Quick probably dumb univolt question!

[DanB]

Ok, My son and I are having a pleasant arguement. (He's probably right, but I would admit it.)

Is a 1970 univolt suppose to "run" while only hooked up to a TV? No battery is installed. The shore power is not plugged in. The ground wire for the 110 breaker panel is not connected to the frame.

So did I screw something up?

[silverleeper]

Originally Posted by DanB

Ok, My son and I are having a pleasant arguement. (He's probably right, but I would admit it.)

Is a 1970 univolt suppose to "run" while only hooked up to a TV? No battery is installed. The shore power is not plugged in. The ground wire for the 110 breaker panel is not connected to the frame.

So did I screw something up?

Hi DanB, The univolt is not suppose to run while hooked up to TV. Your TV will maintain the trailer battery while towing. Install a battery. The system is not meant to run without a battery. The univolt converts shore power(120v) to 12v through the univolt. The ground should be connected to the frame. Don't confuse the the 12vdc and the 120vac circuit.

[DanB]

So when I'm at a rest stop, I pop inside the trailer for a cola. I turn on the lights. I am running off of battery. And the battery is being charged via TV.

So as long as I have a battery in the circuit, I will have light. Correct?

I try not to confuse the DC and AC system. I find doing that causes pain.

I just wanted to provide all the facts!

Thanks!

[silverleeper]

If your trailer is wired correctly you will get a "trickle" charge from the TV. The battery if charged will give you power to the 12v lights even if your not plugged into the TV or shore power. "trickle" The wire from the TV charge system isn't that big and doesn't give your trailer a big charge. It will kill the TV battery if you leave it plugged into the TV over night.

[Chuck]

Originally Posted by silverleeper

It will kill the TV battery if you leave it plugged into the TV over night.

well....no, it won't. Unless, I suppose, you leave all the lights on in the trailer, and the radio blaring, and the furnace running, etc, etc.

If you stop at a rest stop, with this particular trailer, as it stands (no battery), and you turn on a light in the trailer, and see that it works...its getting its power from the tow vehicle.

[pixiehat]

talk about newbie.. I'm sitting here reading this post, hoping to learn something as I usually do and wondering what plugging in a television will do to the univolt.. Boy, do I have a ways to go.. Guess I forfet a rivit.

Lee
NI7I

[DanB]

Don't worry about it. I've been on here several years, owned an airstream, and can't figure out what my Univolt is supposed to do when!

Also, I did the same thing with "TV" not long ago!

[DanB]

Originally Posted by Chuck

well....no, it won't. Unless, I suppose, you leave all the lights on in the trailer, and the radio blaring, and the furnace running, etc, etc.

If you stop at a rest stop, with this particular trailer, as it stands (no battery), and you turn on a light in the trailer, and see that it works...its getting its power from the tow vehicle.

Is this even possible?

[silverleeper]

Originally Posted by DanB

Is this even possible?

I think so, although Chuck doesn't. Is it worth the risk? If your not plugged into shore power you will be drawing some off the TV battery. Given the right circumstances you can kill the battery in the TV. Yes, it is slim...

[Chuck]

Possible? um, yeah. broken, if it doesn't work this way.

Ok, let me just qualify it a bit: depends on the "tow vehicle". (didn't say "TV").
On some trucks, the battery charge line is always hot; in others, its only hot if the tow vehicle has the key in the "on" position, and/or engine is running.

mine is always hot.

when that line is hot, 12v is being fed to the trailer's 12v system, just as the univolt does it, if its plugged into shore power. having the tow vehicle and trailer connected essentially "joins" their electrical systems. plug in the univolt to shore power, with the tow vehicle hooked up, and ITs battery will get a charge from the univolt, too.

[DEITZ645]

Originally Posted by pixiehat

talk about newbie.. I'm sitting here reading this post, hoping to learn something as I usually do and wondering what plugging in a television will do to the univolt.. Boy, do I have a ways to go.. Guess I forfet a rivit.

Lee
NI7I

Originally Posted by DanB

Don't worry about it. I've been on here several years, owned an airstream, and can't figure out what my Univolt is supposed to do when!

Also, I did the same thing with "TV" not long ago!

Lee and Dan,
The univolt / converter charger is responsible for taking 120 VAC and running your 12 VDC systems (most lights, furnace, 12 volt circuit of refrigerator, radio, 12 volt circuit of water heater etc...) and keeping the batteries charged.

Your 120 VAC appliances (TV, microwave, toaster, coffee pot, etc...) will ONLY run when plugged into 120 VAC shore power (that is unless you have an inverter which is a whole other bucket of worms).

When boondocking the univolt / converter / charger does nothing and you are drawing totally on the 12 VDC of the coach batteries.

When hooked up to the tow vehicle your vehicles battery and alternator provide the current to help run the 12 VDC things and trickle charge your coach batteries.

Univolt / Converter / Charger changes 120 VAC to 12 VDC.

Inverter takes 12 VDC and steps it up to 120 VAC.

[Chuck]

Originally Posted by silverleeper

I think so, although Chuck doesn't. Is it worth the risk? If your not plugged into shore power you will be drawing some off the TV battery. Given the right circumstances you can kill the battery in the TV. Yes, it is slim...

{mass confusion}

I agree with this statement. But this is not what you said before.

you said: "It WILL kill the battery". <----that is not true.

It could kill it. not very likely, unless you are using lots of electricity all night. The sentence previous to "it will kill the battery" implies that all it would take is the draw from the trailer's battery....that isn't true, either. On many occasions, I've started to run low on amps while boondocking, and have plugged the trailer into the truck for a little boost, just to get by until morning. never a problem...truck starts right up the next day.
Now, I wouldn't do this if I were alone and isolated...but with a group, or at a campground, where a jump is available if needed, no worries.

[silverleeper]

No confusion. I just like to play it safe. Posting is interesting thing. Some times your not as clear as you think you are. Maybe I should just leave it to someone else.

[Chuck]

Originally Posted by silverleeper

...Maybe I should just leave it to someone else.

NO!
its the "discussion" that makes the forum so valuable. input from everyone!

[richinny]

part of the equation is understanding just how much each device consumes.

we all know that leaving your headlight on overnight will usually result in a dead battery by morning. in the trailer, the heater fan is the big hog, followed by electric fans and a few regular light bulbs.

think of a battery like a checking account, if you take out too much, you're in trouble. you also want to keep the batteries from going below 50% to prolong battery life.

the univolt is more to maintain the batteries than to charge them up from dead.

[Lumatic]

Originally Posted by pixiehat

talk about newbie.. I'm sitting here reading this post, hoping to learn something as I usually do and wondering what plugging in a television will do to the univolt.. Boy, do I have a ways to go.. Guess I forfet a rivit.

Lee
NI7I

Are you talking about a 110v or 12v television, or a 110 TV run through a 12v inverter? But, neither will do anything to the Univolt. The 110 runs on shore power. The 12 v runs off the battery. Another factor for running a television off the battery is what is the amp/hour rating for the battery. Your average single series 27 battery is probably good for a couple of hours of TV watching.

[DanB]

Lumatic,

I believe he he mistakingly confused "TV" for television instead of "Tow Vehicle".

I've caught myself doing that also!