Boat Yard electrical advice questioned

[Caliber40]

All....friend of mine has battery issues on his Beneteau 46 used primarily for weekend cruising.

Batteries: 4 ea 4D wet cells

Symptom....premature death

We already know owner lets them discharge too much....have corrected this...my recommendation let batteries go no lower than 12.3V

Other Yard suggestions:
" you weekenders leave batteries on charge too long....when you come down disconnect shorepower and let the batteries run down to 50% a couple times"

I see no value in this....I see no issues with leaving batteries on full charge for as long as your hooked up to shore power. Why cycle batteries unnecessarily?

Opinions?

2nd suggestions....your battery bank is too big....
My opinion is perhaps for a weekender but it's a big boat with plenty of toys....big bank not hurting.

Opinions?

3 Rd suggestion from Yard.No need to equalize to recover batteries....if you have not routinely equalized it won't help to start now. Opinions?

[ranger58sb]

Originally Posted by Caliber40

All....friend of mine has battery issues on his Beneteau 46 used primarily for weekend cruising.

Batteries: 4 ea 4D wet cells

Symptom....premature death

We already know owner lets them discharge too much....have corrected this...my recommendation let batteries go no lower than 12.3V

Other Yard suggestions:
" you weekenders leave batteries on charge too long....when you come down disconnect shorepower and let the batteries run down to 50% a couple times"

I see no value in this....I see no issues with leaving batteries on full charge for as long as your hooked up to shore power. Why cycle batteries unnecessarily?

Opinions?

2nd suggestions....your battery bank is too big....
My opinion is perhaps for a weekender but it's a big boat with plenty of toys....big bank not hurting.

Opinions?

3 Rd suggestion from Yard.No need to equalize to recover batteries....if you have not routinely equalized it won't help to start now. Opinions?

I'm not expert... but sounds like some horsehockey in there.

Depth of discharge already addressed, good. Periodic and adequate service, too?

Bazillions of owners leave their boat on the charger always when at the dock. Assumes modern/decent charger... Maybe the boat yard is guessing the charger in questions is a 40-year-old ferro-resonant automobile charger? Or maybe they haven't heard of modern chargers yet...

Battery bank too big? Crappola.

I dunno whether equalization will help if the batteries are too far gone, but if the manufacturer supports equalization, probably can't hurt to try. Is the yard offering to sell and install new batteries?

For the really knowledgeable folks here, you might hum a few more bars about which 4Ds, installed how long ago, bank configuration, charging system (charger? solar? wind? etc) and so forth.. and whether properly/routinely serviced or not. That kind of inf might elicit even better feedback...

-Chris

[Caliber40]

Thanks Chris....good info....the owner has already given up on his batteries and is having the boat yard install a new 6V system......,"you can lead the horse to water but you cant make him drink"

[Colin A]

Equalize is worth a shot but they may be too far gone.

In general if the charger is a good one (and properly set up) keeping them on float should do more good then harm as long as water levels are maintained.

[atmartin]

Boatyards/Marinas are notorious for killing batteries. Most banks don't make it more than two years unless the owner is on top of it. I'm no electrician, but I doubt the guys taking care of this boat are either.

Common occurrences:

-Owner leaves 12v reefer and other appliances on when he leaves. Either he doesn't get the shore power connected right or a mechanic/customer with a dock cart knocks the plug loose. Batteries get a nice deep discharge before anyone realizes what happened.

-Boat get hauled for winter and batteries sit, possibly with a small load and in cold weather, for weeks before they get pulled from the boat and put in battery storage.

-No one, owner or yard, checks the water levels. After one or two of these deep discharge cycles, the top of the plates are dry.

-The battery charger get confused by one thing or another and toasts the batteries while no one is watching. Or, due to too deep a discharge (see previous), gets confused and won't come on.

Again, not an electrician, but most of the battery banks I see killed are murdered through sheer carelessness, nothing complex about it.

[Caliber40]

Thanks Colin.....good advice....pretty much all replies confirmed what I thought!

Greg

[River Cruiser]

I have 2 8D lead acid batteries. 1 start and 1 house loads. The ProMariner 60 amp charger is always while on shore power or when the generator is running. The house battery last 4 years and the start was 7 years old when I replaced it. The start was still good but I was going to Lake Michigan and didn't want any problems. I check the acid level 2 times a year and probably add a pint total to both each time. I've been buying Interstate batteries and have been getting excellent service from them, plus they deliver to the boat.