Pop up electrical problem. blown fuses to battery. Where to start?

[Diamond#1]

Hello I am new to RV site and just purchased a used 2008 Fleetwood pop up camper.  There seems to be a problem with the electrical and I do not know where to start looking for the solution. 

When I first purchased it it seemed to work fine but there was no battery hooked up just 120v.

I hooked up the pop up for the first time to both 120v and battery last weekend and after about 10 mins it started to smell a burning smell from the converter box inside the pop up and then a loud pop and the 30amp fuse at the battery literally blown.  It was so bad that it melted the whole fuse holder together still created a connection as the metal parts were fused together.  But luckily I was there and disconnected it from the battery quickly.  (Note the fuse on the converter box labeled battery 12v 30amp fuse was still good)
We finished the trip with just hooked up to the 120v and everything but the interior light and toilet worked so it wasn't too bad.   
Now that I am home here is what is happening.

1) When I hook up the battery 12v itself it works fine.  The interior lights, the toilet and the water pump.  Battery shows 12.65v

2) When I hook up the 120v to the camper with battery hooked up and check the voltage it goes up to slowly to reading 18v not sure if it would have gone up more as I was too afraid and unhooked it the 120v.

3)  I do see some sort of problem.  So without even the 120v plugged in, when I use the volt meter and touch the positive part of the battery terminal with one end of the meter and the other end of the volt meter to the positive part of the wire coming out of the trailer that supposed to be hooked up to the possible terminal of the battery, it shows a reading of 12.65v.  (Shouldn't it have a "0" reading?)

Please assist if possible to let me know where the simplest solution might be at.
Or could it be a bad converter?

I will bring it to a professional but wanted to make sure it was not a simple fix or something I can do before I do so. 
Thank you for any assistance. 

 

[Gizmo100]

Welcome to the forum Diamond,

Sorry your getting off to a rough start..I won't be much help but I'll get you started.

1) When I hook up the battery 12v itself it works fine.  The interior lights, the toilet and the water pump.  Battery shows 12.65v

This would tell me that with the battery everything is working fine..So that narrows down the problem area.

2) When I hook up the 120v to the camper with battery hooked up and check the voltage it goes up to slowly to reading 18v not sure if it would have gone up more as I was too afraid and unhooked it the 120v.

This is the part that concerns me...The converter also acts as a charger to the battery. And 18 volts is way too high.

3)  I do see some sort of problem.  So without even the 120v plugged in, when I use the volt meter and touch the positive part of the battery terminal with one end of the meter and the other end of the volt meter to the positive part of the wire coming out of the trailer that supposed to be hooked up to the possible terminal of the battery, it shows a reading of 12.65v.  (Shouldn't it have a "0" reading?)

If the Ground side of the battery is connected then you are completing the circuit..So 12 Volts would be present.

It appears your converter is working to power everything until you hook up a battery. I would start by leaving the battery dis-connected....Plug in the 120 and check the voltage at the cables ends. And report back

It may be a bad converter...BUT I AM NOT AN EXPERT ON THIS.

Smarter people than me will be along at some point today

 

[Gary RV_Wizard]

I'm inclined toward a bad converter/charger, for the reasons Gizmo gave.  An 18v charge voltage is way to high - should never exceed about 14.5v and usually more like 13.6v.  Can you see a brand name on the converter/charger or the panel it is in?

The fuse that blew was inline with the wire at the positive terminal of the battery? And that is in addition to another 30A fuse on the converter itself?  Was the inline fuse also 30A, or maybe more?  From your description, it sounds like the fuse holder had a lower amp capacity than the fuse that was in it. Either that or it was corroded and simply overheated before any fuse blew. A corroded wire connection acts like a resister and generates heat.

 

[Chakara]

  I agree - no amount of mis-wiring can make 18V DC.  Can't think of any other way for that to happen but a bad converter.

-Kyle

 

[Diamond#1]

Hello Gary, Gizmo and Kyle thank you for the info.

Gary,
The fuse that blew was a 30amp fuse that was inline with the positive battery terminal.  There was an additional 30A fuse on the converter itself that did not blow.

Gizmo100
The Ground side of the battery was connected (white wire to the "-")

But the problem seems to be the positive side.  I used the volt meter.  One side to the battery "+" and other side to the red wire and it shows 12.65v.  Is that normal or does it mean red wire or converter is grounded in some were it shouldn't be? 

 

[Gizmo100]

Gizmo100
The Ground side of the battery was connected (white wire to the "-")

But the problem seems to be the positive side.  I used the volt meter.  One side to the battery "+" and other side to the red wire and it shows 12.65v.  Is that normal or does it mean red wire or converter is grounded in some were it shouldn't be?

The ground wire off the battery is connected to the frame of the trailer, This is normal, as is your reading of 12.65 volts

This is not a concern.


What is a concern is the 18 volt reading feeding to the battery from the converter. At this point you could run your camper off the battery or disconnect the battery and plug into 120 volts.
If you can find your converter try and get the model number, Also some pictures you showing the connections to and from the converter.
Repairing the converter is not cost effective in most cases. So replacement is most likely the answer.

 

[Mark_K5LXP]

Make/model of the converter is the $64K question.  My '90's popup came with a very basic converter that was just a transformer and a rectifier and would put out over 16V, unloaded.  Put a battery or other load on it and it would drop down to 14V or so and down to 12V and change with everything turned on.  Whether 2008 models come with such crude converters I don't know.  Melting a fuseholder describes a scenario of overcurrent, and an underrated fuse holder (they should survive holding current and blowing whatever fuse they're rated for).  So at a minimum the fuseholder gets replaced with something proper and the battery/converter/charging circuits get a close review.

Mark B.
Albuquerque, NM

 

[Diamond#1]

Here are some images of the converter

 

[Lou Schneider]

Here's a link to the Owners manual for your Elixir converter.  It appears to be an electronically regulated converter and according to the output voltage vs. load chart on the last page, there's no way that converter should put out more than 13.5 volts, even unloaded.

https://www.fourwh.com/elixirpowerconverter.pdf

Pull the Reverse Current Protection fuse (the "Battery" 30 amp fuse on the right) and with the converter energized, measure the voltage from each empty fuse terminal to the power panel chassis or another negative 12 volt point.  One terminal will be the converter's output, the other will be the battery voltage.

You'll likely see more than 13.5 volts on the converter terminal which means the converter is toast, it's internal regulator has failed and it is putting out too much voltage.

My guess is the 30 amp fuse at the battery popped first because it may have had a corroded connection due to battery fumes that heated up and transferred heat to the fuse, making it pop faster than the same fuse located in the power panel.

3)  I do see some sort of problem.  So without even the 120v plugged in, when I use the volt meter and touch the positive part of the battery terminal with one end of the meter and the other end of the volt meter to the positive part of the wire coming out of the trailer that supposed to be hooked up to the possible terminal of the battery, it shows a reading of 12.65v.  (Shouldn't it have a "0" reading?)

No, what you're reading is correct.  When the positive wire is disconnected from the battery it falls to zero volts.  Your voltmeter is reading the difference between that and the 12.65 volts on the battery's positive terminal.

 

[John From Detroit]

Is it possible you put  the battery in Backwards?  YOu've done a fairly good job of desribing what can hapen with SOME converters if you do that.

NOTE: Not the only possible cause of those symptoms but #1 on the hit parade for sure.

ANother possible cause is a bad converter.. but I'm inclined to discount that.