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-   -   Univolt Configuration (http://www.airforums.com/forums/f37/univolt-configuration-715.html)

rslaymaker 06-13-2002 06:24 PM

Univolt Configuration
 
All I have is questions...

Is there a place that I can find a diagram of how my 1965 Safari's univolt is configured? This electric stuff is driving me mad!

:confused:

FrankR 06-13-2002 07:21 PM

Univolt connections
 
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The univolt has but one way to be connected...... This device is a battery charger or substitute for a battery. It is connected to the common battery connections. One wire from univolt will be positive to be connected to the same connection point the battery positive is connected. Same idea for the negative connections. This device will only make dc when shore or house power is connected. While traveling down the hiway, a converter just does nothing.

FrankR 06-13-2002 07:24 PM

More converter wiring
 
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My portable Palace is a 1979 Land Yacht..
This wiring can work for you.....

FrankR 06-13-2002 07:30 PM

Interior wiring
 
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AS wiring plan..........

FrankR 06-13-2002 07:33 PM

12 Exterior wiring
 
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AS plan.......

rslaymaker 06-14-2002 07:53 PM

Idaho Rules
 
That will keep me motivated... Thank you! Thank you! Thank you! It looks like I have some directions and maybe I can better understand things.

pap 03-26-2003 11:01 AM

No battery aboard
 
What if any effect on uni-volt (operation of it and damage to it) unit does not having a battery make.

Also if by chance the positive and negative battery cables come into contact with each other, while there is no battery aboard, and the uni-volt is activated (plugged in) and shore power is applied...what happens??

montanaandy 03-26-2003 11:12 AM

Univolt - Removal & Replacement
 
Frank - this is a bit off topic but I thought that I would ask you since you have the same model year/trailer that I have - how difficult is it to access & remove the Univolt in a 79'? I have an Intellipower w/Charge Wizard that I would like to install this Spring but I am not certain how to access and remove the Univolt. Any suggestions? Thanks, Montanaandy

FrankR 03-26-2003 11:37 AM

Univolt... Battery or not
 
It has been my experience with most converters, that a battery is NOT required . Converters can be used to power any 12volt rv device that does not exceed the maximine amps available from the converter. Most converters are rated at about 50 amps. My old converter easily powers the furnace. The furnace is the highest load in our Airstream. The converter is a large step down transformer. The converter reduces house power from 120volts to 12volts dc. The dc voltage is a pulsating dc voltage, not the real clean dc from a battery. Some folks use a battery to smooth the rippling dc voltage while using some small dc tv sets and some radios. The univolt converter is not quiet, but is very tough. Adding a seperate switch just for the converter is a very good idea.....

pap 03-26-2003 12:00 PM

Why a switch?
 
Thanks Frank,
I was surprised that the univolt was not hard wired but instead had a plug in cord. It made me think that there might be a reason to unplug it when not in use. Your suggestion of a switch leads me in that same direction.

So I must ask why?
Is there an overheating (fire) concern if left on (plugged in)?
Transforming down of current generates heat doesn't it? I wonder what is the cooling system within the univolt?
Would it be wise to try to add one of those computer mini fans?

My univolt is at the bottom of a closet in the rear bath (a dumb location in my opinion) That closet could well be stuffed with towels and etc.

or do you think the life of the univolt would be shortened by constant being on?

or does leaving the univolt plugged have some effect on the battery life and performance? If so I guess a battery interrupt switch could be placed between the univolt & battery ? would that be any benefit?
Obviously the battery is not part of the circuit since the thing works without the battery.

FrankR 03-26-2003 12:18 PM

Converters use
 
Converters are a very useful device. Some folks have used a converter for years with out a battery. It is very necessary to have the converter mounted in a place that affords air to circulate around unit. I have never known of any fire caused by a converter. Usually if the load or unit heat rises enough, the internal fuse will open. The univolt is repairable.
A converter switch is used mostly for stopping unit hummmmmm or when used with a battery, to stop charging the battery. The univolt is a good battery charger. So good in fact, that it wants to keep on charging the battery when no charge is required. The converter will charge a new battery until all water/acid is boiled out or evaporated away. These are tough electric units. Batterys require some monitoring and care. A new battery can be destroyed in about 10-12 time total voltage drawdown to less that 10 volts. A digital voltmeter is a battery's best friend....

