Battery maintaining over the winter

J

justgotaboat

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I recently read a short article in BoatUS magazine (December 2019 page 97 “kappow") that says you shouldn't leave your batteries on a car style charger (it says the kind with the alligator clips meant for charging batteries) or the battery could explode from over charging and the production of hydrogen gas. The way it's worded, I first read it as while you are not on board the boat and gone over a period of time. I then re-read it and it almost sounds like you should never do it period.

I took my batteries out of the boat and put them in my basement. I have a batterytender plus 1.25 amp charger/maintainer (similar to the link below one on amazon). The batteries are interstate marine/RV srm27 with 750 cranking amps and 160 reserve) every week or so I swap the charger/maintainer from one battery to the other. I know the batter tender is an automotive product, but I'm using it in a clean dry basement just to maintain the charge on the batteries. Am I risking damage to the batteries by doing this? Or is this what I'm supposed to be doing?

Thanks!

https://www.amazon.com/Battery-Tend...plus&qid=1579976034&sprefix=battery+t&sr=8-11
 
Don't leave them on the charger. Just charge once a month for a day or so and use a hydrometer to see how well they are charged.
 
Don't ever use that charger in the boat because it is not explosion proof and it probably doesn't have proper ground protection and may cause stray current corrosion. In an emergency I have used one briefly with the batterys disconnected.
 
I would never use it on the boat. Only on batteries in the basement or garage

It claims it maintains the batteries and doesn’t overcharge them though. Still disconnect it? For the majority of the time? Just a top up every so often?
 
Years ago , my dentist had 2 wet cell ( 6-cap type maintainable) boat batteries explode in his basement , about a month apart, in the middle of the night while they were hooked up to a low-amp charger, surprisingly probably just a trickle charger. Acid everywhere, cement floor, walls , appliances... . It is unknown whether the ignition source was a spark at the charger clips or furnace/water heater burners.

Most any charger's instruction booklet will advise never charge in a space where there is not good ventilation .
Basements are terrible spots in which to charge, though that is too common.

He only charges outside or in an open garage now because he got tired of replacing batteries and repairing all the damage to his basement.

FWIW, AGM batteries are much less likely to ever outgas explosive hydrogen , though they do have a pressure relief valve in case they are overcharged. Once charged up, they self-discharge at a very low rate so they don't need recharging during 5 or 6 month winter storage like wet cell type . I always use a quality automatic digital display portable charger in ventilated area before and after out of the boat winter storage of my 3 AGM boat batteries.

I would never leave a battery on a constant maintainer charger.
 
agree, put hem on a charger once a month. I quit taking my batteries out of the boat years ago.. Charge them up well at haulout and i turn all the battery switches off and charge again just before launch in the spring. Works for me.
 
To the OP:
You should be fine with that particular charger.
I’ve been using Battery Tender Plus (the bigger ones) chargers for months at a time in my garage for more than twenty years and never had a problem with them.
Same with just about everyone I ever met in that hobby.
They’re smart chargers.
I hook them up to my Corvette and GTO when those cars go away for the Winter and leave them plugged in until the Spring.
I’ll even use them during the season if the cars are going to stay in the garage for any length of time.
They’re not for use on a boat though and you should never use them on one.
I leave my batteries in my boat all winter.
Like Gregory, they go away healthy and then I charge them up before the boat gets launched in the Spring.
 
quote:
Originally posted by Sandy

Years ago , my dentist had 2 wet cell ( 6-cap type maintainable) boat batteries explode in his basement , about a month apart, in the middle of the night while they were hooked up to a low-amp charger, surprisingly probably just a trickle charger. Acid everywhere, cement floor, walls , appliances... . It is unknown whether the ignition source was a spark at the charger clips or furnace/water heater burners.

Most any charger's instruction booklet will advise never charge in a space where there is not good ventilation .
Basements are terrible spots in which to charge, though that is too common.

He only charges outside or in an open garage now because he got tired of replacing batteries and repairing all the damage to his basement.

