Hey Guys, can you check out this pic below and tell me if its correct? I have seen so many schematics from people using winch off their starter batter or secondary, but now im confused. So i'll let you now what i do and dont want. My winch is 9500lb with 500amp internal relay and i want it mounted in my bed as seen in pic. I could skip the isolator and swap out deep cycle for another starter battery, but i don't like that option because i risk draining both batteries completely (although it would be nice to have double the capacity). I want to use the winch when truck is turned off too, which is why going the deep cycle route and using isolator makes sense. The winch probably wont ever be drawing its max potential amps, but just incase, i am going with the 500amp isolator which should be good? Anyway, is this wiring below correct for my setup? My only issue is, what if the deep cycle gets too drained and i want to keep using the winch? Do i just start the truck up and the isolator turns on and the winch draws power from the starter battery now?

 

That looks correct. If the deep cycle battery gets drained, you can start the truck, and run it off the starter battery/alternator... That'll work fine.

 

The thing to keep in mind is; when you connect the start battery to the depleted winch battery, the two will try to equalize charge levels, so you will initially get some rapid discharge of the start battery until you have two half charged batteries... and the alternator will take longer to charge the two back to full (especially if you’re still winching) so you might find yourself with a low change start battery if you shut down before a decent charge level is achieved.

 

I think at that point i'd have to keep the truck running. Once it hits 13.8v for starter batter, the isolator kicks on and starts to charge the secondary i believe

 

Battery and equipment manufacturers give guidance on proper cell balancing in parallels banks tthat allow for optimal battery life and performance. The link is a white paper from a fairly popular smart charger manufacturer. Hooking everything up per recomendations allows your system to work it's best. You could say the wiring diagram you've shown does not necessarily follow cell balancing best parctices, but hopefully the link explains that a bit bettter.. https://www.solar-electric.com/lib/w...d_charging.pdf


Your winch manufacturer should have a stall current rating for your winch. My advice is to find out what that number is and is and design the rest of your system around that. What I mean by that is size the wiring to not be a fire hazard with stall current flowing indefinitely. Not that the winch would be happy with you if you tried it but the wiring should be capable of it. Then fuse as near the battery bank as possible with a fuse slightly larger than the stall current on the winch. The idea is just to protect the wires in the event of a short circuit. Not protect the winch. That is up to the operator. 2nd edit obviously the idea the wire should be big enough to withstand the biggest current in the circuit indefinitely. Before I said stall current but the wire guage should be big enough to withstand the current you set the fuse at. This is important. My bad. Sorry.

As far as I know under sizing the contactor isn't necessarily a fire hazard but it would result in premature failure of the contactors. . I honestly can't understand why anyone wouldn't want to use the biggest baldest contactors known to mankind if you can afford it and just get her done once and for all. I hear that these albright 182 contactors are sweet and I want to try one soon myself. Edit. Not to say that I know that your 500A contactor isn't perfectly adequatte as I don't know the stall current of your winch, but, I have heard good things about the albright contactors. Just sayin.

The other thing., yeah I know I'm getting a bit preachy here, is I sure wouldn't be planning to run the winch without the engine running. The problem is that gets the batteries way down on charge and as soon as you crank the truck back up, the alternator has to run wide open throttle for an extended period to try an catch back up. You gotta be nice to those things or they can overheat and die prematurely. I'm even planning to upgrade from my factory 130A to an aftermarket 250A behemoth when money allows to help it stay all caught up and healthy doing so.

 

oh yeah one more thing. I think you are gonna have aa hard time run a winch off deep cycles. blah blah blah about idepp cycles higher internal impedance due to their lower plate count compared to starting batteries...sorry

 

I was reading a little more about different winch installations and realized one of the things I said last night seems a little shortsighted/ weird and not quite correct so more blah blah blah from me.

