Electrical short

[gordy4248]

I have a 2009 25' Flying Cloud. Tried to install new batteries. When I try to make the connection, I get a big flash, and blow both 30 amp fuses under the bed. Also tried w/ battery pack, same thing. Yes the polarity is correct. Need some ideas. Thanks!! Gordy

[cwf]

Gordy... Need to tell us why the batteries failed... Is his a new problem?

[richinny]

are these 6v or 12v batteries?
did you check along the positive cable for the cable touching some metal?
are the batteries charged?

[garry]

Not much info to go on.

1 or 2 batteries?
6V or 12V

Not long ago some one posted they bought 2 new 12V batteries and when they tried to hook them up they were really 6V.

[dwightdi]

Get an ohmmeter and find where the short is.

[gordy4248]

The original batteries are 6 yrs. old, and planning a trip, don't want any problems. Both new batteries are fully charged. There are no bare wires touching anything. I am wondering if there might be a relay stuck, or maybe a problem w/ the converter. (blows both 30 amp fuses when the terminal is touched to the post) When I try to connect the terminal to the battery, the much more than normal flash occurs.(like all electric devises are turned on) I am very familiar with the 6 - 12 volt systems, as I have been an auto mechanic for 37 years. What I would like to know, has anyone else had a similar problem with their Airstream. Just looking for a place to start. Thanks!! Gordy

[Al and Missy]

To answer your question, I have not had that problem, but.....

It is hard to imagine that this problem appeared after simply replacing the batteries. What do the 30A fuses feed? I'm guessing one is in line with the battery and the other is in line with the converter. Leave the battery disconnected. Replace the fuses and plug in the shore power. Does everything running from 12V work normally in the trailer? Try just some lights first. If not, perhaps the converter has failed and was shorting out the batteries. Try the tongue jack. Maybe the cable is pinched somewhere. Measure the voltage at the battery cables. Is the polarity correct? The voltage? Other than a failed converter or reversed polarity, I can't think of anything.

Al

[gordy4248]

Al: Thank you for your info. With the bat unhooked, and connected to shoreline, the fuses do not blow. I leave shoreline connected, both 30 amp fuses connected, battery disconnected, fuses do not blow, nothing works. ( lights, ect.) Shoreline connected, battery connected, both 30 amp fuses removed, everything works. Shoreline disconnected, battery connected, fuses removed, everything works except air con.Touched fuse panel spades with good 30 amp fuse, and I get a heavy arc. I hope this makes sense. Thanks again!! Gordy

[gordy4248]

If the inverter/converter fails, what are the simtoms? Gordy

[garry]

You can meter for a short at the 30 amp fuses one side goes to the load and one side comes from the DC distribution panel.
Or go to the DC distribution block you will have two main 12V INPUTS one set from the battery and one set from the converter. From there you can meter for a short coming into the panel or going out.

Normally when the converter fails the batteries go dead since it is the function of the converter to keep the batteries charged and supply +12V when on shore power.

[TG Twinkie]

Where are these 30 amp fuses located?
You stated: shoreline disconnected, fuses removed, battery connected. "Everything Works".
That tells me the wiring is good from the battery(s) to the fuse panel.
If everything works when on battery. And everything works when on shore power without the fuses. Then why the fuses?
I am still leaning toward a reverse polarity situation. And would double check the wiring a wire colors. To make sure everything is of the correct polarity.



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[Al and Missy]

Sounds to me like the converter output is shorted. This is one of several possible failures. There is no one answer to your question of symptoms of converter failure.

"With the bat unhooked, and connected to shoreline, the fuses do not blow. I leave shoreline connected, both 30 amp fuses connected, battery disconnected, fuses do not blow, nothing works. ( lights, ect.)." This is not good. If the converter were working, everything that runs off 12 volts should work.

"Shoreline disconnected, battery connected, fuses removed, everything works except air conditioner". This is normal and indicates that the battery wiring is correct and the battery(ies) are supplying power to the distribution panel.

If you can do this, a final test would be to disconnect the converter output and measure the voltage at that point. The best way would be to disconnect the (probably) red wire from the plus terminal of the converter. With the battery connected and both fuses in, everything should be OK. BE VERY CAREFUL WITH THE DISCONNECTED WIRE. IT IS CONNECTED TO THE BATTERY. You should measure positive 12 volts (from the battery) between the wire and ground. If you successfully complete this test, it is probable that your converter is shorted.

The only strange thing is when both fuses removed and shore power and battery connected, everything works. Do you have an inverter? What kind of store switch do you have? Older trailers have a mechanical rotary switch. Newer trailers have a pushbutton that controls a relay. Either a disconnect relay or an inverter could play into this problem.

Al

[gordy4248]

You sound like you have a few years of elec. behind you. Real nice when we ask a question, and someone only talks about the exact problem, instead of the usual boloney. Might you know where the inverter is located, an maybe the shape.? Thanks!! Gordy

[lsbrodsky]

Your inverter is going to be underneath the bed near the front wall, just about in the middle of the trailer. It is rectangular, mounted to the plywood bed support. It cannot be mistaken for any other device.
Larry

[TG Twinkie]

It is a converter, not an inverter. Fuses only protect what is downstream not upstream.
I would pull all of the fuses from the fuse block. Install the 30 amp and see what happens. Then replace one fuse at a time. Or use an ohm meter to locate the cause.


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[Al and Missy]

TG Twinkie: if the converter output is shorted, it is downstream from the battery and will blow fuses in series with either.

Gordy: your trailer definitely has a converter and may have an inverter. The converter converts shore power to 12volts to operate almost everything in the trailer and charge the batteries. An inverter, if you have one, takes 12 volts from the batteries and creates 110 volts AC to operate things that run on AC when shore power is not available.

Your converter may be under the bed, sofa, or dinette. The converter proper is a metal box about 10 inches by 4 inches x 3 inches. It may be part of a larger assembly (the power center) which includes the DC fuse panel.

Al

[tsunami]

Is the converter a 30 or 50 amp unit? I ask because I have replaced my good/functioning 30 amp parallax unit and would be willing to donate it if someone wants it. I also replaced the 12 volt fuse panel and it's included as part of the package..

[Al and Missy]

Gordy
You may find it helpful to read Section G of your manual. If you don't have one, you can download one from Airstream's web site. Manuals have their own tab under the "Service" tab on the home page.

Al