Creampuff 03-26-2003 09:09 PM

Repairing a Univolt
 
Frank :
My Univolt Model 35 is apart on the bench as I was getting no output from it.My electrician friend tested it and tracked the problem to what appears to be a large resistor (CSR or SCR ??) .He hasn't been able to find replacement part.
Any ideas?
I went camping last weekend without it and found the only way I could get the 12v system to work was to stay hooked up to the tow veh.and keep the ign.switch on accessory.That was interesting!!

Pick 03-27-2003 06:16 AM

Charging rate?
 
I believe my UNivolt is rated at 40 amps. Does the unit start to charge the battery at 40 amps, or is the charging rate lower? I have read that other converters charge at a much lower rate, somewhere around 5 amps, and it is recommended to take a 15 amp charger, while boondocking. There was a nice 15 amp charger hidden in one of my compartments when I bought the trailer.

FrankR 03-27-2003 11:35 AM

New converter location.
 
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New aluminium box shop fabricated for converter mounted thru floor. Location keeps unit kool...

FrankR 03-27-2003 11:39 AM

Battery switch
 
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Great switch to allow use of converter without charging the battery.

ALANSD 03-27-2003 11:48 AM

my Airstream has the simple blade disconnect switches on the batteries to prevent charging when you want to. Unfortunately I didn't understand some of this when I bought my rig, and left it plugged in too often, overcharging the batteries. One works ok now, the other is a goner.

FrankR 03-27-2003 11:49 AM

My electrical changes
 
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I'm old and like things to be easy. So I made a few changes. The fuses and those problems are gone, replaced with aircraft circuit breakers. Converter located into floor for cooling and more useable floor space. Battery switch for opportunity charging selected battery or batteries, or no charge with use of converter. New 120 vac recepticle and switch for control of converter. Next will be a couple digital dc and ac voltage meters....... Ya know the easy kind..........

pap 03-27-2003 11:58 AM

Battery cut-off switches
 
Frank you are multi talented.
I think I saw that red switch in the control room of the command center in the movie China Syndrome.:D

BTW when installing a cutoff on the battery, do you need to break both negative and positive cables or just one of them?
I would guess the negative??? Please advise.

Also if I wanted a remotely located battery cutoff switch, say 6-8 feet away from battery, how big a cable and where to get such a switch?

I would use a blade at the battery but would prefer some sort of toggle at a remote location.

Whach ya think?

Oh and one more dumb question;
If a converter is a step-down transformer, is an inverter a step-up transformer?? Which generates the most heat?

FrankR 03-27-2003 12:28 PM

Electric stuff or how to...
 
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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.
Back to twisting wires. Most wiring requires only disconnecting the positive lead using dc current.
Remotely controlling a switch can have many choises. The choises are, to relocate a heavy duty switch and some large conductors ro use a heavy duty constant relay or a latching relay. The costs are all about the same. There are some really good aircraft breakers and relays or Ebay. To locate a battery switch as shown, would require some number 6 MTW [machine tool wire], red is a nice color for a positive cable, and some terminal ends of the correct size. The number 6 awg will handle up to 80 amps easily to and from switch. Wire is available from many sources as Home Depot, electrical supply stores, big rig truck shops, and any good electrician. This wire is very common. Battery switches are procured from any RV or boat supply or Ebay. I chose to locate switch close to batterys to avoid long wire runs. I am NOT a big fan of open blade switches. They can make a great spark and fire show.
Both the convertersand inverters use big transformers. The converter is a step down transformer and the inverter is a step up transformer.

Creampuff 03-27-2003 03:02 PM

Hey Frank:
You must have missed my earlier question post on the Univolt repair.
My research has lead me to believe it's a silicone coated rectifier I need.
Comments please!


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