Battery Charging while Benny is on a trailer

dannyleininger

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Last weeks trailering discussion got me to do some research which lead me to reread my Bennington Owners Manual. One statement that surprised me was Bennington’s recommendation that boat batteries “Never” be charged while on the trailer. For the life of me I can’t imagine why this could be an issue???

The boat would be completely insulated from any grounding, ie: Rubber Tires and a plastic wheel on the jack. Can anyone help me understand this?
 

BigD

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I could be wrong, but I think they are saying not to charge them while trailering to and from a lake or site. Can't imagine why a charge on a stationary trailer sitting in your covered shed, for example, is a problem. What other choice do you have if you trailer full-time ?
 

dannyleininger

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Straight from the Bennington Owners Manual

”Never charge your batteries while the pontoon is sitting on the trailer. This is especially true if the trailer has wooden or carpeted bunks. Take the battery out of the boat to charge it. The boat which was removed from salt water is not free of salt water, even if you have washed boat your boat and trailer. Salt build up under the pontoons, held by the trailer bunk wood/carpet is an excellent con- ductor and may cause corrosion as you charge the battery.”
 

ILLINOIS AVE

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Straight from the Bennington Owners Manual

”Never charge your batteries while the pontoon is sitting on the trailer. This is especially true if the trailer has wooden or carpeted bunks. Take the battery out of the boat to charge it. The boat which was removed from salt water is not free of salt water, even if you have washed boat your boat and trailer. Salt build up under the pontoons, held by the trailer bunk wood/carpet is an excellent con- ductor and may cause corrosion as you charge the battery.”
This is going to get interesting ! Take it away guys!
 

Vikingstaff

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So do you think this advise in the owners manual is very specific to those that use theirs in salt water due to the possible conductivity issues? I don’t trailer, and am in freshwater, so not an issue for me. Just catches me by surprise to hear it.
 

Potomacbassin’

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Email Bennington if you need some clarification, I'm sure they'd be happy to provide additional info. But obviously the manufacturer wouldn't put that in there without a reason, so it's either 1) good advice to save you trouble down the road or 2) small print so that when you go boohoo'ing about all the pin holes in your aluminum hull they aren't on the warranty hook.

My only experience is with glass hulls but plenty of aluminum hull owners and forums out there to ask around. If you're going to ignore the Owners Manual do a lot of research so it doesn't cost you big later on.
 

dannyleininger

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Email Bennington if you need some clarification, I'm sure they'd be happy to provide additional info. But obviously the manufacturer wouldn't put that in there without a reason,

Good idea...how does one actually email Bennington? Never done this?
 

Potomacbassin’

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Last time I just filled out the inquiry form on the website asking a technical question. A very nice lady got me in contact with an engineer and we had probably a 20 minute discussion via phone. This was last year so hopefully they're still willing to do that for current and prospective customers.
 

BigKahuna

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My boat is on its trailer and I have an extension cord plugged into it's onboard battery charger and both batteries are being maintained........ Never heard of that......
 

BigD

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My boat is on its trailer and I have an extension cord plugged into it's onboard battery charger and both batteries are being maintained........ Never heard of that......
Exactly. If you have to remove batteries to charge them, why sell on-board battery chargers ?
 

Potomacbassin’

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On board battery chargers are sold to the masses which would include non-aluminum boats, so I don't think those companies care one way or the other. Also the advisory seems to only take issue with charging while on a wet trailer, so that may be a specific situation where some stray current might be leaking through the hull into the trailer and causing corrosion at those contact points.

Bennington isn't the only manufacturer to advise against the practice, see below. I'm sure there are countless examples of people doing this for years without issue, but there's a reason why OEM's are putting this in the owners manuals. I'm just not smart enough to decipher why.

222A88C0-9A67-49A2-AAF8-2DFF02CECDD1.jpeg
 

lakelifeMN

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On board battery chargers are sold to the masses which would include non-aluminum boats, so I don't think those companies care one way or the other. Also the advisory seems to only take issue with charging while on a wet trailer, so that may be a specific situation where some stray current might be leaking through the hull into the trailer and causing corrosion at those contact points.

Bennington isn't the only manufacturer to advise against the practice, see below. I'm sure there are countless examples of people doing this for years without issue, but there's a reason why OEM's are putting this in the owners manuals. I'm just not smart enough to decipher why.

View attachment 28811
Very through research. The main key I think is salt water with the wet bunks. In this situation I could see the salt infused wet bunks conducting electricity. Also as far as manufacturers go I’m certain it is so they don’t get sued for any damages this could cause. I’m sure 99.9% of the time it would fine but the warning is for the one time it’s not.
 

BigD

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Very through research. The main key I think is salt water with the wet bunks. In this situation I could see the salt infused wet bunks conducting electricity. Also as far as manufacturers go I’m certain it is so they don’t get sued for any damages this could cause. I’m sure 99.9% of the time it would fine but the warning is for the one time it’s not.
Like buying medicine you've been prescribed, and every possible side effect known to man is listed so they can say I told you so. Lol
 

Potomacbassin’

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Probably. But my CEO had to retire early because the meds she was taken had a massive reaction to her body and almost killed her. I'd hate to be that 0.5%!
 

dannyleininger

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On board battery chargers are sold to the masses which would include non-aluminum boats, so I don't think those companies care one way or the other. Also the advisory seems to only take issue with charging while on a wet trailer, so that may be a specific situation where some stray current might be leaking through the hull into the trailer and causing corrosion at those contact points.

Bennington isn't the only manufacturer to advise against the practice, see below. I'm sure there are countless examples of people doing this for years without issue, but there's a reason why OEM's are putting this in the owners manuals. I'm just not smart enough to decipher why.

View attachment 28811
Interesting that the wording from Manitou is word for word the same as Bennington’s!
 

dannyleininger

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Straight from the Bennington Owners Manual

”Never charge your batteries while the pontoon is sitting on the trailer. This is especially true if the trailer has wooden or carpeted bunks. Take the battery out of the boat to charge it. The boat which was removed from salt water is not free of salt water, even if you have washed boat your boat and trailer. Salt build up under the pontoons, held by the trailer bunk wood/carpet is an excellent con- ductor and may cause corrosion as you charge the battery.”

UPDATE:

I received a call back from Mitch Wolf, our area (Orlando) Customer Service Rep. Nice guy! He responded that he’d spoken to Engineering and they said Battery Charging on a Trailer is no problem. Actually, Mitch had never read this in the manual before, so I directed him to Page 15 of the 2018 Owners Manual. After reading it himself he responded that my Manual was quite old...

I decided to download the new Owners Manual and it is quite the Thesis on all thing boating. However, nowhere does it mention the above issue. Also, I was clear the new Manual came from Polaris and there were several leftover references to Polaris. Well, they to own Bennington :))

I believe the moral of this story, as stated by others, is to simply not charge the batteries on a “Wet” trailer, but only out of an abundance of caution IMHO.

Thanks for all the great comments! Happy boating!
 

Potomacbassin’

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An additional update -

Bennington's head of engineering was kind enough to respond to my inquiries and he also had to do a double take. My 2020 manual has this language as well, and after talking internally they will likely be removing this from future owners manuals - they have not seen issues for many years.

Additional takeaway - when a manufacturer's engineering department is willing to give out personal cell #'s to resolve issues and listen to feedback from customers, owners should have confidence in the product they purchased!
 
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