's voltage setting is correct for your battery type, the charger output, and the time it has been left connected I can not hope to give a sensible opinion about the batteries. Ideally you would take one battery out of the bank at a time and fully charge it. Then leave to stand for at least 24 hours. it should still return a volatge of between 12.7 and 12.8 volts. If it does not the that battery is faulty. Only after that can we make a decision about the whole bank. Ordinary "leisure" wet open cell batteries do not take kindly to full discharge so you may well have ruined the bank. Let this be a lesson to other boaters. This is the second time this month that leaving an inverter 12 v supply turned on while away from the boat has resulted in fully discharged batteries when the shoreline trips off. If you can not supply mains to the boat without having the 12v supply connected to the inverter is is time to modify the wiring so you can bypass the inverter and feed shore-power straight to the boat's mains circuit. Tony Brooks

steing
steing

Posted: Mon Dec 19, 2011 6:23pm

Post Subject: Battery not holding charge

Thank You so much for your quick reply, firstly as new boaters we thought we were doing right thing, we left our boat in the safe hands of a marina to keep shorepower to the fridge, the marina in error ( not tripped out ) unplugged and moved our boat whilst carrying out marina maintainance, and forgot ! to plug us back in, !!this could have been unplugged for anything between 1 - 14 days,likely the higher, it is not known when they re-connected us. We have been back into the marina for the last 3 days, on shorepower, only today when preparing to leave, was the problem evident. We have 3 x domestic and 1 starter all at 110 amp wet cell. No previous problem with batteries/inverter, when hooked up before. The contents of freezer never refroze. So if the batteries were completely discharged ( dead ) will they all need replacing, inverter is working/set correctly. Hope you can help us with this as we are continuous cruisers, and was hoping to be on our way tomoro. Thanks again Stein

Tony-B
Tony-B

Posted: Mon Dec 19, 2011 7:12pm

Post Subject: Battery not holding charge

After 5 months of CC-ing there is every chance your batteries were already suffering reduced capacity due to sulphation because it is very doubtful that you run your engine for long enough to near fully recharge them - think 12 hours plus per day. Without doing the test I suggested I would think that the full discharge was the last straw so perhaps a new set of batteries is the best way to go. However you must consider them consumables and expect to replace them every year or so because it is all but impossible to fully charge them whilst CC-ing. Wet open cell batteries costing between £80 ans £100 each will probably be the most cost effective for your type of use. You are likely to destroy expensive batteries as fast as cheaper ones. Being open cell you can also top them up and periodically test them with a hydrometer (notes on how on the TB-Training.co.uk website). Tony Brooks

steing
steing

Posted: Mon Dec 19, 2011 8:03pm

Post Subject: Battery not holding charge

Many Thanks again, we take on board your comments, we are careful cc on battery usage, if we have not cruised enough in day, we always top up from engine running at evening, though we know this won't be enough to FULLY charge, we also top up/ maintain with battery water using correct filler bottle. As up until we was in marina, we were happy with battery output/performance, I do believe we would have had a longer life out of them, and expenditure would not be necessary now, it is very disappointing, when WE did nothing wrong and paid for a mooring with services. We would not be in this situation if marina had not fully discharged them. I hope we can get a satisfactory outcome tomoro when we see them. You have been very helpful, Thank You so much. S

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