Battery Maintainer for Boat In Storage

Electrical and electronic topics for small boats
Jefecinco
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Battery Maintainer for Boat In Storage

Postby Jefecinco » Wed May 29, 2019 9:30 am

We seldom use our 1981 Sport 13 so it spends most of it's life in our garage. I recently attempted to charge the 13 year old battery but it would not accept a charge. I've ordered a Group 24 AGM to replace it.

I would like to buy a battery maintainer/tender to leave connected to the new battery between uses of the boat. I would wall mount the maintainer next to a wall outlet and use clips to attach it to the battery. The battery is East Penn/Deka manufactured West Marine branded. The charging recommendations are float 13.5v, bulk 14.4 - 14.6v.

Searches for a good mauntainer via Google have resulted in dozens of advertisements and fake rating sites and no useful information.

I would appreciate recommendations on a make and model of well regarded maintainers.
Butch

jimh
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Re: Battery Maintainer for Boat In Storage

Postby jimh » Wed May 29, 2019 11:12 am

BUTCH--for many years I have used a precision float charger to maintain the 12-Volt 70-Ampere-hour AGM battery I use on my work bench as a power source. This charger is made by ProMariner. The voltage output is supposed to be tightly regulated so that it can be left connected to and charging a 12-Volt lead-acid battery for long periods without damage to either the battery or the charger. It is not really designed to provide a restoration of a deep discharge; it is intended to keep a battery at float-charge level for long periods. See

http://www.promariner.com/en/10116

The description of the charger on that webpage seems to just be boiler-plate copy; if that little charger has all those microprocessor in it, I would be surprised. The label on the charger I have had for many years says:

    PROMARINER
    ProSport 1.5 On-Board Battery Maintainer
    16-Watt Fully Automatic 12 Volt Battery Charger
    13.4 VDC Finish
    117 VAC +/- 20% Input 0.5 Amp
    Certified to UL-1236 Marine
    Ignition Protected

This charger was not very expensive, about $45 as I recall, I think this product may now be obsolete. There is a new 1.5-Ampere product that is described in the 2019 catalog. See this on-line catalog at

http://www.delzer.com/powerproducts/prm ... 15/#zoom=z

This may be the replacement for the older product I mentioned above. It looks more expensive. I could not find a reference to it on the website, just in this catalog.

In any case, I would not leave ANY charger connected to 120-VAC and charging a battery for long periods--say a month or two--without some human monitoring of what was occurring. And I would not expect a 1.5-Ampere charger to be effective at restoring a lead-acid battery from a deeply discharged state.

ASIDE: the last decade or so I have been leaving the boat batteries in the boat during the long winter storage. After about eight months of non-use, with no float charging--and no parasitic discharging--I generally find that the boat batteries have not lost significant charge from sitting idle. My usual procedure when getting the boat out of storage, which I did about ten days ago in mid-May, is to plug in the boat's battery charger to an extension cord and get the batteries under charge. The charger has two indicator lamps: RED for charging and GREEN for charged. When I first plug-in the charger, the indicator for GREEN comes on and remains on, indicating the charger is in the finish or float mode. I let the charger top off the batteries for two hours, and then I figure I am ready to use the boat.

Of course, the temperatures up here are much lower than in the Gulf of Mexico coastal area during the winter, and temperature affects the rate of self-discharge. So sitting outdoor in a cold winter means a lower self-discharge rate than sitting in the tropics for the same time duration.

jimh
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Re: Battery Maintainer for Boat In Storage

Postby jimh » Wed May 29, 2019 11:27 am

UPDATE: I just found the new Promariner 1.5-Ampere charger at a very good price--$30--from DEFENDER:

https://www.defender.com/product.jsp?pa ... id=3728474

Jefecinco
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Re: Battery Maintainer for Boat In Storage

Postby Jefecinco » Wed May 29, 2019 4:50 pm

Jim, thank you for the reply and for going to the trouble to both identify the replacement model and finding one for me at a very good price.
Butch

jimh
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Re: Battery Maintainer for Boat In Storage

Postby jimh » Thu May 30, 2019 9:06 am

The “shipping weight” listed for that new model is only 0.2-lbs. or 3.2-ounces. These modern devices are sure lightweight. (I think that figure must be in error; the six-foot power cord must weigh more than that.)

Jefecinco
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Re: Battery Maintainer for Boat In Storage

Postby Jefecinco » Sat Jun 08, 2019 10:20 am

Jim - We received the Promariner maintainer yesterday. I installed it on our new West Marine AGM Group 24 battery and it immediately went to "charging" mode. I expected it to automatically switch to "maintaining" mode after five hours of charging. It had not switched and the charger was very hot to the touch but not so hot I couldn't keep my hand on it. Both the charger power cord and battery were room temperature. I unplugged the power cord while we were out of the house for a few hours and plugged it in when we returned. After about three hours it was hot again and perhaps hotter than before. I unplugged it before going to bed. My thoughts were that the battery was not well charged before connecting the maintainer and the charging demands were higher than those for which the maintainer is designed. I hope the maintainer will switch to "maintainer" status thus reducing demand and causing it to operate at a lower temperature.

