Dead boat batteries?

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Aug 10, 2019
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Lowcountry, SC
There are some good videos on identifying parasytic battery drainage. Identifying the problem doesn't mean you can fix it (trolling motor controller drain, etc.), but a disconnect switch solves every parasytic drain issue.
 
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KsRancher

KsRancher

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Jun 6, 2018
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Did you have them charging while it was parked in the shed?

I was roasting batteries for several years but I would always charge them to full and only plug it in when needed. The past 3-4 years I have my boat plugged in any time it isn’t in the water and my battery problem went away.
No. I parked it and didn't have it plugged in. Sat a little over 4 months. The charger on the boat has 3 different settings that it does automatically. Charge, condition and auto maintain. I am guessing I should get a disconnect and leave it plugged in all the time.
 

Jeffro

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Coeur d 'Alene, ID
No. I parked it and didn't have it plugged in. Sat a little over 4 months. The charger on the boat has 3 different settings that it does automatically. Charge, condition and auto maintain. I am guessing I should get a disconnect and leave it plugged in all the time.
If it has all 3 charge profiles, then yes. Leave it plugged in all of the time. It'd be hard for any battery to last 4 months with no charging source.
 
Joined
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If it has all 3 charge profiles, then yes. Leave it plugged in all of the time. It'd be hard for any battery to last 4 months with no charging source.

Hmmm, mine has lasted with 4-6 months between rides for several years, with no charging in between. I store my boat indoors. And I don't use the disconnect, but only because my dry boat doesn't have any parasytic drain. I've had two batteries since I bought the boat in 2009.

Good sealed lead acid batteries, when isolated and stored dry, only lose about 3% charge per month.
 
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KsRancher

KsRancher

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I think the batteries are toast or charger is bad. Charged all day and they still show 0 volts
 
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I think the batteries are toast or charger is bad. Charged all day and they still show 0 volts
Take them to a battery outfitters or similar store and see if they can revive them. They saved a couple odyssey batteries for me that my onboard and regular charger wouldn’t touch
 
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KsRancher

KsRancher

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Take them to a battery outfitters or similar store and see if they can revive them. They saved a couple odyssey batteries for me that my onboard and regular charger wouldn’t touch
Going to take them back to Cabelas tomorrow. They have a 5yr warranty and I bought them a little less than 6 months ago
 
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Aug 9, 2017
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Montana
I have a disconnect switch, and a battery tender quick plug in. Two batteries linked together. Also installed two cheap battery monitors that light up to show charge level. Come late fall I pull batteries out of boat and RV and lug them to basement where they sit at 62 degrees all winter long and put them on a tender once a month.
 
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Dec 1, 2020
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Unhook your trolling motor after you get off the water it’s likely the culprit, even with my disconnect switch turned off my trolling motor did the same thing. I just unscrewed the plug under my hatch and the issue went away. I think the ipilot continues to search for a signal even with everything off.
 

Holokai

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Oct 5, 2021
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Hawai
Disconnect switch (Blue Seas, Perko, etc.) will save you the headache of chasing down a small parasitic load. Also, agree that you shouldn’t have too much drain on lead acid batteries but that’s under optimal conditions. If you have the charger then might as well use it if you can. Better to keep em topped off than letting them sulfate and having to recover them.
 
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