Boat battery maintenance

Batteries do self discharge when not being used. They also sulphate. So best to use a battery maintainer. The batteries may still have enough charge left if the spring to start the boat if nothing is done and batteries are left in the boat. But now you are trying to charge low batteries with the alternator.

As the batteries get more expensive it becomes more important to use a battery maintainer. At $80 a pop in Walmart not a big deal to replace a car sized marine battery. But at $200 to $300 for a large marine battery times 2 or 3 or 4 batteries a battery maintainer starts to look like a good idea.
 
BatteryMinders on all my expensive $100 plus batteries. 10 yrs out of AGM snowmobile & motorcycle batteries consistently. They get replaced due to time factor not that the will not crank.
Boat and PWC get the same treatment, if getting parked for a while or in seasonal storage they get plugged in. My vacation place mower is also on one, it doesn't get the run time the home one gets with year round use.
Basically my rule is if it doesn't have a manual recoil starter backup the battery gets maintained.
Maintainer pays for itself by doubling the battery's useful life initially, then it's free money going forward IMO.
 
BatteryMinders on all my expensive $100 plus batteries. 10 yrs out of AGM snowmobile & motorcycle batteries consistently. They get replaced due to time factor not that the will not crank.
Boat and PWC get the same treatment, if getting parked for a while or in seasonal storage they get plugged in. My vacation place mower is also on one, it doesn't get the run time the home one gets with year round use.
Basically my rule is if it doesn't have a manual recoil starter backup the battery gets maintained.
Maintainer pays for itself by doubling the battery's useful life initially, then it's free money going forward IMO.

And depending on where one stores the batteries and how expensive they are you can get the BatteryMinder that does high/low temp compensation. But more $$.
 
And depending on where one stores the batteries and how expensive they are you can get the BatteryMinder that does high/low temp compensation. But more $$.
Temp compensated ones on my batteries that are up in the ADK. That's how I've gotten 10 yrs. out of my sled batteries for years with the 100 deg. temp. swings they see over the course of a year.
 
I purchased a battery maintainer years back for my M5 to keep its battery healthy during the winter months based on a recommendation by I believe @Quattro Pete who had one from their product line. It was a PRO-LOGIX Solar unit, I believe QP has this one:

I bought this one:

My dad borrowed it and liked it so much he bought one for his Lincoln that is parked during the winter. So we use one of these to maintain the boat batteries in the off season, works very well! Has temperature compensation and a program to maintain the battery's condition.
 
It would be interesting to measure the current when the battery is fully charged. I imagine it finds some low rate to keep the battery charge consistent. Has anyone ever put a clamp on one?
 
One of the best ways to determine full charge is by the amperage accepted at absorption voltage( 14.4 to 14.7v).
On AGM's its the only way.

Whan a 100 AH capacity agm, can accept 0.5 amps or less when held at 14.4 to 14.7v, then it can be considered fully charged.

When new and healthy some of them if held at higher voltages, amps will taper to well below this level
When older some AGMS will never taper to this level, but amps will bottom out then start increasing again.
Full charge can then be considered where amps bounce off the bottom.

Flooded batteries are similar, but in general require more amperage to be held at the same voltage, instead of 0.5% of capacity it can be 2 to 3%, but really it depends on the specific battery and its health and its temperature.
Broad brush strokes here, reveal only ignorance and lack of sufficient experience.

But for most people the greeen light on a charger is an All knowing powerful god, and usually more than good enough in most applications and uses.

One cannot determine full charge via amperage accepted at float/maintenance voltages.

Each battery will be different, and will change as it ages, and change with temperature.

Generally older batteries require more and more amperage, when fully charged, to be held fully charged at float voltage.

Once this increases above the available amperage output of the maintainer, then voltage drops.

Amp clamps might not measure low currents very well.

Frequent rezeroing might be required, as might be relocating anything nearby that is magnetic.
 
Well, this weekend its time to winterize the boat, after a great summer.
For the battery, I do the following = I turn the battery switch to the "Off" position.

After 3 years I replace marine batteries, its cheap and to me, no different then replacing a battery in a flashlight, except for a boat, more important.
Since I am on a lake now, its not as big a deal and MAYBE I will wait to the 4th year but doubt it.
I used to live on Long Island NY and venture out into the ocean for hours of which could have been any number of around 6 to 8 boats I owned in my lifetime (not at the same time)
For wife and I this is our perfect lake boat, kids older now. Our lake is 41 miles long and I am back the size boat I owned when I was 17 years old. *L*
 

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Chaparral builds a nice boat. I just bought a Chaparral Signature 270. 3 batteries.

