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$bill · 10-05-2009, 06:19 PM

I have just purchased a 73 Overlander. The converter was working fine on friday, the lights, radio and Jack were working (when it was plugged in). Went back saturday and the plug-ins and AC would work, but had no lights, jack or radio. When I plug it in I can hear the Hum of the univolt. When hook it to a battery it blows a fuse. Any help will be greatly appreciated. I am planning on taking it out this weekend.

Thaks, Bill

Lumatic · 10-05-2009, 06:35 PM

Does the same fuse blow repeatedly? What circuit is it? Suspect a dead short first.

$bill · 10-05-2009, 06:38 PM

It is the large fuse mounted in front of the univolt. It blows when you hook up the battery.

Lumatic · 10-05-2009, 06:43 PM

If that fuse is a larger glass fuse than the 20 amp fuses for the other 4 trailer circuits it should be a 40 amp glass fuse for the battery/univolt supply. They are hard to find. If you put in a smaller fuse it will blow. You can also put in a 40 amp resetting circuit breaker that fits into the fuse slot. But that kind of defeats the purpose of a fuse. Check the amps and size of the fuse you are talking about. Photos will help.

Lumatic · 10-05-2009, 06:48 PM

Is this what your Univolt looks like? This is my 71. On my 71 the 40 amp fuses are the same size as the 20 amps and are the top 2 fuses on the left and right. The funny looking fuse is the 40 amp resetting circuit breaker.

$bill · 10-05-2009, 07:43 PM

Mine has blown the 40 amp Battery fuse (Blue Wire) in the top left corner of the univolt once. It has blown the 40 amp ground fuse (black wire) from the battery twice. It blows them when you hook it up to a battery. I hooked it up about 30 minutes ago to AC and it did notblw a fuse and you could hear the Hum of the univolt. It still had nothing that works on 12v.

Lumatic · 10-05-2009, 08:18 PM

Any chance you reversed the polarity of the cables from the Univolt to the battery? When you last hooked it up and did not blow a fuse did you check you had 12v going into and coming out of the 20 amp fuses? Are you sure the 40 amp fuses are not a lower amperage? If the battery is disconnected and you are hooked into shore power does the Univolt put out around 13 volts and do you have any 12v coming out of the Univolt? Did you check the main ground to the frame is good? Also check the polarity of your shore power.

StingrayL82 · 10-05-2009, 08:54 PM

Double check those fuse ratings...The trailer battery red fuse is rated AGU 50 amp, not 40. The car battery blue fuse is rated AGU 40 amp.

on edit: Just took a pic, for reference and, yes, I am becoming a UniVolt collector

. The disassembled UniVolt on the right is from a 1971. The main one pictured is from a 1970:

Lumatic · 10-05-2009, 09:09 PM

Note my Univolt is different from Stingrays. The OEM battery fuse in mine is 40 amps. There is also a different configuration which uses physically much larger fuses for the battery and auto battery. Here is the link .

http://www.airforums.com/forums/atta...5&d=1221090856

This is a univolt fuse panel wired to a Intellipower upgrade

There may be other Univolt variations.

StingrayL82 · 10-05-2009, 09:39 PM

Interesting, indeed. It would appear that there were several different variations of UniVolt. I suspect that the picture of the UniVolt I provided is actually a replacement unit, found on 1972 and later Airstreams. Maybe 1971 is the year where they used both the earlier type, as pictured in Lumatic's earlier post (and the one disassembled in my pic, on the right) and the one I have pictured....I've seen both types in 71 models. Maybe the length dictated which UniVolt model was used?

Inland RV Center, In · 10-05-2009, 09:51 PM

Quote:

Originally Posted by Lumatic

Note my Univolt is different from Stingrays. The OEM battery fuse in mine is 40 amps. There is also a different configuration which uses physically much larger fuses for the battery and auto battery. Here is the link .

http://www.airforums.com/forums/atta...5&d=1221090856

This is a univolt fuse panel wired to a Intellipower upgrade

There may be other Univolt variations.

The fuse panel from your original Univolt is now being used with your charging system.

Andy

Lumatic · 10-05-2009, 10:04 PM

Quote:

Originally Posted by Inland RV Center, In

The fuse panel from your original Univolt is now being used with your charging system.

Andy

The photo in my post above is from the forums archives, not mine. but I did the same thing saving the Univolt case. And, yes the Univolt fuse panel is hooked in to my Intellipower and other than the fuse panel it is gutted. I call this combination my Unintellipower

Inland RV Center, In · 10-05-2009, 10:11 PM

Quote:

Originally Posted by Lumatic

The photo in my post above is from the forums archives, not mine. but I did the same thing saving the Univolt case. And, yes the Univolt fuse panel is hooked in to my Intellipower and other than the fuse panel it is gutted. I call this combination my Unintellipower

Sounds good to me.