If the maintainer fails to switch modes soon I will disconnect it and use a larger charger to get the battery up to a full charge before attempting to use the maintainer again.

Do you have any thoughts on the problem?
Butch

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Phil T
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Re: Battery Maintainer for Boat In Storage

Postby Phil T » Sat Jun 08, 2019 4:31 pm

I would not expect a marine battery to last more than 7 years, regardless of use.
Member since 2003
1992 Outrage 17, 1992 Evinrude 115

jimh
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Re: Battery Maintainer for Boat In Storage

Postby jimh » Sun Jun 09, 2019 9:29 am

JEFECINCO--my older Promariner battery maintainer does not do a good job of restoring a high-capacity battery that has a significant discharge back to full charge. It will get rather warm trying to do that, and it seems like it takes forever. The battery I am using with the maintainer is a 70-Ampere-hour battery. If it becomes discharged--for example if I leave the chart plotter on the bench running for 24-hours by accident and the maintainer was not plugged in, then the maintainer will get rather warm trying to restore that lost charge.

The best pattern is to use the maintainer after the battery is back to near-full charge.

I don't have experience with the new model. You might get a better idea of what is happening by monitoring the battery terminal voltage as the maintainer is trying to maintain charge. If the terminal voltage is way below the normal float voltage, usually close to 13.4-Volts, that means the battery charge is not at full yet.

jimh
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Re: Battery Maintainer for Boat In Storage

Postby jimh » Sun Jun 09, 2019 9:35 am

Phil T wrote:I would not expect a marine battery to last more than 7 years...


The best pro-rated battery warranty period I have seen is 84-months: that is seven years. I had a Ford Autolite vehicle battery that was showing its age; it had an 84-month warranty period. I found a very faded cash register receipt: it was 84-months old. I guess the battery maker had a very good sense of the ultimate service life of his product.

Jefecinco
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Re: Battery Maintainer for Boat In Storage

Postby Jefecinco » Sun Jun 09, 2019 10:38 am

Thank you for the advice. This morning I connected our old (1970s era) Sears Sensacharger to the battery. It immediately dropped to a draw of four amps. That indicates the battery was barely discharged. I expect the charger to drop to zero amps within three hours or so. When/if that happens I will reconnect the Promariner Maintainer and report back.

I was able to buy the maintainer with two day shipping from Amazon.com. The cost was $39 plus tax. We are members of Amazon Prime primarily for television streaming so there was no additional shipping charge for the maintainer.
Butch

Jefecinco
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Re: Battery Maintainer for Boat In Storage

Postby Jefecinco » Mon Jun 10, 2019 10:01 am

I charged the new battery with our Sears charger until it switched to a zero amps setting. I then reconnected the Promariner maintainer and it switched to the maintainer mode within a few minutes. I left the maintainer on all night and this morning it was only slightly warm to the touch. It's good to know the maintainer is performing as advertised and that the battery accepted a full charge.

Now it's time to shop for a replacement battery charger for our almost 40 year old Sears charger. It has provided excellent service and reliability but I'm unsure of it's suitability for charging AGM batteries.
Butch

Jefecinco
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Re: Battery Maintainer for Boat In Storage

Postby Jefecinco » Sat Jun 29, 2019 9:41 am

I would not leave a battery connected to a charger or a maintainer for more than a week without checking it for any problems. For six months of storage I would remove the battery from the boat or al least disconnect the battery cables from the battery terminals. Before using the boat I would charge the battery.

AGM batteries are reputed to discharge at a slower rate when unused than vented batteries. That can be a useful attribute for batteries that will be unused for periods of several months.
Butch

jimh
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Re: Battery Maintainer for Boat In Storage

Postby jimh » Sun Jun 30, 2019 8:33 am

To get a lower self-discharge rate the battery needs to be made with ultra-high-purity lead. That is the factor that enhances a low self-discharge rate, not the method of construction. A few AGM batteries do use ultra-high-purity lead, but not every AGM battery does.

Oldslowandugly
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Re: Battery Maintainer for Boat In Storage

Postby Oldslowandugly » Sun Jun 30, 2019 9:16 am

I use a NOCO Genius charger. It can charge, maintain, and repair a battery. All this is done automatically. I keep my battery plugged in at all times at the dock. I charge it occasionally over the Winter. I have it wired to dock power and mounted under an aluminum cover to keep rain off. While "water resistant" it is not advised to submerge it. It comes with interchangeable attachments like alligator clips. There are many different models with many specifications. I paid around $50 for the G3500 model. It was the largest amp model that did six volts as well as twelve volts. I have had mine for six years with no problems.

Image

jimh
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Re: Battery Maintainer for Boat In Storage

Postby jimh » Wed Jul 03, 2019 8:51 am

I believe the charger shown above in a watermarked JPEG image is actually better seen at

https://www.batteriesplus.com/productde ... 4qEALw_wcB