Worked on winterizing it today. Battery would not start it to winterize. Needed to jump it.
 
Chaparral builds a nice boat. I just bought a Chaparral Signature 270. 3 batteries.

Worked on winterizing it today. Battery would not start it to winterize. Needed to jump it.

Congrats! The 270 is a gorgeous cruiser. Good luck with it.
MANY years ago (decades now *L*) I had a Sea Ray 268 Sundancer. It was an awesome cruiser.
At that time I used to boat on the South Shore of Long Island. When underway I would have the battery switch set to both batteries "on" but if moored overnight in the bay I would always switch to one battery to assure I would be able to start if I ran the other one down, in case after a night of the refrigerator, lights ect wore down the battery. Also when running out into the Ocean fishing, GPS was still kind of new on the scene and I only used a compass when heading out and to get back to land.
It was awesome being out there, no land in sight and navigating back to the inlet with the compass at the same time, I felt extra safe knowing I had one extra battery backup if something went wrong while out there.
I also had a 21.5 (ish) Sea Ray midcabin before the 268 with a 2 battery set up that I did myself. Its possible the 268 had a seperate battery for the appliances, cant remember, I also installed an automatic system on the smaller boat that would connect both batteries and charge them while under way but disconnect them once the engine was off IF I only had one battery turned on they both would still charge so the second battery was always just a back up.

Fast forward to today, now on a Lake, kids grown and just this small runabout 18 ft Chaperral that I picked up for a song and a dance last year, its a 2008 and had 65 hours on it! Boat is like new being it was a lake boat not a spot of rust anyplace no the engine, looks brand new. Years later of owning more Searays I felt there quality went down and feel the Chaperalls managed to hold onto the quality better. You made a good choice for sure as far as I am concerned.
 
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Congrats! The 270 is a gorgeous cruiser. Good luck with it.
MANY years ago (decades now *L*) I had a Sea Ray 268 Sundancer. It was an awesome cruiser.
At that time I used to boat on the South Shore of Long Island. When underway I would have the battery switch set to both batteries "on" but if moored overnight in the bay I would always switch to one battery to assure I would be able to start if I ran the other one down, in case after a night of the refrigerator, lights ect wore down the battery. Also when running out into the Ocean fishing, GPS was still kind of new on the scene and I only used a compass when heading out and to get back to land.
It was awesome being out there, no land in sight and navigating back to the inlet with the compass at the same time, I felt extra safe knowing I had one extra battery backup if something went wrong while out there.
I also had a 21.5 (ish) Sea Ray midcabin before the 268 with a 2 battery set up that I did myself. Its possible the 268 had a seperate battery for the appliances, cant remember, I also installed an automatic system on the smaller boat that would connect both batteries and charge them while under way but disconnect them once the engine was off IF I only had one battery turned on they both would still charge so the second battery was always just a back up.

Fast forward to today, now on a Lake, kids grown and just this small runabout 18 ft Chaperral that I picked up for a song and a dance last year, its a 2008 and had 65 hours on it! Boat is like new being it was a lake boat not a spot of rust anyplace no the engine, looks brand new. Years later of owning more Searays I felt there quality went down and feel the Chaperalls managed to hold onto the quality better. You made a good choice for sure as far as I am concerned.

One thing this boat has that most other Chaparral Signature 270 do not have is a bow thruster. Its hard docking with a single engine, backing into the slip with current and wind pushing you around. And it has A/C. Something else to winterize. And a Volvo Penta duoprop. Infinitely more expensive to repair than the Mercruiser Alpha drive in my old boat.
 
Nice feature with a bow thruster, AC too, all the way up there in the upstate, guess things progressed over time that a cruiser like that needs to have the AC for sale and resale value.
Yes, you defiantly have more of a maintenance schedule and costly unless you do it yourself. I have always done my own maintenance, including pulling those Merc outdrives and greasing up the splines, u joints in some cases, yup, also winterizing the fresh water system.hot water heater... oil changes ect. Ran and installed the electronics, used to love all that stuff. Never keep a boat long enough that an engine or outdrive needed a rebuild or any kind of major maintenance.
Im at the point in my life of competing interests here in SC, the other is my Harley... :eek:) also at a point in my life of I guess for lack of better words, limiting my spending. I LOVE lake boating on Lake Murray SC... boats stay in pristine condition in the fresh water, been here 15 years now and now I do miss, at times, the salt water, great South Bay and ocean...
Im assuming you run in fresh water so things should last a lot longer then then did in the salt of the bays and oceans.
My Nephew on Long Island has a Sundancer 280, early=mid 2000's ? I dont remember, had a lot of issues with the engines, 2-V6s ... I think by now both had to be torn apart and repaired/rebuilt. With these engines now have CATS on them, sensors ect to limit pollution, he always had issues every summer with one engine or the other, sensors issues, over heat issues, I think maybe this in the first year in a long time he hasn't had a major issue. I think your good with 1 engine *L* my brother used to have 2 as well on another SR, same deal, 2 engines, twice as maybe problems!

