Hooking up a rear hitch truck winch to the engine battery...

softdown
softdown Solar Expert Posts: 3,925 ✭✭✭✭
edited May 2018 in Caravan, Recreational Vehicle, and Marine Power Systems #1
Trying to get into recycling old cars and trucks etc. Having used a come-a-long on a car with bad tires and a locked rear axle, I decided to get a big winch. There are dual hitch assemblies that allow the use of a winch while also holding the trailer in place.

The problem is that the battery is about 20' from the winch when using the rear hitch. Plus I use two different trucks depending on the situation.

One can transfer some degree of power by using 2 AWG jumper cables with decent clamps. But I am leary of the transfer of power from the jumper cables to the 2 AWG cable connected to the winch. Insufficient power would damage the winch I'm almost sure. The winch was about $500...don't want to ruin it but not the end of the world if it gets damaged. 

Is there a way to make 2 AWG jumper cables efficient enough at powering a rear hitch winch? The winch is rated at 13,000 pounds and has a 6hp motor rated at 4.5kw, series wound. 

The alternative seems to be using five sets of 350 amp Anderson type quick disconnects. You have seen these connectors on forklifts and they do seem to work quite well indeed. This is how the disconnects would be used: 
Install a couple feet of electrical cable on both batteries. Install quick disconnects on:
1) Couple feet of cable hooked to battery in both trucks.
2) Couple feet of cable hooked to winch.
3) Both sides of about 20' of 2 AWG cable - connecting winch to battery.
*This requires 5 pairs of quick disconnects. $100 and labor.

Bet you have not evaluated this scenario before...
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    edited May 2018 #2
    Here is another option: The jumper cable clamps seem to do alright on the lead battery terminals. One could save significant time and money just using the quick disconnects to hook up the jumper cables to the winch cables.

    When a truck needed the winch, bring the winch and the custom jumper cables with the quick disconnects. That is likely about as good of a connection as I will get. Certainly good enough. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #3
    Does not the winch not require ONE positive conductor and use the chassis for the negative 

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #4
    littleharbor2 said:
    Does not the winch not require ONE positive conductor and use the chassis for the negative 
    Seems like that should work fine. Yet everybody runs a positive and a negative to their battery terminals. 

    If I just grounded the winch and ran the positive that would sure eliminate a lot of cabling and connections. Though grounding the winch presents a possible challenge when trading it back and forth between trucks
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #5
    Seems to me the potential issue is voltage drop across the circuit. More voltage drop = higher current to run the load (winch). Jumper cable clamps are a terrible connection, but work for purpose because the current needed for a jump start is momentary. Run the circuit for some time (like running a winch) and things look different.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #6
    Using the chassis as a negative is a poor choice in my opinion, most automotive reliability issues are electrical, which are related to use of chassis negative, one reason Japanese cars are reliable is because they use a seperate negative wire to every component, as well as using relays instead of the switch carrying the current. The high current of a winch should have its own negative, which is why it's common practice to do so.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #7
    mcgivor said:
    Using the chassis as a negative is a poor choice in my opinion, most automotive reliability issues are electrical, which are related to use of chassis negative, one reason Japanese cars are reliable is because they use a seperate negative wire to every component, as well as using relays instead of the switch carrying the current. The high current of a winch should have its own negative, which is why it's common practice to do so.
    When you need a winch you usually need it badly. Good argument for running separate cabling. Though it is impossible to predict winch usage. I may never use this winch though that seems unlikely at the moment.

    Synthetic winch cables are really nice if you can keep them away from UV degradation.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #8
    Turned out to be a bit of a chore. Doesn't almost everything? I used 2/0 Aluminum instead of 2 AWG Copper. Why? Because it allowed the use of some scrap 2/0 aluminum. 

    The Dodge had a little bit of corrosion on the battery terminals. In spite of cleaning, all I got was a spark when engaging the winch. Conductive paste fixed that. 

    Conductive paste. Might be worth it. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,174 ✭✭✭✭
    #9
    Unless I am missing something, a 4.5KW motor on a 12v system would pull around 375 amps. 

    2/0 at that load will be close to a 1.2 volt drop. So, if your alternator/battery system pulls down to a typical 11.5v or 11.8v under a heavy load, it will be in the 10's at the winch motor under full load.

    A standard DC motor is generally not a constant wattage device like an inverter. So at the reduced voltage, and less than 13,000 lb. work load, it will balance out at a lower current.


    I always have more questions than answers. That's the nature of life.
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #10
    Marc Kurth said:
    Unless I am missing something, a 4.5KW motor on a 12v system would pull around 375 amps. 

    2/0 at that load will be close to a 1.2 volt drop. So, if your alternator/battery system pulls down to a typical 11.5v or 11.8v under a heavy load, it will be in the 10's at the winch motor under full load.

    A standard DC motor is generally not a constant wattage device like an inverter. So at the reduced voltage, and less than 13,000 lb. work load, it will balance out at a lower current.


    That all makes sense to me. To be honest, I never learned how to do such calculations. 

    I do know that winch motors receive a lot of abuse. Like winching, without the motor running, until the battery and winch quit. Sounds stupid but we may consider:
    1) Many winching scenarios involve a stalled/deal engine.
    2) Winch manufacturers may recommend a 650 CCA battery with no mention of current being supplied to the battery.

    So I would guess that winch motors are built with lower voltage in mind. Plus that current draw generally only lasts for a very brief time. Once the vehicle is rolling, one healthy person can often do the rest.

    There are widely available winching kits that use clamps for attaching to the battery and #2 AWG for a 20' run. Looks like I am ahead of that set-up. Thinking that forklift type quick connects  are probably good for a close to 100% transfer of power.

    Also....even Warn specified quick disconnects are only rated at 175 amps. All in all, I don't think a 375 amp draw is anticipated for more than a couple seconds.

    Then again...I could be wrong. Hate when that happens.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #11
    I imagine decent winches protect themselves from too low voltage and overheat situations. Irrespective of the voltage drop, running the winch at full rated output would heat it up pretty fast.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #12
    Estragon said:
    I imagine decent winches protect themselves from too low voltage and overheat situations. Irrespective of the voltage drop, running the winch at full rated output would heat it up pretty fast.
    Decent winch? This is pretty much what I am referring to here: https://www.harborfreight.com/12000-lb-off-road-vehicle-electric-winch-with-automatic-load-holding-brake-63770.html

    It has a 4.7 star rating and people always seem to say good things. It is available at Amazon under the Boar name and with synthetic cable. Synthetic rope is awesome if you keep it clean, dry, and out of the sun. 

    Not as good as a Warn but I'm not sure that I will use it more than once/year or so. If that. Who can predict the need for a winch?
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    edited May 2018 #13
    If people are interested in that winch, be advised that it takes several minutes to make the hook fit unto the rope. Teasing and pounding...that is why the price is amazing. https://www.amazon.com/OFFROAD-BOAR-Synthetic-Waterproof-Winch/dp/B071F4YCRF/ref=sr_1_4?ie=UTF8&qid=1526750595&sr=8-4&keywords=boar+13000+winch&dpID=51HPkvvVtYL&preST=_SY300_QL70_&dpSrc=srch
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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