Electrical Help Needed

[Fairleigh]

I have a 72 25' that has an electrical issue. I do not have a bettery in it at all right now. When I plug it in all the electrical sockets, and the AC work, but the radio, the light fixtures, and most importantly the jack do not work? I would think it was a fuse issue, but I am new to this trailer and have only found one circuit breaker box with two breakers, and neither is tripped. I would appreciate anything to get me pointed in the right direction.

[funkill]

I am ABSOLUTELY no expert!! I just bought a '73 Overlander a month or so ago ... I knew nothing about RV electrical systems - and am grateful to all the members here who have helped me learn. I am thinking that the items you mention not working is because they are 12V items - meaning, you need the battery to operate them. I'm attaching a link that I found helpful in understanding the electrical system - the schematic was really the best info - you know, a picture is worth a thousand words.

The 12volt Side of Life (Part 1)

[cameront120]

Originally Posted by funkill

I am ABSOLUTELY no expert!! I just bought a '73 Overlander a month or so ago ... I knew nothing about RV electrical systems - and am grateful to all the members here who have helped me learn. I am thinking that the items you mention not working is because they are 12V items - meaning, you need the battery to operate them. I'm attaching a link that I found helpful in understanding the electrical system - the schematic was really the best info - you know, a picture is worth a thousand words.

The 12volt Side of Life (Part 1)

This is correct. All of the systems you describe as not working are 12V. You need to get a battery installed and charged for them to work. Hopefully your Univolt is operating properly and all of the related fuses are in place.

[Chuck]

well...not quite.

you need 12 volts on the circuits in question to operate them; not necessarily a "battery". that could be one possible source of 12v. another is a "converter", which converts 110v a/c power to 12v dc.
The trailer came with such a device; whether or not its still installed is another question. The original equipment "univolt" supplies 12v, and charges the battery at the same time.

[Fairleigh]

I have never had a battery in the trailer, but all the before mentioned items used to work when plugged in to shore power. I have a converter in the back under the gaucho that makes a little noise when plugged in. It is still making noise so I am assuming it is still working. Do I need to check the fuses on the converter? Is there a 12v fuse box somewhere in the trailer, or would all the fuses be right at the converter. If I hook the trailer up to my truck should the 12V stuff start working?

[Chuck]

Originally Posted by Fairleigh

I have never had a battery in the trailer, but all the before mentioned items used to work when plugged in to shore power. I have a converter in the back under the gaucho that makes a little noise when plugged in. It is still making noise so I am assuming it is still working.

well, its doing "something", if its making noise...but not necessarily "working".
But this is where you need to start the search for the problem.

Originally Posted by Fairleigh

Do I need to check the fuses on the converter?

yes.

Originally Posted by Fairleigh

Is there a 12v fuse box somewhere in the trailer, or would all the fuses be right at the converter.

I suspect that yours is probably the same as mine, and that the fuse panel is built in to the converter. there should be a knob on the front of the box; pull it open, and in there, you'll see all the fuses.
some models did have a separate fuse panel, but its usually located right next to the converter.

Originally Posted by Fairleigh

If I hook the trailer up to my truck should the 12V stuff start working?

not sure. try it and see.
I'm working from memory, here, but I think the 12v line from the tow vehicle goes through the univolt, before it can reach any of the trailer's 12v circuits. (otherwise, there would be no fuse protection).
It could be that the 12v panel in the converter isn't getting any power due to a loose or disconnected wire somewhere, but it will pass along the voltage from the truck to the 12v circuits.

[HowieE]

You definitely need a battery. The converter is a charger system and not intended to be a power supply. The battery will level out the draw as the load changes and if fully charged can supply more current than the converter alone.

As for the fact that things did work before and not now you have to find the fuses that supplied the 12 volt circuits. They may be incorporated in the converter. Check the output voltage of the converter before the fuses to be sure the converter is still working. The noise you hear may be the fan on the converter or it may be a 60 cycle hum in the transformer. In either case testing the voltage is the only way to be sure the converter itself is working.

[Chuck]

you don't "need" a battery for the 12v stuff to work. It might be "optimal" to have a battery installed, but the stuff should "work" with or without it. The lack of an installed battery is not the reason that his 12v fixtures are not working.

[HowieE]

Let me repeat my statement. You definitely need a battery. There are 2 reasons for this if you ever intend to leave home.

1 While you are not on shore power nothing operating off of 12 volts will work. Most noticeably the electric jack, if there is one, and the refrigerator are items you may want while not plugged in. Even while on gas operation of the refrigerator the control panel is 12 volts. Lights are nice in the evening also.

2 the battery is your source of power while unplugged. The converter is a charger and as such not intended to be a sole source.

[funkill]

Originally Posted by Chuck

I'm working from memory, here, but I think the 12v line from the tow vehicle goes through the univolt, before it can reach any of the trailer's 12v circuits. (otherwise, there would be no fuse protection).
It could be that the 12v panel in the converter isn't getting any power due to a loose or disconnected wire somewhere, but it will pass along the voltage from the truck to the 12v circuits.

Sorry - I am not trying to hijack this topic but ...... after recent inspection, I found that my AS doen't have the univolt in place any longer - but my trailer lights all work when tied to my TV. Is this unsafe? i.e. am I lacking fuse protection without the univolt converter/charger?

[azflycaster]

Originally Posted by Fairleigh

I have a 72 25' that has an electrical issue. I do not have a bettery in it at all right now. When I plug it in all the electrical sockets, and the AC work, but the radio, the light fixtures, and most importantly the jack do not work? I would think it was a fuse issue, but I am new to this trailer and have only found one circuit breaker box with two breakers, and neither is tripped. I would appreciate anything to get me pointed in the right direction.

I would think that you would have more breakers then 2, mine has 4. One input 30 amp, and three output. One for the AC and two others for everything else. If I trip the 4th breaker it shuts off the power to the converter.

[azflycaster]

Originally Posted by funkill

Sorry - I am not trying to hijack this topic but ...... after recent inspection, I found that my AS doen't have the univolt in place any longer - but my trailer lights all work when tied to my TV. Is this unsafe? i.e. am I lacking fuse protection without the univolt converter/charger?

When you say trailer lights do you mean the running lights on the outside of the trailer? Those are powered by your truck.

The one safety item that is missing from any trailer towed with out a battery is the ability to power the brakes in a break away condition. If the pin is pulled and the line from the TV has been disconnected, nothing will happen.

[funkill]

When you say trailer lights do you mean the running lights on the outside of the trailer? Those are powered by your truck.

Thanks Richard --- you'd think that would be intuitive wouldn't you! Guess I've got a LONG way to go.

[cameront120]

Originally Posted by azflycaster

I would think that you would have more breakers then 2, mine has 4. One input 30 amp, and three output. One for the AC and two others for everything else. If I trip the 4th breaker it shuts off the power to the converter.

The 72 Tradewinds only have two breakers. At least that's all mine has. I believe one is dedicated for the air conditioner. Since I have no a/c, I used it for my new Atwood water heater for the electric heating element. All other circuits in the trailer run to the other breaker. Both are 15 Amp. I hope that helps.