Univolt Configuration

[FrankR]

The univolt is a very basic device. Most electronic/electric repair shops can easily repair and find any necessary parts. I am not trained as a bench repairman. I do not have any schematics or parts lists. I think Univolt went out of business because they were rarely replaced. Univolts are very tough and require some poor choises to destroy same. It is very difficult to diagnose parts and problems long distant via the net and a few words.
I buy about any converter I can. Most prices are about $35-50 for a 75-90 amp model. Transformers just cannot wear out. They can be overheated and the insulation fail or they maybe mechanically deformed, ie crushed. Some other RV guys have attached small fans to cool the unit. New converters can cost as much as $425 depending the electronics package. The new inverters are a terrific device that will do many battery tasks. I like the pure sine wave type inverters. The big name hi dollar units are the best. Good old Ebay is a great source for these units. I have an inverter in each RV and my puller Ford truck
Hey Creampuff, I have never heard of a silicone coated rectifier. Is this like a louvered gas tank? Some converters use a couple diodes to make the low voltage into pulsed ac and the battery "sees" this voltage as dc.

[Creampuff]

Frank :
The SCR is the component that screws into the hole in the center of the aluminum baffle(?).It is fed by a wire from the circuit board.It is the same as 2 on the other side (fed by wires from the transformer)but about twice the size.I tried to post a picture but can't get it to upload.I'm new at the attachment thing.

[WayWard Wind]

The things you learn late at night. Interesting discussion regarding Converters,Univolts & batteries. I'll admit to my lack of knowledge on this subject, so I'll ask some stupid questions. What's the differance between a converter & Univolt ? I think I may know, but increase my knowledge. When we purchased our 02 Bambi I never gave it a thought ( & of course no one told me ) that it was possible to over charge the battery. The discussion around a battery disconnect switch led me straight to the owners manual where it says " The Bambi has a master kill switch between the battery & the 12 volt distribution panel. The appliances & 12 volt acc. are designed to operate with the batteries in the system & the switch should always be in the on position". Am I right in thinking I should install a switch between the battery & the converter to avoid over charging my battery?
Best,

[FrankR]

There is no difference between a converter and a univolt.
I am not sure of what you wrote about the master switch. My idea of a master switch is one that controls everything. With the switch "off" nothing will operate. A battery switch is a switch that "opens" the power from battery to the system. I think also that a master switch in a Airstream is to prevent battery discharge while trailer is not being used. The reason for any switch is for better control of any system. Please ask lots of questions. I have some answers I have not yet used. Most discussions areabout getting the most fun and enjoyment from a great adventure.....

[Phil and/or Sue]

For your information, an SCR is a silicon controller rectifier, and and inverter traditionally refers to a device that "creates" alternating current (usually 120 volts) from a DC source (in tis case 12 volts).

A converter usually converts alternating current (120 volts usually) to direct current (12 volts in this case).

[Creampuff]

Thanks Phil:
Now that I have the correct terminology I can hopefully track down the device.Being electronically inept is hard at times.Give me mechanical things and I'm in my element!
I also understand that another term for SCR is 'thyristor".Would that be true,and since not all the numbers are on this part,does it matter significantly that I get an exact match?

[garry]

I think you may be in over your head and could get hurt and or cause damage to other things.
There are two families of thyristors,SCR's and Triacs.

Thyristors are semiconductor devices with three leads small current at one lead will allow a much larger current to flow through the other two leads the controlled current is either on or off.
SCR's is more of a switch that once on stays on until power is removed they also have three wires going to them.
I suspect you are talking about an SCR and you can swap out a larger one for a smaller one but never the other way and it is best to only go a slightly larger if you can find an exact replacment. BUT I still advise you to find a qualidied tech to help you out on this one.

Garry:

[Creampuff]

Roger that one Gary!
As soon as I can figure out why I can't post a picture,I'll get one up of the part.
Meantime,if I can find a parts counter-I'll just ask them to match my "whatchamacallit"!!

[WayWard Wind]

Frank-- Thanks for the comeback--I think I have a mess, not only a mess, but a confusing mess. you were correct in that the " kill switch " purpose is to basically shut-off 12v current when the trailer is not being used for some time. The current discussion to me appears to center around something different than what I have in the 02 Bambi. Couldn't stand the pain of not knowing so, went to the Bambi this A. M. ( after it warmed was +13 last night ) & woke her up from slumber to look. There is no fan --it's not hard wired-- has LOTS of wires coming out from both ends that go all over & the name Bard ? or something close. Couldn't tell, cause like all flashlights I own they never work when I need them. Went to the A/S owners manual--refers to a Magne Tec- wiring diagram shows fans plug-ins, a wiring board of sorts--the manual tells all about how to check them out --what they should read, etc.Nothing like I have-- FYI I have talked to A/S last summer on this very issuse, but cause I was new at this didn't press the issuse, to avoid looking dumb. Trying to use the winter time to see just how the insides of the Bambi looks & operates, but man is it difficult with the info A/S gives one. For the most part the manual I have is pretty useless. appreciate your thoughts. Thanks,

[MeToo]

Originally Posted by FrankR

Hey Pap, ya found me out. I did work for the film industry for 11 years in special effects. Very interesting world. My film work ended in 1973.

This is a great thread. One more question: It appears that I only have stock space for one battery. BUT we will be taking the Sov. into the wilderness and I'm wondering about adding in a second to increase my staying power. Any thoughts on this installation?

PS: Frank, I was a post production supervisor at Lorimar Television 1984-1990. I worked on Dallas, Our House and Max Headroom. Now I'm hiding out in Idaho just like you.

[rslaymaker]

I am planning to make a cross country journey this summer with my family. Unfortunately, I am still working on the electric aspects of the camper... and I hope to resolve the issues before I begin. My basic desire is to have the camper with electric while traveling. That is, to have the refrigerator keeping the food cold and in the event we arrive to a campground late, I can utilize power from my battery. So, I really need to avoid draining my battery of its power during this usage.

I have drawn the attache diagram, very basic... Does anyone have any experience with this configuration, can it work, any sources that will give me the directions needed to make this work?

As always, I thank you for your support.

[FrankR]

The connections while on the road are very simple, but some care and planning are required. I'm not a big fan of isolators. My choise for seperating the tow vehicle and tow car is a large HD 100% duty relay. The relay is controlled via the tow car;s ignition switch. Every time the tow car is stopped, the battery connection is opened. If the trailer battery is consumed, the tow car can start and drive away. A good choise of wire size between tow car and trailer would be #10 MTW stranded. There should be a fuse or circuit breaker located between the tow car battery and the relay. I prefer a new aircraft breaker but all the car stereo stores have all the required
materials. I also prefer to use a seperate electrical disconnect plug for the connections between the tow can and trailer. An easy disconnect has 4 connections in a single plug. I use 2 wires for each the "hot' positive and 2 wires for the ground negative. Just one extra plug to unplug.. Frank

[Pick]

Murphy, are you planning on running and apartment style fridge in your coach? I have a small one in mine. It draws 1.9 amps at 120 vac. This will translate to 20 amps at 12 volts. That is a lot of current to be drawn through a 50-60' piece of #10 wire, which is about the distance from vehicle alternator to battery in back of the coach. You would need a fairly large inverter to handle the starting current of the compressor.

That being said, and the fact that I do not know what kind of tow vehicle you have, here's what I would do if your TV was a pickup. Run a small generator, such as a Honda EU series in the bed of the truck. I have done it and have seen others, as well. You can run an armored cable from the bottom fridge vent along the belly pan to the hitch, to supply 120 vac from the generator in the bed.