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Another stupid 24 volt winch question (long)

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by wrathORC, Feb 2, 2003.

  1. wrathORC

    wrathORC 1/2 ton status

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    OK, so 24 volt winches can be had for dirt cheap compared to 12 volt winches (we're talking used of course).

    Many of us run two batteries. You can hook the batteries in series to get 24 volts. Piece of cake. You can run the rest of the truck off 12 volts piece of cake.

    However, you're bent over a barrel if the negative terminal to the winch is hooked to case ground. Does anyone know if the negative terminal of the winch motor is hooked to case ground?



    What are my thinkings you ask? Well, let's start with my setup. I have two batteries. I run off one all the time. The negative terminal of the auxilary battery is hooked to the block. I have a battery isolator between the positive terminals (for charging). This way if I get a dead battery all I have to do is jumpstart myself with one cable. I have a Furd starter solenoid and cabling to make it so I can jumpstart myself with the flick of a switch but it's damn cold outside to be doing stuff like that.

    Anyway, wiring up the batteries is simple for 24v. You let the main battery run the truck. The auxilary batter is isolated (no connections at all--ignore my previous setup). You hook the negative terminal of the main battery to the positive terminal of the auxilary battery (with a Furd starter solenoid between them). You then run the positive terminal from the main battery and the negative terminal of the auxilary battery to the winch. Fine and dandy as long as that negative cable never touches chassis ground. If it does, poof goes the electrical system.


    So, does anyone know if the negative terminal of a winch motor is connected to chassis ground?

    Or better yet, has anyone done this? Perhaps someone has a more simple way of doing it? Us electrical "enjinmanears" have a habit of making things more difficult than necessary.
     
  2. DieselJuggernaut

    DieselJuggernaut Newbie

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    I have a question for ya! where do u get cheap 24v winches... i cant find any that are fairly cheap? i already have 24v, so all i need is the winch. thanks
     
  3. Blue85

    Blue85 Troll Premium Member

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    Grounding? What's the problem? I think that you missed the bigger problem; how do you charge the 2nd battery? You could have solenoids to switch between series and parallel, but that bites because you can't winch and charge at the same time, not to mention reliability. So the logical thing to do is run two alternators and have a true 24V setup. All you have to do is mount the 2nd alternator so that its case is totaly isolated from the block and chassis. Then connect it's case to the positive terminal of the alternator you already have. The negative terminal of the 2nd battery gets connected to the same spot. Then the output of the 2nd alternator is 24V (really more like 27V) and goes to the positive terminal of the 2nd battery and to the winch. The charging current of the 2nd alternator has a local path through the 2nd battery and will not return back through the 12V portion.

    As for the ground, why shouldn't the negative terminal of the winch be connected to it's case? Your ground for both the 12V and 24V circuits is still the chassis of the truck. Your only big risk with the setup I described above is letting the 2nd alternator case or 2nd battery negative connect to the chassis. For example, if the 2nd alternator moves under load or when you're wheeling or if a tool makes contact. It's also a risk if somebody else ever works on the truck or tries to get a jump start from the second battery. But is't not that big of a worry. I think military Blazers have a system something like this.
     
  4. K5RON

    K5RON 1/2 ton status

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    Your ground question..... I think the answer is winch specific. Most winches I've seen have two terminals for the powerfeed. The direction of current is reversed to reverse(Payout) the winch. The negative of the battery is to ground the case only. IOW, you have two terms. on the winch, put 12v/24v to them without regard to polarity and the winch will spin in one direction, reverse polarity and the winch will spin in the other direction.
     
  5. wrathORC

    wrathORC 1/2 ton status

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    Find them from the military or on eBay once in a while. They're usually pretty cheap compared to the 12v ones because of the lack of demand. I mean, a used 12v winch usually only goes for a 100 or 150 less than a brand spanking new one.
     
  6. wrathORC

    wrathORC 1/2 ton status

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    I don't plan on winching all day. I guess it depends on what you're looking for. You can get solenoids that have a normally closed part so you can have a little ground wire for 12v charging when you're not using 24v.

    A second alternator is a chore. It's fine if you don't mind having it next to the ground where an AIR pump would be or if you don't have an air conditioning compressor or a York compressor.

    Next, you have to isolate that second alternator. That is a real chore.

    You also have power on all the time and are spinning an extra alternator all the time.


    I like your idea because the winch case ground is a moot point. I'm going to do some more thinking.
     
  7. wrathORC

    wrathORC 1/2 ton status

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    I'll be honest. I have only seen two winches apart in my life. One was identical to what you described (not chassis grounded) and used polarity reversal. The other winch didn't power out and was chassis grounded.

    I don't know if they do something crazy in winches these days. I, myself, think it's amazing they don't all burn up.
     
  8. Blue85

    Blue85 Troll Premium Member

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    To switch a battery between series and parallel would take at least two solenoids. You need one that is "Double throw" with one input and two ouputs, to switch the low side of the battery between chassis and +12V. The other one just has make or break a connection between Aux battery + and +12V. When the batteries are in parallel, the winch is connected to 12V, which should be fine as long as you don't use it. Solenoids draw a lot of current to stay activated and may get hot if they are not the expensive continous duty kind. You would want to activate them with the regular 12V circuit since at least it has an alternator and isn't as likely to drop in voltage enough to release the solenoids while you are trying to winch. Actually, though, the holding voltage is much lower than the pull-in voltage for a solenoid.

    I mounted a second alternator and it was easy. But isolating it could be a pain. If you could find the mounting equipment from a 24V vehicle, that should make it easier.

    You could also use a 12V DC-DC converter to slowly charge the second battery whenever the vehicle is running. This would allow you to keep the batteries in series all the time and not use any solenoids. However, if you ran the battery down while winching, you would have to open the hood, pull off the - cable on the 2nd battery and use jumper cables to charge it up again off the 12V system.
     
  9. wrathORC

    wrathORC 1/2 ton status

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    Ford used to (I don't know if they still do or not) have a starter solenoid that had a normally closed position (ie, big-assed dual throw relay). What it was used for is to turn off something that normally has power when cranking (so more power goes to the starter). I picked up my regular Furd starter solenoid for $5 about a month ago. I imagine the other kind is more expensive and I'd have to find a competent parts man to find one. It doesn't take much to keep a starter solenoid energized. Initially they do because you've got a coil that takes a lot of energy.

    I have no idea how I would go about isolating it without investing big money and potentially catostrophic problems. That big money would easily go above and beyond the OO (double aught) gauge wire and 12v winch cost.
     

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