Trillium trailer 12V wiring

[Rick G]

I have been wondering about the interior 12V wiring for my Trillium. Lately there have been several posts on this forum asking whether the 12V system should be grounded to the trailer frame, or rely solely on an isolated negative return (white) wire, for various brands of trailers. I expect they are all the same electrically, so I thought I would ask TrilliumRV what they recommend.

My trailer has a factory installed ground wire to the trailer frame from the battery, and also a factory installed ground wire from the power converter to the trailer frame. As a qualified electronics tech, this seemed correct to me, but some posters seemed to feel that the 12V should not be grounded to the frame. The 6 feet of difference where the wires are connected to different points on the frame should make no difference whatsoever electrically, although for a house it might be different in rare cases.

For completeness, here is a paste of my entire email to Trillium RV and their response:

**************************
-------- Original Message --------
Subject: Trillium 12V grounding question
From: "Garvin, Rick"
Date: Wed, November 17, 2010 12:50 pm
To: <Projects@TrilliumRV.com>, <Service@TrilliumRV.com>

Hi,
I have a 1980 Trillium 4500. It has an old power converter in it
that does not have a charger. I hope you can help me with a question
about grounding of the interior 12V wiring. I am not concerned about the
running lights connected to the tow vehicle. My tow vehicle also does
not charge the trailer battery, and I am happy that way.

My question is: should I try to separate the 12V negative return
for the interior lights from the trailer frame ground, or does it
matter?

My trailer has a direct wire to the trailer frame from the
battery terminal. At present I have not connected this because the
battery is removed for the winter. However, it appears that the 12V was
originally intended to connect to the trailer frame.

The 110V power cord is grounded to the converter case near where
it enters the trailer, and the converter case has a direct connection to
the trailer frame.

The converter has a switchmode power supply for supplying the
12V. It is not the original converter for the trailer.

The 12V circuits from the battery and from the converter have
white wires for the negative (ground) side. All of the 12V fixtures have
both positive and negative wires running to them. So far so good. The
system appears to run correctly, as far as I can tell.

The 12V output from the converter appears to be also connected
to the trailer frame ground. I know this because I measure 0 ohms
resistance between the common side of the interior 12V light sockets and
the converter case (which is connected to the trailer frame) with an
ohmmeter.

I can't see any problem having the 12V side grounded to the
frame at the same time as the 110V circuit. The 12V is likely grounded
to the frame whenever the trailer is hooked to the vehicle anyway
because of the vehicle grounding, although I know that the hitch is not
a reliable ground connection.

But, I wanted to check to make sure that this arrangement is OK.
Thanks,
Rick Garvin

From: info@trilliumrv.com [mailto:info@trilliumrv.com]
Sent: Tuesday, November 23, 2010 7:59 PM
To: Garvin, Rick
Subject: RE: Trillium 12V grounding question


Hi Rick:


Yes, your summary seems to be correct. As designed, the trailer wiring and the car wiring are both grounded by the white wire and through the car/trailer frame. These points are electrically the same.
Since the power converter is not the original, I can't comment on the grounding for it. I would assume that this is the intention. You could try to contact them, or perhaps you can find docs online.

All the old power converters had very limited ability for battery charging. Given this restriction, I would run black & white wires to the vehicle charging system. That is the best way to charge the battery, and it's relatively easy & inexpensive. There's a descrption of this procedure on the website, if you need it.

Happy Camping
Tom Young
Trillium RV


***************
So, they agree that there should be a connection between the 12V negative wire and the trailer frame, which there is anyway whenever the tow vehicle is attached because the tow vehicle 12V is grounded to the car frame.
Hope that helps,
Rick G

[Roy in TO]

I don't know much about electricity but connecting the two systems together through the frame makes me wonder about a few things.

1. If there is a short in the 120V side, what effect would it have on the battery? Could the battery be damaged?
2. What happens to the charge in the battery if the trailer is plugged in? Does current run through the ground depleting the battery?

[Rick G]

Originally Posted by Roy in TO

I don't know much about electricity but connecting the two systems together through the frame makes me wonder about a few things.

1. If there is a short in the 120V side, what effect would it have on the battery? Could the battery be damaged?
2. What happens to the charge in the battery if the trailer is plugged in? Does current run through the ground depleting the battery?

Hi Roy,

No, there should be no effect in either circumstance. The 120V and 12V systems are completely separate, and happen to use the same ground, which is a 0 volt potential. When you are plugged in to a proper 120V single phase (ie, normal house current) circuit, the ground wire is connected to the actual ground (ie, a long spike is driven into the dirt near the circuit mains). Trailer wiring then connects the trailer frame to the ground, where it should be. The neutral wire in a single phase circuit is also connected to the ground back at the main panel, wherever that may be, so it is also at ground potential.