FWIW, AGM batteries are much less likely to ever outgas explosive hydrogen , though they do have a pressure relief valve in case they are overcharged. Once charged up, they self-discharge at a very low rate so they don't need recharging during 5 or 6 month winter storage like wet cell type . I always use a quality automatic digital display portable charger in ventilated area before and after out of the boat winter storage of my 3 AGM boat batteries.

I would never leave a battery on a constant maintainer charger.

Click to expand...


There does not have to be an ignition source or active charging for a battery to explode.

Last year I had a battery in my golf cart explode while I was sitting on it. I had just stopped by the 5th green and the people back on the 4th green heard it.

It will scare a person. I bought a whole new set of batteries.

George
 
I just put mine in the garage on top of a convenient piece of wood to keep it off the concrete, trickle charge it whenever I think of it - usually when I happen to be in that corner of the garage and notice it. Might be weekly, might be bi-monthly, but that deep cycle SLA is at least ten years old and still kicking. (AGM’s like the Optimas are nice and fancy and current tech kind of - but you let them discharge once and they are smoked for good. An old school sealed lead acid, long as you top it off every year or three, they’ll last a good long time)
 
once a month charge them on the lowest setting in your garage or basement .go on ebay and buy a cca tester for 20.00 bucks,read the instructions and end all the guessing,i have 2 1000 mca since 2014 last year they were fine
 
Has anyone else have battery tenders go bad? I have two that seemed to 'suck out' the charge of the battery. Did I somehow reverse the plug or something. Odd that two did the same thing...
 
I have never left mine hooked up to a tender, I charge them when I winterize the boat in Oct and if the weather in wintertime is good I'll open up the cover and charge them once or twice over the winter. A good battery should hold charge pretty well over 5-6 months though, I have a spare battery for my '07 Jeep and leave it in the garage, charged it for the first time after sitting more than 6 months and it was at 90% when I put the charger on. In a way its actually better NOT to leave them on a tender continuously, that can mask a weak battery that will soon fail when put in service. If it sits 6 months and is still at 90% and tests good with a load or CCA tester then you know it mostly likely won't fail during the season.
 
quote:
Originally posted by Gregory S

agree, put hem on a charger once a month. I quit taking my batteries out of the boat years ago.. Charge them up well at haulout and i turn all the battery switches off and charge again just before launch in the spring. Works for me.

Click to expand...

+1
 
Is a marine Battery 3-stage charger different from a non-marine 3-stage charger?
 
As an experiment this time I did not charge the batteries during the winter, just wanted to see how well both of them held a charge. I knew the older one (bought in 2013) tended not to hold a charge as well as the newer one (bought in 2015). I used my battery tester (new digital style) and the newer of the 2 bats (going on 5 years old) tested good but the older one (going on 7 years old) did not. So I replaced that one and I think ultimately not charging them too often will tell you if they are really good, or not. A good battery should hold its charge pretty well over 6 months storage. Charging it too often unless you have been using stuff on the boat can give you a false sense of security.
 
Non Marine charger == not ignition protected. When you start a fire at the marina and your neighbors boats burn, you won't be popular.
 
quote:
Originally posted by Gregory S

Non Marine charger == not ignition protected. When you start a fire at the marina and your neighbors boats burn, you won't be popular.

Click to expand...


I was referring to the OPs comment: I took my batteries out of the boat and put them in my basement.
 
Over the years I have done many configurations of keeping the battery's charged and have never seen one way or the other add more life to the batteries. My last way of dealing with this was to remove the positive lead, keep the batteries in the boat, no charging over the winter then in the spring reconnect the positive lead and charge with the boat chargers till the boat is launched. So from November till April or the end of March, the batteries just sat with no charging. Pulling off the positive lead ensured there was no power draw. Just be aware, at least on my boats, such items like the carbon monoxide testers and the bilge pumps were wired before the battery switch, so flipping off the battery switch did not kill the power consumption to the battery. Also, my boats have been in LI NY, if you live in an area where the winters are colder than mine, then maybe what I do is not good for you.
 
Be careful about removing and replacing the positive terminal on the battery when the negative terminal is connected to that battery.
Safe procedure to disconnect is negative first, then positive.
Safe procedure to connect is positive first, then negative.
 
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