WARNING this thread contains misleading information - ASSUMPTIONS I MADE based on things I read elsewhere on this forum. See my third posting in this thread for corrections and clarifications.
I have a 2005 Sliverado 1500HD with the towing package and I have two questions about the auxiliary circuit.
If I wanted this to be like the Ford circuit where it is powered off unless the ignition is on, is it easily done?
Will this line provide enough power to charge a 100Ah battery located on the trailer? Would I simply connect the positive terminal of the battery to that line, or would a charge controller be needed? (ok, that was the third question, but lets call it 2a ;-)
Posted 2006-08-16 3:42 PM (#46763 - in reply to #46747) Subject: RE: Auxilliary on Chevy
Member
Posts: 11
Location: Oklahoma
Chris,
You are the first person I have ever seen to want the ignition switch to operate you auxiliary power. Most people I have talked to have wanted the Fords changed. And we have done that. But on the Chevy I don't know how easy it would be and it may be something you would want the dealership to do especially if you have any warranty on the vehicle. But having the auxiliary on a switch is a good thing to save your truck batteries while your trailer is hooked up and sitting. You can actually reroute the wire to a toggle switch if you need to. As for the Hot line going from your truck to your trailer battery. Is a battery on your trailer right now? And if you remove it, does your lights work off just your truck alone? If this is so then the auxiliary is already tapped into your battery wire on your trailer. But if you remove the battery and your truck will not operate your dome lights on your trailer then you will need to tie the hot wire coming off your truck onto the battery. Just make sure your battery is properly grounded to your trailer. Your truck should carry some charge to your battery and keep it up while your vehicle is running. I would recommend installing a diode on the line coming from the truck to the trailer battery to keep the trailer from drawing power from your truck unless your truck is sending power to it. This can keep your truck from having a dead battery when your trailer is hooked up to it for a long period of time.I would also recommend installing a fuse from your battery out to any of your lights on the trailer so that if you come across a short you will know as soon as the fuse blows.
Posted 2006-08-16 11:59 PM (#46789 - in reply to #46747) Subject: RE: Auxilliary on Chevy
Veteran
Posts: 143 Location: southeast U.S.A.
I would recommend installing a diode on the line coming from the truck to the trailer battery to keep the trailer from drawing power from your truck unless your truck is sending power to it.
I'm having a hard time understanding this idea or am I missing something here? This might keep the truck battery from draining the trailer battery if the truck battery became low but fail to see how it would keep the trailer battery from discharging the truck battery since a diode only impedes the flow of electricity in one direction for dc current. Like I said, maybe I'm just missing something! ,Ardly
Posted 2006-08-17 6:55 AM (#46792 - in reply to #46747) Subject: RE: Auxilliary on Chevy
Expert
Posts: 2689
You COULD do it with a relay.
e.g. use the daylight running light circuit (or any other circuit that is live while the ignition is on).
Daylight running lights on = relay called = aux connected.
re diodes; fergettit.
There will be voltage drop between the truck's battery and the trailer battery anyway, the "long thin wire" problem, don't make it any worse.
Posted 2006-08-17 7:32 AM (#46796 - in reply to #46747) Subject: RE: Auxilliary on Chevy
Member
Posts: 46 Location: Ottawa, ON
I don't have a battery on the trailer yet. The trailer lights get their juice from the truck through the aux. I would like to install a battery on the trailer so that I can run lights, recharge cell phones, radios, etc. without draining the truck battery. Having the aux. live only when the truck is running would prevent the truck battery being used if I leave the trailer hooked up. Also, it ensures that a drained trailer battery would not be charged unless the truck was running. I'm concerned about the possibility of damaging the truck battery by connecting a nearly dead deep cycle battery to it. I suppose that one solution would be to use a battery isolator switch in the trailer. I could set it up so that the switch had to be manually set to 'charge' the trailer battery from the aux. line. I will probably start with that as it is probably a good idea to have an isolator anyhow. Chris
Posted 2006-08-17 8:21 AM (#46802 - in reply to #46796) Subject: RE: Auxilliary on Chevy
Expert
Posts: 2689
Originally written by 10Ha.Wood on 2006-08-17 7:32 AM
I don't have a battery on the trailer yet. The trailer lights get their juice from the truck through the aux. I would like to install a battery on the trailer so that I can run lights, recharge cell phones, radios, etc. without draining the truck battery. Having the aux. live only when the truck is running would prevent the truck battery being used if I leave the trailer hooked up. Also, it ensures that a drained trailer battery would not be charged unless the truck was running. I'm concerned about the possibility of damaging the truck battery by connecting a nearly dead deep cycle battery to it. I suppose that one solution would be to use a battery isolator switch in the trailer. I could set it up so that the switch had to be manually set to 'charge' the trailer battery from the aux. line. I will probably start with that as it is probably a good idea to have an isolator anyhow. Chris
Another possibility, which addresses what I think your concerns are, would be to add some resistance to the aux line in order to limit the charging/discharging rate. Then arrange to short that resistance out when actually driving the truck, e.g. on the way to/from camp sites, but not when actually there. Of course the SIMPLE approach is to just unplug the trailer from the truck. Totally or near totally discharged batteries have a high internal resistance, so there is little/no chance of them sucking too much current from the truck's alternator or battery when first (re)connected. The "long thin wire" effect also limits charging rate and is responsible for a lot of the incompletely charged battery issues in trailers. 40ft or more ?
