Battery Charging Protection Circuit

[dfris2003]

Hi All,

Ok, so i got way to much time on my hands today. I have been rewiring my boat for a new trolling motor. This is a new boat to me but an old boat. I noticed a old house wire running to the back of the boat. I followed this thing to the very back, where the previous owner, had put in 2 bolts, and hooked the wires to the bolts, and then ran the wire to the trolling motor battery. This in sense would allow them to charge the battery without having to lift the hatch. Great Idea, but the area where he placed the bolts, are very close to water. Which could short the battery out, Im talking with in just an inch of the water line.

after pondering on this a bit, Im wondering if I could put a diode inline with the battery, to stop any dead short that would occure if the water crossed both bolts. Or maybe some kind of transister configuration would work? I know a little about eletronics, but not enough to design something. I could build it easy. hahaha

Anyone have any ideas on how i could build this type of charging system with some kind of protection? My other thoughts would be to install one of those trolling motor plugs and socket and wire it that way. I would look better, and the closing lid would help with water. I would be charging with a battery charger, just would be nice to just plug in and charge the battery with out having to open the hatch.

Thanks
Daryl

 

[bruceb58]

Re: Battery Charging Protection Circuit

Put a fuse inline that is just a little more than your charge current. That's the best you can do.

The water won't short the battery out.

 

[Silvertip]

Re: Battery Charging Protection Circuit

Put a fuse inline that is just a little more than your charge current. That's the best you can do.

The water won't short the battery out.

But anything metal that happens to fall across the bolts would create an instant arc welder. Get rid of this thing and use any of the charger connection set-ups.

 

[bruceb58]

Re: Battery Charging Protection Circuit

But anything metal that happens to fall across the bolts would create an instant arc welder. Get rid of this thing and use any of the charger connection set-ups.

Not if you have a fuse in there as I suggested.

 

[kahuna123]

Re: Battery Charging Protection Circuit

50 amp auto reset fuse is $3.99 at the auto parts store

 

[Silvertip]

Re: Battery Charging Protection Circuit

50 amp auto reset fuse is $3.99 at the auto parts store

It wouldn't need to be a 50 Amp unit. Anything a tad larger than the max output of the charger would work.

 

[dfris2003]

Re: Battery Charging Protection Circuit

Thanks everyone, Yea its jerry rigged. Its a good Idea, but bad design. Was thinking about some kind of relay on the postive side to keep the power off the bolts, until the charger was connected to flip the relay. Would like to use some kind of better connection, like a trolling motor plug, with a relay, and fuse. This way they would not even be a spark if crossed some how.


thanks agian
Daryl

 

[Silvertip]

Re: Battery Charging Protection Circuit

Thanks everyone, Yea its jerry rigged. Its a good Idea, but bad design. Was thinking about some kind of relay on the postive side to keep the power off the bolts, until the charger was connected to flip the relay. Would like to use some kind of better connection, like a trolling motor plug, with a relay, and fuse. This way they would not even be a spark if crossed some how.


thanks agian
Daryl

You are way overthinking this. Just get rid of the bolts, the ROMEX wire (or whatever it is) and use a trolling motor or similar style of connector placed anywhere in the boat. Use the mating plug with your battery charger so you have a very simple and safe plug in design that will not cause you an issue. No relay needed.