House electrical issue - just old batteries?

[camdunning]

Hi all, I'm having an electrical issue that I'm trying to sort out and could use a sanity check. My boat has five batteries total, 2 are wired up to be the 'house' bank, two are banked as starter batteries for the main engines, and the last one starts the generator. There's no selector switch, and the bank is charged by a 5/5/5 15 amp charger. I am plugged in to shore power full time, so the charger is always going.

Lately if we run lights on the house system for more than maybe an hour, they start dimming, and will dim drastically if the water pump kicks on. Evidently this morning the lights and the water pump stopped working entirely (I'm at school but got some exasperated messages from my girlfriend). Is this most likely due to the batteries just being at the end of their useful life? I believe they're between 2 and 4 years old. Since we're permanently on shore power though, should the battery charger be keeping up with the power use and not drawing the batteries down at all?

The battery charger shows that the batteries are charged full right now (even though they're not), so I'm also going to check for corrosion on the terminals and/or blown fuses when I get home, but would appreciate any tips you all might have.

Thanks for the help!

 

[O C Diver]

Some pics would be useful. Are the batteries open lead acid? Have you added water to the cells?

Ted

 

[camdunning]

Thanks for the response. I'm not sure but would assume they're lead acid, I'll take some pictures when I get home tonight.

Haven't added any water, I'm new to boating and just starting to figure out how much stuff I know nothing about, but need to start learning.

 

[Steve]

Try to buy beg or borrow a copy of latest edition of this book. It will be a valuable reference source.

Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair, and Improve Your Boat's Essential Systems: Nigel Calder: 9780071432382: Amazon.com: Books

Good luck

 

[tpbrady]

I second the Nigel Calder book. I got it on Kindle and have copies on my IPhone, IPad, and laptop. A great reference with a good explanation of systems. When you are on the way home tonight pick up a volt meter if you don't already have one.

Tom

 

[Wxx3]

Instead is using to learn 10 years of electrical theory in a day, I'd suggest your time and money works be far better spent trying to find a fellow boater who knows electrics or can recommend someone to help you.

 

[FF]

5 amps , even 24 hours is only 100a at best.

Sounds like you need a 20-40A charger ,OR a reduction in loads to 100AH per day.

Yes it also sounds like the constant undercharged state has eaten the house batts.

 

[DavidM]

I agree with Fred's assessment. A 5 amp charger may not keep up with the lights if they are incandescent types.

Replace the two house batteries and replace the charger with a 20 amp, 3 output unit as Fred suggests.

You have a perfect opportunity to replace the two with a pair of 6V golf cart batteries wired in series. These will probably add 50% amp hour capacity in almost the same space. They are taller however. GC batteries are true deep cycle house type batteries, whereas many Group 27s (which is what you may have) are not.

David

 

[dimer2]

All good advice. Batteries need water to work. In the meantime, you have unlimited shore power...use it. Use lamps plugged into the 110V sockets and remove as much load from the 12v as possible. The largest power user is probably your girlfriend but removing her may cause other problems not covered in the books mentioned above.

 

[FlyWright]

All good advice. Batteries need water to work.

It's important to use DISTILLED water to your batteries, never tap water.

 

[dimer2]

It's important to use DISTILLED water to your batteries, never tap water.

Thanks Al, I should have been more specific.

 

[camdunning]

Thanks all, vey helpful tips all around. I'll check the water levels today, and if that fails, then I'll swap out for some new batteries and a larger charger.

Drawing more amps than the charger can put back in makes sense - we use 110v for most things (fridge, floor heater, anything in an outlet) but the ceiling lights and the freshwater pump are both tied to the 12v system. The main room has four lights, and there are more in the kitchen, bedroom, bathroom so I guess this draws a fair amount of amps in total. Sounds like we need an upgrade to our system.

Dimer2 - you're right, the girlfriend is definitely the largest power user. At least of my power levels.

 

[BruceK]

Cam, a couple of thoughts:
Replace the 12v bulbs with LEDs. My 5 house LEDS use less than one conventional.
My guess is batts. Do a simple voltage test. Also, a hydrometer tester is cheap, available at chandlers,easier than it sounds. One sick cell=battery cactus.
Think about adding solar for maintenance. First cost is the last, batteries will be charged and maintained.
If flooded wet cell batts (where you unscrew caps to top up), check fluids say monthly until you establish frequency needed.

 

[koliver]

I don't know how anyone on this board could survive with only a 20 amp charger, and you only have 15. Get real. You need a 100 amp charger on your shore power circuit. Get one that is part of an inverter, with a "smart" 3 step charging protocol and you won't regret it.
Then look at your alternator. Again you need at least 100 amps and a "smart" regulator. Again you won't regret it.
Then you can relax about what the girlfriend does.

 

[FF]

My suggestion for a 20A+ charger is for the HOUSE batt set , not split up between other users.

The 15 can stay charging batts that have no load except their internal death.

 

[High Wire]

No water for years on charge 100%? I'll be amazed if those batts do not have at least one dry cell each.

 

[camdunning]

Just thought I would post a quick update to this. I ended up replacing mostly all of the cabin lights with LEDs, and haven't haven't had an issue since (thanks for the suggestion BruceK). My batteries will probably need replacing in the near future, but this seems to have bought me some extra time and will hopefully prevent the issue from repeating itself with the next set of batteries.

Upgrading the battery charger probably would have worked as well, but that was outside my current budget. Thanks for all of the suggestions, my home situation and the girlfriend's mental well-being seem to be much improved.

 

[Alaskan Sea-Duction]

Instead is using to learn 10 years of electrical theory in a day, I'd suggest your time and money works be far better spent trying to find a fellow boater who knows electrics or can recommend someone to help you.

Good advice here. You should also check your water levels every 30-days with being on a charger full time. Sounds like you have boiled the batteries and need new ones, but I am just guessing.

BTW Welcome aboard!

 

[dhmeissner]

I did this...boiled the batteries. Had an old 40a dumb charger connected for weeks on end, I would check the electrolyte level and add water but they still died an early death. Am installing a new Magnum 70a inverter/charger at the moment. My new batteries will be much happier.