If the 120V shorts to ground, it would not affect the battery at all since the 12V positive wire from the battery is not connected to the shorted 120V circuit. The 12V positive wire is also not connected to the ground at all. If you replaced a 12V light bulb with a wire, causing a 12V short to ground, your battery would be damaged quickly. However, light bulbs burn up instead of shorting out when faced with overvoltage or overcurrent, so that would never happen in real life unless someone did it deliberately.

Similarly, the charge to the battery is unaffected if the trailer is plugged into 120V, unless you have a converter which charges the battery and so is connected to it through a circuit (which contains its own protections against reverse flow of current). If there is no battery charger working, then there is no common connection between the “hot” side of the 120V and the positive 12V lines. Even with a battery charger, the battery voltage conversion circuit separates the 120V input and 12V output sections within the charger, so there is really no connection of the hot wires ever.

If, by a long stretch, you had a converter in which the 120V side shorts to ground and that shorts the 12V from the converter to ground (which should not happen because of the separation of the 120V and 12V within the converter), and the converter was connected directly to the battery at that point (which should not happen because there is a physical switch so that the 12V system runs on either the battery or the converter but not both at the same time), if all those things went wrong, then the battery would see a short for the short time period (a fraction of a second) until the circuit breaker or fuse blew, which might conceivably cause some damage to the battery. However, the systems are designed so that this does not happen, and it could only happen if someone had reconstructed the converter to bypass all the safety features.

Hope that helps.
Rick G

[Gumpit]

I haven't even begun to get into the wiring yet of my camper. How does the battery charge? By the power supplied by the vehicle? I still have to convert the 4 pin over. I assume the new connector has the wire that goes to the vehicle battery and a wire to go to the brake controller. Or does the converter bringing the voltage down to 12v to charge the battery when plugged in? Or is it just an inverter to go from 12v to 110v? And if the lights are 12v is the inverter just for the outlets? Thanks Randy

[Rick G]

Originally Posted by Gumpit

I haven't even begun to get into the wiring yet of my camper. How does the battery charge? By the power supplied by the vehicle? I still have to convert the 4 pin over. I assume the new connector has the wire that goes to the vehicle battery and a wire to go to the brake controller. Or does the converter bringing the voltage down to 12v to charge the battery when plugged in? Or is it just an inverter to go from 12v to 110v? And if the lights are 12v is the inverter just for the outlets? Thanks Randy

As often happens with trailer stuff, the answer to your questions is : “It depends.”

The battery will not charge unless you have installed a system to charge it. This could be the converter if you have one, but many converters do not have a charger, and many trailers do not have a converter. Also, the old converters are said to have very poor quality chargers that will wreck your battery in the converters that do have them, so you would probably want one no older than the 90’s if you were going to use a charger in a converter.

An inverter is a different thing, to change 12V into 110V AC so that you can run house appliances from the trailer battery. It is not a factor in battery charging. A converter changes 110V AC into 12V DC (all voltages nominal).

Charging could also be through the 7 pin connector on your hook-up, which has a pin dedicated to charging, however, your tow vehicle must also be set up for charging, with a big fat wire from the alternator or car battery and hopefully something to electrically separate them so your car battery does not run down. My car does not have such a setup, and most don’t unless they have a factory tow option, and maybe not even then. If you only have a 4 pin trailer connector now, you would probably have to install a charging line from your battery if you wanted that feature.

You could charge through solar power which could be connected directly to the battery through a solar controller. Lastly that I can think of, you could have a separate battery charger to charge the battery when you are hooked up to shore power.

Personally, I have a solar system and a separate battery charger. I thought about installing the battery charger in the trailer permanently, but I also use it to charge the battery when I have pulled it out of the trailer for the winter, and I have also used it on occasion to help friends out who had a generator but no charger. So, I wanted to keep it separate. For ease of charging, I have attached a 12V lighter socket type plug to my charger and just plug it into a 12V socket in the trailer which is connected directly to the battery (through a fuse). This makes it really easy. If I get another battery charger for Christmas, I might install one of them permanently in the trailer, we will see.

Regards,

Rick G

[Frederick L. Simson]

Originally Posted by Gumpit

How does the battery charge? By the power supplied by the vehicle? I still have to convert the 4 pin over. I assume the new connector has the wire that goes to the vehicle battery and a wire to go to the brake controller. Or does the converter bringing the voltage down to 12v to charge the battery when plugged in? Or is it just an inverter to go from 12v to 110v? And if the lights are 12v is the inverter just for the outlets? Thanks Randy

1. If you have the "charge line" connected in your tow vehicle, the trailer's battery charges from the tow vehicle's alternator only while driving.
2. The Converter converts the Alternating Current sine wave to a Direct Current flat voltage level. It only works when you are plugged-in to "shore power"
3. An Inverter is totally separate equipment. It inverts timed portions of the Direct Current flat voltage level into an Alternating Current sine wave. It only works when you are "Dry Camping"

[Gumpit]