While it's probably true it would be a little nuts to try and protect the load with a fuse unless you like changing fuses. Another good way to do the protection that does add a form of load protection, without giving up that critical line protection, is circuit breakers instead of fuses.That avoids the nuisance of changing out the fuse. You onlyy need to wait til the breaker cools down and you can try again.

By understanding and utilizing the breaker the I2T curves you could pick the breaker size to prevent thermal overload of the winch. Since the breaker sizes to make this work would be well below the winch stall current rating, unlike the fusing approach I mentioned before, technically using circuit breakers as winch thermal overload protection is an even more conservative approach to protection than the fusing. Probably a good thing.

The problem I was reading of, that people running larger winches are running into, was that for really power hungry 12V winches the current draw is so big that finding breakers in fine enough resolutions of current rating values whos I2T curves make sense for a particular winch application can be challenging or impossible. But the solution is apparently paralled smaller value breakers which there was also some discussion about and I need to read more about before I try this myself....

 

Thanks for the info! I have actually since downgraded my winch and bought a 4500lb one. So at MAX it will draw 300amps. For my purposes of mounting in the bed and using it for my own reasons which should never exceed pulling more than 1500-2000lbs in short bursts, i think my schematic works. I will stick with deep cycle since they are meant to be drained down to max levels unlike regular batteries, and also because it will be separate from the starter battery. It will get some charge each time i start and drive the truck. You dont think the fuses are a good idea? Thats what everyone else does as far as i saw. Circuit breaker would be nice though since you just have to quick reset it (i think thats what you were getting at)

 

Fuses work fine, but since they are a pain to change out and you have to have replacement handy when you do change one out, setting them at a value so low as they would be useful for protecting the winch from thermal overload could potentially mean you'll need to carry several spares and the tools to change them. If you happen to get stuck in a place where you are pushing the winch to get free, that might mean a lot of fuse changing before you get unstuck and you better make sure you brought enough spares.

You could run both, fuses and breakers, but at the point you decide to run breakers, fuses would just be redundant and I don't see the point. ie if it were me it one or the other.

I still think running the winch without the alternator actively charging the system in parallel is going to be an alternator killer but there may be an aftermarket supplier out there whose created some heavy duty alternator that wouldn't die under those conditions. But that isn't going to be your only problem.

I believe you are going to end up getting frustrated with running the winch from isolated batteries.

Deep cycle batteries internal impedance is higher than starting batteries in an equivalent package. To get the instantaneous current capacity large enough for bursts of winching will require a massive bank of deep cycle batteries that would generally be considered impractical to haul around in a pickup. Too small of a bank wont hurt the batteries but the winch wont run or only runs for a second before stalling.

Whereas an isolated starting battery would have the instantaneous current capacity necessary, the extended duty cycle in winching, compared to engine starter cranking is going to be very hard on them and cause a short life span. Starting batteries can run the load but would kill themselves doing it. The closer spacing between the plates, of a starting battery, would short out quickly due to sulfate buildup.

If you do try it, please report back on your results. I am just speculating, but I do have some experience with this stuff.

Edit: Obviously if you plan to keep the load really light such as a low powered winch pulling across pavement without much elevation gain, all the concerns I mention get proportionally smaller. My truck weighs around 5600lbs. Get that thing stuck in deep muck and I'm not 100% my 12K would be enough, without a ****** block, for all situations.

 

I get all your points, and they could make sense if hooking winch up for normal purposes on the truck's front. Google threads still give me mixed answers because people use deep cycle with no issues and also others use normal batteries. I should clarify that my setup is the same as that of which is hooked up to the front of a trailer. As in, they do the same setup (or similar) as mine above in the picture. My winch is for my own purpose and although it will be used alot during the day, it wont be for more than a few seconds at a time (as in, 2-3secs, pulling a load of maybe 200-400lbs). The only thing i can think of that it would be using alot of power, is if i want to pull a bush and its roots out of the ground or something. At that point it would be pulling alot...not quite the same as getting a truck out of the mud, but still probably a few thousand lbs id imagine