What connector to use externally on the boat to recharge dinghy battery?

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PNW

Veteran Member
Joined
Mar 22, 2024
Messages
42
Location
Seattle, WA
Vessel Name
M/V Changing Tides
Vessel Make
1985 CHB 38' Trawler
I'm setting up a little EV style charging station just temporarily until I make other decisions. The idea is that my dinghy runs off a 12v battery and upon returning to the dock I top it off.
Right now I use a 15-40A semi-smart charger but it's 120v residential automotive, obviously I'm not in love with this just sitting out on the dock! So instead I would like to simply use my third battery bank charging connection (sitting unused now) and pipe it outside with a weatherproof connector. Then put the battery in a nice vented enclosure and run the connector to a plug there, so would just tie up to the swim platform and plug it in Tesla style.

So what kind of connectors will work for this application, with a time horizon of 3-6 months, that won't be ruined by being around salty moisture 24/7?
I was hoping something like this Anderson setup would work or maybe could be modified with a silicone or something to be relatively weatherproof but I don't have experience with it, just theories.
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Marinco makes a small plug/receptacle set that is rated at 40 amps, they also have one at 70 Amps.


I use the 40 amp 3 wire version for the pendant controls of the davit, plus a couple of other receptacles for hand held 12V spotlights.

The receptacles hold up well as they have a push on cover.
 
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A possibly easier solution is to just connect a small 12v solar panel to the dinghy battery. This way, even when the dinghy is in the water, your small solar panel is topping off your dinghy. I leave my solar panel on top of the canvas which covers the dinghy all the time and find this saves the battery and keeps it topped off.
 
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Not sure what the distance/amperage requirements are, but I've used some pretty simple bulkhead mounts for outdoor solar installations - the one below is 10-AWG so fairly beefy (Similar to what @luna posted, but I think a bit more weatherproof). Bulkhead mount is handy, but you could also use free-ends to just plug together.


I've used the "Anderson" connectors the OP posted above. They are pretty bulky. If 10-AWG will work, I'd go with the ones above.

Peter
 
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Okay! Great feedback so far. I think that a solar panel ON the dinghy would be pretty cool, I may work on that next. I have an extra charge controller so can just put that into my powerbox I made. Thanks for the links, I'll do some research and try to post once I've got something worth showing. Cheers.

Josh
 
I once used an Anderson to connect an outboard motor. Andersons are used in electric forklifts, and since I was working as a forklift driver at the time it seemed the logical choice. But electric forklifts don't get rained on, they're indoor use only. It's also way bigger than you need. Any waterproof connector for 10 gauge wire would be better.
 
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Okay! Great feedback so far. I think that a solar panel ON the dinghy would be pretty cool, I may work on that next. I have an extra charge controller so can just put that into my powerbox I made. Thanks for the links, I'll do some research and try to post once I've got something worth showing. Cheers.

Josh
I just saw another boat with a dinghy identical to mine but using an electric trolling motor. Since I'm having some trouble with my gas outboard that got me thinking (which is dangerous). If the OB dies I may give that a try.
 
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I once used an Anderson to connect an outboard motor. Andersons are used in electric forklifts, and since I was working as a forklift driver at the time it seemed the logical choice. But electric forklifts don't get rained on, they're indoor use only. It's also way bigger than you need. Any waterproof connector for 10 gauge wire would be better.
Yeah right now I'm trying to think how I can use 2-3 flexible 100W panels as a "roof" on the dinghy, in a quonset hut shape. Then everything will be inside the power box. I was thinking like an EV it should have a charging plug but having it just charge while it's out is a much more elegant solution! Plus now I could use my entire battery getting somewhere and then just recharge the next day while hiking or whatever!
In the previous iteration I was running off 4x 6v GC batts, but it was sooo heavy haha. Made a nice seat. But yeah I'm going to explore how it does on lithium and I bet running that with 200W of panels in an arch would have like 5x the power-to-weight ratio.
Only a 14lb thrust electric motor, so imagine how long a 100Ah @ 12v lithium could go while still weighing only like 40lbs
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Think you would be money ahead to switch battery chemistry and carry it into the boat. I have a 3 HP Epropulsion on my 10' dinghy. Pretty simple to carry the battery into the boat and recharge it.

Ted
 
Okay! Great feedback so far. I think that a solar panel ON the dinghy would be pretty cool, I may work on that next. I have an extra charge controller so can just put that into my powerbox I made. Thanks for the links, I'll do some research and try to post once I've got something worth showing. Cheers.

Josh
For my Torqeedo motor, I have a flexible solar panel that just plugs into the battery. It was built and sold by Torqeedo for their motors. No controller needed. When out cruising, I threw the flexible panel on top of the bimini and ran the chord around and underneath and plugged it into the battery. The solar panel did a very good job of charging the battery even if we were using it a lot.

You might check to see if the manufacturer of yours has something similar. The panel was easy to tie down and rolled up into a tube for storage.
 
Yes I see what you both mean but I already have the motor and battery from other acquisitions, so I can't buy a new motor or batteries at this point, I've just got to have fun the most I can with various components in inventory.
 
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Okay it's recharging itself now! Thanks for the brainstorm. I'm going to work on moving them up into a roof next but this is great and saves me a huge hassle every day trying to recharge.
 
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