And yes, it is ok to leave that terminal unused.Īs for the wire size as well as the connector to use, I need to do some searching in order to answer those questions. And no, you can’t use the 7-pin as it’s terminals can’t handle that much current. And trigger it with a key-on source so the batteries are only paralleled when the key is on - and hopefully the engine is running.Īnd yes, you need a heavy gauge wire to run back to the trailer.
Instead I’d use a continuous-duty relay that can handle the full output of your alternator. That means that your vehicle battery can be at 14.4 volts and the trailer battery at 13.7, so it won’t be getting a good charge and it’ll take a lot more time to charge it. That’s because they have a significant voltage drop across them - up to. I don’t particularly care for diode isolators. Ray - That diagram is good, except I think that is a diode-type isolator as it doesn’t show a trigger wire that a relay would need. Something like this, which is basically the same as Gary's diagram except it makes more sense to me for some reason (cause I is a stupid): Would I still need to utilize the 12vdc lead from the 7-way connector to maintain a charge when the isolator isn't sending charging power to the battery? Or is it okay to leave that 12vdc lead unused? So, this Isolator, wired as shown in Gary's diagram, would allow the momentary charging of the auxiliary battery only when needed. Can I ground the battery to the trailer, or should I ground the battery to the truck frame? Then run a good hot wire (what gauge?) all the way from the engine bay to the rear battery. So I am thinking I need to mount an isolator under the hood near the factory battery. Anyone think that is a bad idea? Good, i'll get on it! So, this is what I am thinking.I get a couple of gophers and a squirrel cage, mount it to the trailer and have the gophers charge the battery. Give me an engine and I can tear it down and put it back together, but give me a winch and all I can do is look at it.įrom what I can see online, the factory 7-Pin harness will not charge an auxiliary battery, but it can maintain a charge. And you'll probably pay 1/2 of that just to get a continuous-duty solenoid capable of handling the full output of the truck's alternator.Īll this is so confusing to me. Personally, the ~$100 for the CH smart isolator is money well spent for the peace of mind knowing you won't be stuck in the back of beyond because you drained the batteries. That way the engine will still run and charge the main battery and you won't be stuck. But the CH system disconnects the two batteries from each other if they get down to 12.7 volts for a minute. And then both batteries are so low you can't start the truck again. With the Ford wiring if you have the truck running and use the winch a bunch it is possible to pull both batteries down to the point where the engine dies for lack of ignition. Oh yes, there's another difference between Ford's way and the CH way. But both use a continuous-duty relay that is capable of carrying the full current of the alternator. The main difference in that and the way Ford did it are that Ford triggers the relay with the Accessory or Run power where the CH unit is triggered by the electronics in it to parallel the batteries when the main battery is above 13.2v for two minutes. Here's how Cole Hersee's smart battery isolator is to be wired. The one I'm talking about connects the two batteries, but only when the vehicle is running. That's just the one the light-duty switches turn off/on to control the winch. From the diagram and instructions you posted the relay that came with the winch is the one that is in the "solenoid box". I'd be surprised if the winch came with the relay I'm talking about, which parallels the vehicle's battery with the trailer or winch's battery.