Posted 2006-08-17 11:35 AM (#46832 - in reply to #46789) Subject: RE: Auxilliary on Chevy
Member
Posts: 11
Location: Oklahoma
Originally written by Ardly on 2006-08-16 11:59 PM
I would recommend installing a diode on the line coming from the truck to the trailer battery to keep the trailer from drawing power from your truck unless your truck is sending power to it.
I'm having a hard time understanding this idea or am I missing something here? This might keep the truck battery from draining the trailer battery if the truck battery became low but fail to see how it would keep the trailer battery from discharging the truck battery since a diode only impedes the flow of electricity in one direction for dc current. Like I said, maybe I'm just missing something! ,Ardly
Ardly, you are correct I didn’t proof read and missed typed. I would recommend installing a diode on the line coming from the truck to the trailer battery to keep the truck from drawing power from your trailer unless your truck is sending power to it, is what I meant to say, thanks. But a master disconnect switch on the battery would be just as simple and you have control of your auxiliary charge
Posted 2006-08-20 1:28 PM (#46988 - in reply to #46747) Subject: RE: Auxilliary on Chevy
Member
Posts: 46 Location: Ottawa, ON
Well don't I feel silly.
Based on what I've read on this forum, I assumed pin 7 commonly labeled Auxilliary could be used to charge a battery.
It turns out that on my 1500HD pin 7 is for reverse lights. On my 2006 Titan Classic gooseneck, pin 7 is not connected to anything.
I'm not sure where the I went wrong, but the interior lights are powered from pin 4 and that is where I'll have to charge the battery from.
<sigh> Now I have to figure out what to do with the wire harness I made up with a heavy blue wire on pin 7 and a lighter gauge black wire on pin 4. I can simply switch them around, but I will then have the colors wrong.
Posted 2006-08-21 7:41 AM (#47033 - in reply to #46988) Subject: RE: Auxilliary on Chevy
Expert
Posts: 2689
Originally written by 10Ha.Wood on 2006-08-20 1:28 PM
Well don't I feel silly.
Based on what I've read on this forum, I assumed pin 7 commonly labeled Auxilliary could be used to charge a battery.
It turns out that on my 1500HD pin 7 is for reverse lights. On my 2006 Titan Classic gooseneck, pin 7 is not connected to anything.
I'm not sure where the I went wrong, but the interior lights are powered from pin 4 and that is where I'll have to charge the battery from.
Now I have to figure out what to do with the wire harness I made up with a heavy blue wire on pin 7 and a lighter gauge black wire on pin 4. I can simply switch them around, but I will then have the colors wrong.
Chris
Don't worry about it, I used to work with someone who often used the saying, "the electrons don't care what color covering is on the wire, they'll go where they want to go".
BTW, this is documented under trailer wiring on the Forum's home page.
The fact that RV and horse trailers are opposite on those two wires, the vehicle manufacturers seem to follow the needs of the majority (on this if nothing else).
Posted 2006-08-21 8:55 AM (#47037 - in reply to #47033) Subject: RE: Auxilliary on Chevy
Member
Posts: 46 Location: Ottawa, ON
Originally written by Reg on 2006-08-21 8:41 AM
Don't worry about it, I used to work with someone who often used the saying, "the electrons don't care what color covering is on the wire, they'll go where they want to go". BTW, this is documented under trailer wiring on the Forum's home page. The fact that RV and horse trailers are opposite on those two wires, the vehicle manufacturers seem to follow the needs of the majority (on this if nothing else).
Being a perfectionist and having gone to the trouble of scrounging colored wires of appropriate gauges it is hard to let it go... I'll settle for using some colored heat shrink to change the wire colors.
I went back and took another look at the wiring info and still don't see any reference to the possibility that pin 7 (on the truck) could be for reverse lights.
Auxilliary on Chevy - Corrections added
