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Off season battery care......

BigKahuna

BigKahuna

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Our boat has been at the dealership since we took it out in November. We are waiting for a new replacement motor casing from Mercury because of a paint defect. Anyway, my boat has been on their lot about 75 yards from the showroom bldg. I normally just plug into the onboard battery charger and it conditions and maintains the batteries until next season but there is no electrical plug in the boat parking area. Today I ran about 250 feet of extension cords to the bldg. and charged the batteries for about 8 hrs. (In our old boat I used to take the batteries out and charge them in the garage) How do you guys maintain your batteries in the (For most of us) off season?!?
 
I charge it at the end of the season after the boat gets pulled. It then sits on a basement shelf for six months. A day before it goes back the the water, I charge it again. I have never found the need to maintain all winter.
 
My dealer stores our boat. He pulls the battery and puts a battery tender on it. Pops it back in in spring and good to go.
 
Batteries pulled at the end of season and put on my workbench with a battery tender until it's time to gett'er wet.
 
AuthorizedUser said:
I charge it at the end of the season after the boat gets pulled. It then sits on a basement shelf for six months. A day before it goes back the the water, I charge it again. I have never found the need to maintain all winter.
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I have a neighbor that leaves/stores his boat on his lift all winter. I asked him if he uses a battery tender. He told me once he parks it in the fall he doesn't do a thing to his boat until spring. He says it starts right up! It would be interesting to see how much voltage a battery loses sitting for that amount of time in the cold of winter.
 
Pull Boat and Jet Ski batteries. Store in garage from November to May. Only have two Battery Tenders for the four batteries, so I alternate weeks of maintaining charge. Occasionallly check them with volt meter. All good to go come Spring.
 
My last Benny got stored, shrink-wrapped, outside every winter for 10 years. Charged it up before I sent it to get wrapped, and then charged it again after I took off the wrap. Never had a problem.
 
I have had pontoons for 35 years. As I get older I learn what I need to do with regard to maintenance. I tend to do less maintenance as I get wiser. At the end of a season when you are using your boat less a weak battery will tell you if it needs replacing. If it cranks slow pull the battery and plan to replace it next spring. If it cranks good leave it in the boat thru the winter. Next spring if it starts the boat its good enough to take you dependability thru the season. My experience is that it will generally start the boat for 5 years in a row. If it does not crank fast enough to start the boat replace it before you start the season. A trickle charger will bolster a bad battery. Don’t go into the season with a bad battery bolstered by a trickle charger. A battery tender will make your battery last a bit longer but its not worth your time and potential angst. With regard to battery life you get what you pay for.
 
Not all batteries are created equal. I have a commercial Toro mower, a Simplicity mower, 4 wheelers, a Farmall 140 tractor, and a Kubota 3710 tractor. The Simplicity won't make it through a winter without a full spring charge. The 4 wheelers won't make it 3 months no matter the time of year. They are notorious for lousy batteries. None of the others have ever been a problem. No tenders. No charging. No nothing. Just like vehicles. And they all set for the entire winter without use.
 
WVFan4 said:
I put mine on a battery tender all winter long. I do wonder if it is actually needed. My John Deere is 13 years old with the original battery and it sits from November to April each year without anything done to it and it has surprisingly started up each year.
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I've got my lawn tractor battery on a tender too! Those batteries don't last long and will die without warning so I'll try to help it when I can.....
 
Sparkyduc said:
I have 2 batteries on my pontoon and each has a waterproof battery tender hardwired in. When I put it on the lift after the weekend I plug them in. I leave them plugged in all winter also. Get great battery life. All my toys ( motercycle, side by sides, Atv’s) are kept on tenders. Used them for 15+ years with great success.
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We have an onboard charger on our boat. I was asked if I use it during the season....... The answer is No! We use our boat at least a couple times a week. I feel that it stays pretty much charged up just by using the boat so we don't use the onboard charger in season. No need to!
 
A few additional thoughts -

Different battery chemistries, different self discharge rates. So a lithium vs AGM vs flooded will have a different answer as far as off season storage goes. Having owned many flooded deep cycle lead batts my experience was about an 80% remaining charge after about a month or two of storage. Flooded cranking batt may perform differently but my guess is you'll be fine as long as you're not storing for more than 4-6 months. One cheap way to check is to get a hydrometer from Amazon and check every few months.

Temperature also apparently impacts discharge rates, so colder will store longer than warmer ambient temps.

All else fails bring a portable lithium jump starter which should get you going as long as it's not completely dead. Probably a good idea to have that in your boat bag anyhow in case you get stranded at the tiki bar!
 
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Start the boat ever month works. Last week I lowered lift into water, started, ran for 30 minutes to get engine to running temp, and then cycled through some slightly higher RPMs. Too cold to take out but good to get batteries charged and fluids warmed and circulated. Also nice to find any issues now, have them fixed now, versus cranking in the late spring and see you have an issue.

Next start will be in a month. My mechanic says you dont have to do anything in the off season, since we dont winterize, just a fuel stabilizer.
 
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