Of course Nuetergendertellipower is a good name too, but much to long of a word.

Andy

$bill · 10-06-2009, 01:21 PM

Quote:

Originally Posted by Lumatic

Any chance you reversed the polarity of the cables from the Univolt to the battery? When you last hooked it up and did not blow a fuse did you check you had 12v going into and coming out of the 20 amp fuses? Are you sure the 40 amp fuses are not a lower amperage? If the battery is disconnected and you are hooked into shore power does the Univolt put out around 13 volts and do you have any 12v coming out of the Univolt? Did you check the main ground to the frame is good? Also check the polarity of your shore power.

The Univolt in mine is like the one in the picture posted by StingrayL82. I am going to try to remove it this afternoon when I get home from work. I will have to round up a tester to check the voltage going to the trailer, when it is plugged in. I did notice something last night, when it is plugged in the jack tries to run. It is kind of like it is running off a battery that is weak.
All of this worked fine on friday, but when I got there saturday morning to pick it up nothing on the 12v side would work.

Jim & Susan · 10-06-2009, 02:27 PM

Quote:

Originally Posted by StingrayL82

Double check those fuse ratings...The trailer battery red fuse is rated AGU 50 amp, not 40. The car battery blue fuse is rated AGU 40 amp.

on edit: Just took a pic, for reference and, yes, I am becoming a UniVolt collector

. The disassembled UniVolt on the right is from a 1971. The main one pictured is from a 1970:

Mine is fused like you said, 50/50/40 amp. I have a 50 amp on the positive AND the negative legs going to the trailer battery. A 40 amp on the blue wire from the car battery.

$Bill, look at the front cover on the Univolt (the cover over the fuse panel). If you have a 45 amp model Univolt, you probably need to step up to 50/50/40 amp fuses. Also, the amperage rating on for each fuse is printed underneath each fuse holder on mine, FWIW.

Stingray, I have another Univolt to add to collection if you want it. It's replacement should be here tomorrow. Just don't ask me to drive back to San Angelo to deliver it.

Jim

$bill · 10-06-2009, 03:50 PM

Quote:

Originally Posted by Jim & Susan

Mine is fused like you said, 50/50/40 amp. I have a 50 amp on the positive AND the negative legs going to the trailer battery. A 40 amp on the blue wire from the car battery.

$Bill, look at the front cover on the Univolt (the cover over the fuse panel). If you have a 45 amp model Univolt, you probably need to step up to 50/50/40 amp fuses. Also, the amperage rating on for each fuse is printed underneath each fuse holder on mine, FWIW.

Stingray, I have another Univolt to add to collection if you want it. It's replacement should be here tomorrow. Just don't ask me to drive back to San Angelo to deliver it.

Jim

It is the 45 amp unit. It uses a 40 amp on the blue battery wire. It uses a 50 amp fuse on the red trailer wire. I am not sure what it is supposed to have on the black Ground wire, it is not marked.

Jim & Susan · 10-06-2009, 04:06 PM

I can provide a couple of pictures if you need them. Just let me know....

I'm not sure if it's original, but the negative cable to the trailer battery also had a 50 amp fuse. Are you still having problems? What is working and what isn't? I have a thread that describes what all of the these wires power, if you need it. I'll go find the posts and get back in a few.

Jim

$bill · 10-06-2009, 04:12 PM

Quote:

Originally Posted by Jim & Susan

I can provide a couple of pictures if you need them. Just let me know....

I'm not sure if it's original, but the negative cable to the trailer battery also had a 50 amp fuse. Are you still having problems? What is working and what isn't? I have a thread that describes what all of the these wires power, if you need it. I'll go find the posts and get back in a few.

Jim

Only the plugins and AC are working. The lights , radio and jack have stopped working. When you hook a battey up it blows a fuse. When hooked to 110V only 110V stuff is working.

Jim & Susan · 10-06-2009, 04:22 PM

Take a look at this thread beginning at post 360: http://www.airforums.com/forums/f226...tml#post326154

That will give you some idea how the 12 volt DC and 110 volt AC is wired. Your trailer may be a little different, but probably not by much.

Jim

Jim & Susan · 10-06-2009, 04:28 PM

Quote:

Originally Posted by $bill

Only the plugins and AC are working. The lights , radio and jack have stopped working. When you hook a battey up it blows a fuse. When hooked to 110V only 110V stuff is working.

So it sounds like all of your 110v is working properly, right?

You are having problems with the 12 volt stuff (only), right? The fuse only blows when you hook up the battery to the Univolt? In other words, when the battery is disconnected, all of the 12 volt stuff works? No blown fuses?

Jim