Boat battery maintenance

S

Snagglefoot

Joined
Dec 31, 2017
Messages
15,326
Location
SE British Columbia, Canada
For those of you who will be putting the boat away for the fall, don’t forget to check the electrolyte of your battery (assuming you have a standard maintenance type battery) The summer here was really hot and I found the electrolyte level was quite low but sill above the plates. I topped it up with distilled water and one of those battery bulbs and then fully charged it. I usually bring it inside some time in September than top the charge a few times over the winter. Winter stuff already?:cry:
 
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Get yourself a small Battery Tender (you don't need a high capacity for long term storage) plug it in and forget it until needed. Should be able to find one for about $25.00.
 
Good point to check electrolyte, though I dont know that the need to do so is different on a boat than a vehicle. If you can check and top off, do so.

I agree its smart to fully top up the battery before putting it away. After top-up, disconnect them so any parasitic loads dont draw them down. Better yet would be to keep a maintainer on them, either in the boat or out.
 
alarmguy said:
Agree, Check battery level, disconnect battery, store in cool place. No tender ever for me.
Click to expand...
What is interesting is T have a small tractor that the battery would last 3 years until used a tender and then the battery lasted 6 years before replacement.
 
I'm in the ......insure a true full charge is attained, then disconnect completely for winter, camp.

I'd only use a maintainer if there was a known parasitic draw on the battery, below that which the maintainer could offset, or if I knew the battery had a high rate of self discharge, which many less than healthy batteries do, which only gets worse faster when they spend more time less than fully charged.

marinehowto.com

Winter Battery Storage & Self Discharge Characteristics - Marine How To

December 11, 2012 After having a discussion with one of my customers, about leaving his battery charger running on-board all winter, a practice I am certainly not a huge fan of, and one his boat yard specifically prohibits, I decided to venture into this article.
marinehowto.com

Electrolyte 'just' above the plates is when the electrolyte is strongest, and chews up the plates the quickest. Not best for storage, but it is best for apparent performance judged by voltage retention under load.

I can tell when my flooded batteries are needing water soon as they seem to be performing better than they should in the voltage retaining department., and once filled to the maximum level, 1/8 inch below the little hanging arms in the cells, they perform worst in this regard but it is of no consequence, compared to when the plates do get exposed from lack of watering in time which can be a death knell depending on how low it got and how long plates were exposed..

When people notice their battery is not performing well, and then they see low water and add more, almost always the battery is replaced soon after as the diluted electrolyte on the sulfated battery makes performance even worse.

Maintenance charger's are not for fully charging a depleted battery, and ideal float voltage depends on the specific battery and its specific temperature.
 
Rygrego said:
You will never know how long your batteries could have lasted.
Click to expand...
Yeah, but that goes either way. Tenders can also cause battery failures.
Batteries hate heat, it kills them, an improperly operating tender is far worse then no tender.
But, again, Im just replying to your "how long batteries could have lasted" statement. No one ever knows how long.

For me, I always followed Mercruisers recommendation. Disconnect battery and store in a cool place.
3 years of a boat battery and I replace it. To me replacing a boat battery (or batteries) is no different then replacing my flashlight batteries, I want a new fresh battery in there every three years, batteries cost pennies compared to the cost of operating a boat and heck in some cases depending on what boat I had cost less then a tank of gas. *L*
Also having a fresh battery reduces stress on the charging system.

But again, as insurance, having a new fresh battery (or batteries) is always worth it to me, rather then see how long I can get one to last or not as it is to critical for safety reasons and/or one can always go to dual batteries if they dont have them.
Now that boat on a lake instead of the ocean (which was most of my life) I am not as concerned but will still replace every 3 years and only have one on this boat and wont bother going to 2 batteries.

I dont trust tenders and I do not believe all the hype about them and would love to see an actual multi year study which you never will.

Again, its what I do and I am in no way saying for someone who wants a tender is wrong, we do what works for us.
 
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I'm pretty happy with the setup I use. I have a marine battery for my trolling motor, 2 lawn tractor batteries, and a motorcycle battery. I have a 1.5 amp battery maintainer and rotate it amongst the batteries throughout the winter. It has a float charge so it will not overcharge any given battery if I forget it for a day or two. The marine battery is 7 years old and still going strong. I use the cheap Walmart batteries for my lawn tractors and one is 3 or 4 years old (and going strong) and the other is newer as I got the tractor with a dead battery. As for the motorcycle, I got 3 years out of the cheap Walmart battery I purchased for it. It was still working, but I could tell it was starting to get weak. The biggest issue with it is that the motorcycle sometimes goes unused for weeks at a time and I don't use the maintainer on it during this time.
 
I got 10 years out of 2 Optima blue top deep cycle batteries. I am a firm believer in running a maintainer all the time during storage. I do this with my Corvette, boat, riding lawn mower, mini bike battery, and even put a tender on my Ford F-150 which is a 2014 and still has the original battery. I have several tenders and like the CTEK model the best and second would be the Battery Tender Plus and third would be the little $25 battery tender. You can also buy Harbor Freight low dollar maintainers for about $5.00 each and they will maintain a charge as long as your battery starts out fully charged. Tenders are cheap insurance and practically guarantee more years of service out of your batterys in my opinion.
 
I used to get 10 years out of optimas, not anymore.

Running a boat shop for 20 years and owning two boats I took care of clients and my own batteries.

Here's my charger preferences.

Optimate 6 (or 6+) - handles everything from 3AH to 240AH bank
Ctek -7002/ 2500 for big jobs.
Battery tender
 
JHZR2 said:
Good point to check electrolyte, though I dont know that the need to do so is different on a boat than a vehicle. If you can check and top off, do so.

I agree its smart to fully top up the battery before putting it away. After top-up, disconnect them so any parasitic loads dont draw them down. Better yet would be to keep a maintainer on them, either in the boat or out.
Click to expand...

I would not suggest a Battery Tender in the boat if the battery is in the engine bay. Nothing should go in the engine bay that is not designed to used in an area where there might be gas fumes.
 
Donald said:
I would not suggest a Battery Tender in the boat if the battery is in the engine bay. Nothing should go in the engine bay that is not designed to used in an area where there might be gas fumes.
Click to expand...

The tender electronics need not be there.

We mounted the chargers far from the batteries in my FILs boat. No issues.
 
I just purchased a Noco genius 2 a couple/few weeks ago as my small Battery Tender went caput. I am currently charging my Interstate deep cycle battery prior to storage and I must say, I really like this little unit. It has a lot more features and can also do a lot more than what a typical battery Tender can do. https://no.co/genius2
 
alarmguy said:
Agree, Check battery level, disconnect battery, store in cool place. No tender ever for me.
Click to expand...
This ^^ place where I kept my boat pulled the power after a tender started a fire ...
I have used a Perko switch for years and batteries stay strong ...
 
Just pulled the battery out for the winter. I store it in my heated garage and charge it twice during the winter, once at Christmas and once in February. I just finished the fourth summer on it.

59DCDD4C-531B-4C2B-BEB4-83A8999442EC.jpeg
 
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