Quick 12v Question

[Dave-O]

I just put in a fantastic fan and have a question. One of the pairs of wires at the vent have no power, the other pair does (Thicker #10 wire). Can I run the fan and a new light fixture from this pair, and how do I hook it up? Can I simply connect the two hots from the fixtures to the terminal and the same with the neutral?
Thanks for tolerating my ignorance.

-David

[68 Overlander]

David,
Did you investigate the reason the wires are dead? Might be as simple as a blown fuse or bad connedtion on the Univolt/distrbution panel. I wouldn't recommend loading up the wires and that Fantastic vent probably draws quite a few amps.
Randy

[59toaster]

Well my A/S is 13 years older then yours but here is my observation after takeing a good look at my power vents. There is both 110v and 12v up to the fan. On mine the 110 goes to a step down transformer mounted next to the motor to supply the 12v to the fan motor when on city power. I have a toggle switch that chooses the power source. Trace those wires and make sure your not grabbing the 110v lines or the city 12v lines after the step down transformer. They may be dead because the transformer is bad or they may be dead because the switch is on the oposite pair. Meter those lines carfully to make sure of the voltage your dealing with so you don't end up Headline news : A/S OWNER ELECTROCUTED.

[74Argosy24MH]

My fantastic fan draws 1.1, 1.3, and 1.7 amps on low, med, high. You can figure the draw for the light by dividing the watts by 12. Unless you have something else that is using a lot of power on that circuit #10 will be more than enough.
Just as you said, hook the hot and ground together.

John

[Dave-O]

59toaster,
That makes sense because:
The pair that doesn't work now, was the one that did work (I'm almost sure it was the pair attached to the old light).
I took the battery home to charge (it won't) I brought it back to check the fan before I sealed it. The battery is of unknown age, maintenance free that I added distilled water to. I trickle charged it for 10 days and then hit it with a real battery charger overnight.
When I hooked the battery up to the trailer--no 12v power at any fixture. So, I hooked shore power and, still no power to original pair, but the #10 pair has power. (checked with test light first, and then tried the fan and it worked). All other fixtures have 12v.
Doesthis mean if I have a good battery that the original pair will be back working, all other factors not considered (blown fuse, etc)?

[59toaster]

Originally posted by Dave-O
59toaster,
That makes sense because:
The pair that doesn't work now, was the one that did work (I'm almost sure it was the pair attached to the old light).
I took the battery home to charge (it won't) I brought it back to check the fan before I sealed it. The battery is of unknown age, maintenance free that I added distilled water to. I trickle charged it for 10 days and then hit it with a real battery charger overnight.
When I hooked the battery up to the trailer--no 12v power at any fixture. So, I hooked shore power and, still no power to original pair, but the #10 pair has power. (checked with test light first, and then tried the fan and it worked). All other fixtures have 12v.
Doesthis mean if I have a good battery that the original pair will be back working, all other factors not considered (blown fuse, etc)?

It's possible. Just depends on how it was wired. Maybe you poped a fuse when you were pulling it appart.
See mine is sort of strange to me. Instead of just have a single large 12v step down in a central location I have a step down at each appliance. One for each fan, one for the heater blower. Then at each appliance I have a City-12v switch.
The other possbility is A/S used that as a junction point and something else down the line is not hooked up,
Are you overhead lights on a wall switch or just a pull switch at the fixture? Did that location share a Light and fan?

[Dave-O]

Overhead light switch was at the fixture not the wall. I believe a fan used to be in the old vent as I found blades and an old motor housing in one of the bins that had a lot of repair and misc stuff.
That's what I thought the bigger set of wires was for--the old fan.

Just to clarify about the battery. It did work to some degree, but I had a phantom load on it and also the cold weather may have had a hand in its demise. lights would dim as you turned more on, even with shore power. That suggests a low charge or weak cell, yes? I'm a little bit more battery smart now, hopefully.

I just thought I'd ask some questions before I went back and tried tracking it, it's probably just a blown fuse. Bottom line: with shore power all 12v stuff should work.

[femuse]

I have a toggle switch that choses the power source.

David's trailer is a 72. We have a 71 & a 74 International. Both use the same system, so I guess his is the same as ours.
We do not have a toggle switch. All the switches are next to the fixtures.
All the lights & fans operate on 12v. When we are on 110, the 110 goes to the converter which then provides them with 12v. They made some changes between 1959 & 1971.

Chantal

[59toaster]

Originally posted by femuse


David's trailer is a 72. We have a 71 & a 74 International. Both use the same system, so I guess his is the same as ours.
We do not have a toggle switch. All the switches are next to the fixtures.
All the lights & fans operate on 12v. When we are on 110, the 110 goes to the converter which then provides them with 12v. They made some changes between 1959 & 1971.

Chantal

That makes much more sense. Less 110v to mess with. I have both 110v and 12v at every fixture. The lights have a 12v bulb and a 110v bulb.
My Univolt scares me. It says backfeeding the 110v through the inverter alows it to charge. Think about that for a second. That means with shore power the mail plug end is hot that goes to the front of the univolt. My Shore power cable is the same way. if it got kicked out you have live prongs laying there. I'm getting rid of a lot of that dangerious stuff when I redo the system.