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Question about two batteries, charging, and wire size.

Discussion in 'The Garage' started by divorced, Jul 18, 2005.

  1. divorced

    divorced 3/4 ton status

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    I want to put a small electric winch on one of my trailers. I have an extra battery to mount on the trailer to power the winch. To charge the battery on the trailer I want to hook it up so that it can charge through the parking light wire on my 4 pin trailer plug, that way I can hook up my trailer plug and turn on the parking lights to charge the battery. I will place a switch on the "charge wire" for the battery so the trailer lights don't remain on when the truck is disconnected, and flip the switch on the trailer only when I want the trailer battery to charge.

    Now the questions:

    If the trailer battery would become low on charge from sitting too long and I turn on my parking lights to charge it, will the small trailer light wire be large enough to charge the low battery?

    If a dead battery is connected to a good battery with just a small wire, will it melt the wire? Or will the charge slowly transfer from the good battery to the dead battery?

    It seems to me that I should be ok because it seems like batteries can accept a charge only so fast, but I don't know for sure. Opinions, ideas, and answers are welcome :ears:
     
  2. The Butcher

    The Butcher 1/2 ton status Premium Member

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    This might not be much help (particularly if you want to operate the winch when the trailer is not hooked up to the truck), but why not do a quick disconnect similar to what Warn uses when you do a receiver hitch mount winch? Put the disconnect beneath the rear bumper of your truck and run the wires directly to your truck's battery. Of course, this does you no good if a buddy wants to borrow your trailer, or if you want to run the winch when the trailer isn't hooked up. But, it might be easier than figuring out a charging system for a remote mount battery. Just my .02
     
  3. divorced

    divorced 3/4 ton status

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    I have some heavy duty quick disconnect things to do it with, but as you mentioned that will limit the number of vehicles able to charge the battery. I have 4 trucks of my own to pull it with, my Dad's truck if I need it, and a few friends that may borrow it. I do appreciate the suggestion though. ;)
     
  4. BozoWise

    BozoWise 1/2 ton status

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    You will need a larger wire to charge the batter. And an additional ground. The RV 7 type plug has a pole to charge a battery on it, but it is for a small 12 volt battery designed to engage the electornic brakes if the trailer comes unhooked from the tow rig. If you want to run a full 12volt battery you need to do as suggested and run a large ground and 12 volt from the truck. I suggest using a disconnect like stinger offers or I have seen it done with welding lead connections. I can send you the stinger style if you can't find them locally. You will need a minimum of 4 guage but I suggest 1/0

    Here is another one similar to the stinger http://www.quickcar.net/electric/57704.html
     
  5. dave_90_blazer

    dave_90_blazer 1/2 ton status

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    a fully chagred batt will run a winch to pull a vehicle onto a trailor fine several times, don't worry too much about multiple tow vehicles, if neccessary, charge it at home with a batt charger
     
  6. divorced

    divorced 3/4 ton status

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    It is actually a small boom/hoist trailer that the winch (ATV winch) will be going on. It won't have much planned usage, just spur of the moment type usage if we need something moved as we work. Below is a pic of some connectors I have for 4 gauge wire and here is a link to the trailer: http://coloradok5.com/forums/showthread.php?t=144093

    [​IMG]
     
  7. kyser_soze

    kyser_soze 1/2 ton status

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    I have that hookup on my trailer winch. using 2 ga. wire hooke directly to my battery
    [​IMG]

    I also have made a jumper cable hookup for rear hookup to the battery.
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    use a constant duty solenoid..

    I would wire up a constant duty solenoid(looks like a ford one,with a metal case--DONT use a bakellite ford style one,it will melt!)..you can wire it to the ignition so the battery on the trailer will only get a charge while the truck is running with the key on..this keeps it from discharging when its shut off,also isolates it from the rest of the truck when the key is off..

    I'd use battery or welding cable for the run back to the battery...or at LEAST a 10 gauge wire if charging current is all you want(I'd avoid using the winch with that small a wire though..)..you can get a "quick dissconncet" plug like the ones you have in your picture to join the trailer battery to the truck..dont forget,a ground wire all the way to the main battery is a good idea too..(late model trucks with computers need it most,to avoid voltage surges).. :crazy:
     
  9. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    we built a multi-mount for a warn 8K winch and installed a receiver on the front of the trailer. We mounted a battery under the deck of the trailer and some wing nut terminals to hook the winch into. The trailer is wired using a 7 prong connection and the one wire is an always hot connection. We ran that wire through a diode to the trailer so it will always charge but with the diode it shouldn't reverse and de-charge. It works but most the time whenever the trailer is in the shop just throw the charger on it to recharge it and if it is dead on a run can h ook up jumper cables to the wire mounts on the trailer. I'll get a pic later....
     
  10. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Here are some pics. Just ran though road construction so kinda muddy.

    DSC02345.JPG

    DSC02346.JPG

    DSC02347.JPG
     

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