I have the 4 pin standard set up that I am converting to 7 pin. Basically it looks like I don't use the reverse wire at all. Then the white wire goes to ground. It then says to run the black wire directly to the battery via a 30amp relay. And then the blue wire goes to the brake controller. I have The black wire run up to the relay but have not connected the relay to the battery yet. Should I connect it to the battery or somewhere else so it only gets power when the key is on? There is no factory tow package so I can't just plug it in. I have a brake controller coming and I have a plug that I can plug into the harness that is up by the fuse panel which is what the factory setup would be plugged into if it had a factory tow package set up. I just need to connect the wires from the plug to the controller. Then the blue wire from the 7 pin conector and I should be all set. But again. Should I make it so the one black wire from the connector be switched? Thanks Randy

[Joe MacDonald]

If you run the 30 amp black wire through a relay, the relay should be powered by a circuit that is only live when the key is on. this works like an isolater. I think what you are talking about is in fact a 30 amp breaker which should also be used like in the picture below.
[IMG]file:///C:/DOCUME%7E1/JOEMAC%7E1/LOCALS%7E1/Temp/moz-screenshot.png[/IMG]

[Gumpit]

YouTube - Trailer Brake Controller Installation - 2008 Toyota Tacoma - etrailer.com

I think it is around 3:32 that says it goes right to the circuit breaker and then straight to the battery.. Any idea where on a 2007 Tacoma 4 cylinder 2wd It should go first? Or can I modify an old Ford type starter selenoid to do what I need? Randy

[Joe MacDonald]

the solenoid is only needed for the charge line, and an old ford solenoid would be perfect, I know exactly which one you mean.
I would go from battery to fuse (inline), from fuse to solenoid,from solenoid to charge terminal on trailer plug. You might also consider a fuse at the trailer battery in case of a short in the cable between the trailer and the solenoid on the truck.
I'm not sure what wire to pick up in the toyota as a line to power the solenoid, that you'd need a wiring diagram for.

Joe

[Gumpit]

I was in my camper earlier and wanted to see how well a ceramic heater would heat it up. After a while it tripped the circuit breaker on the inverter. I am not sure if I have the switch in the right position. Is there a way that it will run right off the 110v to the outlet or does it all run through the inverter? Randy

[Joe MacDonald]

it should be running through the 110 at all times, the converter is to give you dc power for your lights. some of those ceramic heaters draw almost the limit for an average circuit breaker.
Add a long and possibly undersized extension cord, and it's going to trip.
what converter do you have in your trailer?
a picture would help.
Joe

[Gumpit]

It may be the extension cord then. I have to move it this wekend after I clean out from under my carport. I will runa shorter cord and see what happens. Thanks Randy

[Perry J]

Randy, I have the same truck. Buy a self resetting 30 amp breaker at an auto parts store and run the black wire to it and then the battery. You don't need a solenoid or anything else.
John

[B and TW]

I wouldn't recommend running anything that generates heat off of an inverter. Anything that generates heat is very inefficient when powered by electricity.. The inverter in this situation is likely JUST able to handle the draw from the heater, then given enough time the device heats up, and as electronic devices heat up they become less efficient at what they do, which causes more draw causing a fuse/breaker to pop.

[Davie B]

Originally Posted by Joe MacDonald

the solenoid is only needed for the charge line, and an old ford solenoid would be perfect, I know exactly which one you mean.
I would go from battery to fuse (inline), from fuse to solenoid,from solenoid to charge terminal on trailer plug. You might also consider a fuse at the trailer battery in case of a short in the cable between the trailer and the solenoid on the truck.
I'm not sure what wire to pick up in the toyota as a line to power the solenoid, that you'd need a wiring diagram for.

Joe

Just to understand: The relay is in the circuit to make sure you don't run down the TV battery while the engine is off but the trailer is still plugged in?

[Joe MacDonald]

yes that's right. I don't have one in mine, because I don't leave the plug connected unless I am towing

[Davie B]

I do the same but still think a relay is a smart idea; backing up my old befuddled brain when I get in late after a long trip.

[Gumpit]

O.K. I have the trailer back from getting a new axle. I am going away next week and it is going to be cold. I would prefer to use a ceramic heater instead of the propane furnace. I still have the problem with the circuit breaker blowing after a few minutes of running only the ceramic heater and nothing else. It has a Progressive Dynamics Converter. The outside power cord goes into the converter and it acts like a circuit breaker for all the 115vac appliances as well as the 12v. My question is. Can I bump up the 15amp breaker to a 20 amp( and I wouldn't go higher) and see if that helps from tripping the circuit or do I run a seperate power feed on an ouside cord and have a dedicated outlet only for the ceramic heater?

it is the pd6921w2
http://www.progressivedyn.com/servic...ued/pd69xx.pdf

[Bill K]

Try and find somebody with a clamp on amp meter and find out how many amp's you are drawing.
You may have a weak breaker.

Bill K