If your income is unlimited and for many people it is, then none of this stuff matters, I wasnt in that class ... *LOL*
 
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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.

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When talking about batteries, we must also consider climate. British Columbia cool temperatures are much easier on batteries then USA South Carolina, Texas where it is a boiling hot for months in the summer, also other moderate to warm areas like Florida.

I do think what you do is sound advice for those wishing to try to extend a battery as long as possible. I think what you do is FAR superior then leaving a battery "maintainer" constantly on the battery which if they aren't working right will keep a battery in a constant warm state and batteries hate heat.
 
Nice feature with a bow thruster, AC too, all the way up there in the upstate, guess things progressed over time that a cruiser like that needs to have the AC for sale and resale value.
Yes, you defiantly have more of a maintenance schedule and costly unless you do it yourself. I have always done my own maintenance, including pulling those Merc outdrives and greasing up the splines, u joints in some cases, yup, also winterizing the fresh water system.hot water heater... oil changes ect. Ran and installed the electronics, used to love all that stuff. Never keep a boat long enough that an engine or outdrive needed a rebuild or any kind of major maintenance.
Im at the point in my life of competing interests here in SC, the other is my Harley... :eek:) also at a point in my life of I guess for lack of better words, limiting my spending. I LOVE lake boating on Lake Murray SC... boats stay in pristine condition in the fresh water, been here 15 years now and now I do miss, at times, the salt water, great South Bay and ocean...
Im assuming you run in fresh water so things should last a lot longer then then did in the salt of the bays and oceans.
My Nephew on Long Island has a Sundancer 280, early=mid 2000's ? I dont remember, had a lot of issues with the engines, 2-V6s ... I think by now both had to be torn apart and repaired/rebuilt. With these engines now have CATS on them, sensors ect to limit pollution, he always had issues every summer with one engine or the other, sensors issues, over heat issues, I think maybe this in the first year in a long time he hasn't had a major issue. I think your good with 1 engine *L* my brother used to have 2 as well on another SR, same deal, 2 engines, twice as maybe problems!

If your income is unlimited and for many people it is, then none of this stuff matters, I wasnt in that class ... *LOL*

I am moving to Delaware by the spring and will be boating in the salt water Delaware Bay. Our retirement home is around the Rehoboth Beach area. Only ocean or bay in that area. Salt water will be a challenge. People get A/C to keep humidity down in the cabin.

My old boat had a Mercruiser Alpha 1. This boat has a Volvo Penta duoprop. Twice as heavy to remove and probably 5X as expensive to replace. But a better drive in several ways.
 
One big plus, engine mounted seawater intake pump instead of the Merc outdrive pick up pump. Yes, Im well aware of the engines and outdrives of the manufacturers. Dont pay as much attention but been reading for decades now, including when the duo prop first came out... *L* that was a long time ago.
 
One big plus, engine mounted seawater intake pump instead of the Merc outdrive pick up pump. Yes, Im well aware of the engines and outdrives of the manufacturers. Dont pay as much attention but been reading for decades now, including when the duo prop first came out... *L* that was a long time ago.

Yes, the raw water pump is a 5 or 10 minute job now. And MPI is a plus. Lots of emissions stuff. And a few hundred $$ to get a boat version of a OBDII reader.
 
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

Just a quick update. After storing my boat last Friday, I pulled the larger than normal dual purpose starting/deep cycle battery out and put it on charge with the Noco I mentioned above. With 3 different settings, 12V wet, AGM and Lithium settings, I put it on the proper (12V wet) and let it be. This battery was getting down in the juice dept after sitting for almost 6+ weeks but after approx 12-18 hrs of charging, it was brought back to life and a full charge was achieved. I was curious on the 4 lights sequence but I learned once the first 3 lights go out and it is just a steady/flashing green, it means it is fully charged and just on the maintain mode.
One of my prior deep cycle batteries, either boat or trailer, would not go to green only, but thinking back now, I may have not left it plugged in long enough? Not saying this is the best battery charger out there, but compared to my previous Battery Tender, this one, imo, is leaps and bounds above it. Real happy with it so far. (y)
 
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