Charging system Question..

belliswood

Member
Nov 21, 2011
320
Colonial Beach, VA
Boat Info
1996 370 SUNDANCER
NAME: DAWG HAUS 3
Engines
7.4 EFI 454
V-DRIVES
I own a 1996 370 Sundancer. I replaced all the batteries 2016 however about half way thru this season my house batteries(2) (Starbard) would not charge up when on shore power. they would get some charge when out cruising but still not enough to start the engine. My house 12 volt works when hooked to shore power and my Port Battery works fine. Is it an issue with the charging system or have the batteries been discharged to low to recharge? The Batteries are Duracell 31 group Deep Cycle.

Thanks
 
Have you checked the water level in the batteries. If they are too low on water they will not accept a charge.
 
The fact that they don't recharge on either shore power or the alternator points to a connection or battery problem. I would pull them and have them tested.
 
Deep cycles are really not recommended for a starting battery ,I would have a dedicated starting battery and a dedicated house battery system.
Check the water in the batteries and check the connections.
Have the alt checked for proper operation
 
Id start with a testing them with a simple $20 DVOM at rest, with engine running and with shore charger (battery charger) plugged up. Much easier then pulling batteries and will tell you A LOT.
 
Pretty easy to figure out with a volt meter with the batteries in the boat.

How old is your charger?

Does it have some status lights or a digital display telling what it's doing when on shore power?
 
I don't think 2 would go bad at once, so check connections, water, etc. Get a volt meter, check at battery terminals-around 12.2-12.5 Volts engine not running, 13.5-13.8 engine running. Clean the battery terminals.
 
Thank you everyone that responded. Brought the batteries home and put on battery charger. not charging up. both were house batteries so I guess there must have been a power outage at the marina that caused the batteries to be ran down so low they won't charge up again. will be buying new ones come spring..
 
There is something wrong with either the batteries or your charging system. There's no way new batteries should go dead in less than a year's time. In any event, bring the batteries back to where you purchased them and get a prorate on the new batteries.
 
Many modern chargers will refuse to charge a battery that has run down too far - if you have a old "dumb" charger, it may breathe some life back into them.

By being run down for an extended period, and too far for the on board charger to charge, the have been permanently damaged. But as they are house, not starting batteries, you may be able to get enough life back into them to go another season or two....
 
I kind of agree with Mick. I would not trust a charger "not charging up" unless I was watching it real-time on a digital diagnostic volt meter.

Even if the batteries are toast, still leaves the question as to why. Dont install new batteries and think its all good. Still need to test the alternator output and charger output.
 
I have a 96 400DB and had to replace the charger. It fried a bank of batteries within one year. I replaced it when I put in new batteries and the next day one was very hot to the touch. I would not wait for issues with the charger to get worse. Would suggest eliminating an original charger as soon as possible on that year boat, if you haven't already.
 
Had a similar problem with a 97 370 and it was the charger. Called ProMariner and they gave me a reduced rate on a replacement, easy job too.
 

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