16' Series Potential short circuit issue

[Desert Rat]

Good afternoon all. First post to this forum, having only had our 2008 Expanda 16.49.3 for 2 months.

Just had the Expanda in for a general 10k service and was advised that we needed a new deep cycle battery. Not wanting to accept their generic offering, I opted to arrange one myself after return of the van.

Got a Bosch 120ah at a reasonable price and fitted the same yesterday afternoon.

I have just tried charging the battery from our mains supply and note that when I turn the battery switch to the on position (which I believe takes it out of the isolation mode), it blows the battery fuse. I have tried disconnecting the mains power and turning the battery switch on, and it still blows the fuse.

My belief is that there is probably a short circuit somewhere.

Question: any learned people or auto sparkies that can give me a starting point on where I should start looking for the problem? Or should I just book it into my nearest auto electrician?

Thanks in advance.

Simon

 

[MDS69]

First up welcome to the forum.
Is the polarity of the battery correct. Due to different cases and terminal layous it may be connected wrong.

 

[jvp]

Check wiring polarity on aux battery.
Jayco use US colors for trailers.
White Neg.
Black Pos.
Could be simple fix otherwise call the auto elec.
jvp

 

[jvp]

What size battery fuse blows & is it the one at the Cetec or at the aux. battery.
Maybe too small.
Check specs. before going bigger though.
jvp

 

[Bellbirdweb]

@jvp size of the battery would not be relevant.

If the battery is dead flat, it could
be pulling more current than the capacity of the battery fuse, but if it's that flat, it's probably cactus anyhow, even if a deep cycle.

I'd go with the original suggestion of reversed polarity.

 

[Desert Rat]

First up welcome to the forum.
Is the polarity of the battery correct. Due to different cases and terminal layous it may be connected wrong.

It's funny you should ask what most might think is a fairly basic question. I say it's funny as when I went to connect up the new battery, there were three black leads taped together and three white leads taped together. Not a red lead in sight! I have assumed that black would always be black (and therefore -ive), and that the White ones must be the red (and therefore +ive).

Is there a way of checking?

Many thanks.

 

[Hubble80]

I have some fault finding that you can do to eliminate which circuit is causing your fault but it could go through A LOT of fuses.

Try disconnecting the negative of the battery and turn the switch on when the van is connected to 240V, does the fuse blow?
Reconnect the battery and pull all of the fuses out of the Setec except the battery fuse and try to turn it on, does it still blow?
If the fuse does not blow with the two steps above try replacing the individual circuit fuses one by one to see if a particular circuit is blowing the fuse. If you find one that is blowing the fuse you can try putting all the fuse back in except that one, then you need to trace that circuit out. If this is a bit out of your confidence level, the auto electrician should be able to sort it for you.

Ensure that the fuse ratings are correct also. From memory the Battery fuse should be 30A (Red) and the individual ones 10A (Green)

 

[Desert Rat]

Check wiring polarity on aux battery.
Jayco use US colors for trailers.
White Neg.
Black Pos.
Could be simple fix otherwise call the auto elec.
jvp

Many thanks JVP and all.

Changed the wires over and no blown fuse, and electrics working as they should.

I was unaware that Jayco used US wiring colours. It just seems counter-intuitive to wire up a black wire to a red terminal!

You guys have probably just saved me hundreds in auto sparky costs! Hope I can return the favour at some stage.

 

[Bellbirdweb]

It's funny you should ask what most might think is a fairly basic question. I say it's funny as when I went to connect up the new battery, there were three black leads taped together and three white leads taped together. Not a red lead in sight! I have assumed that black would always be black (and therefore -ive), and that the White ones must be the red (and therefore +ive).

Is there a way of checking?

Many thanks.

Black = +ve White = -ve, if you have black on the negative that will be the issue.

 

[MDS69]

It's funny you should ask what most might think is a fairly basic question. I say it's funny as when I went to connect up the new battery, there were three black leads taped together and three white leads taped together. Not a red lead in sight! I have assumed that black would always be black (and therefore -ive), and that the White ones must be the red (and therefore +ive).

Is there a way of checking?

Many thanks.

Not having had my Expanda long I have yet had to play around with it much so I don't know if the 12V is bonded to the chassis of the van. If it is you could (with the battery disconnected) try and use a multi meter on ohms and see if there is continuity between the black cable and the chassis or the white cable and the chassis. Alternatively you could open up on of the 12V outlets in the van and check the markings and polarity there.

 

[Bellbirdweb]

Many thanks JVP and all.

Changed the wires over and no blown fuse, and electrics working as they should.

I was unaware that Jayco used US wiring colours. It just seems counter-intuitive to wire up a black wire to a red terminal!

You guys have probably just saved me hundreds in auto sparky costs! Hope I can return the favour at some stage.

Had to be it. Glad it worked out !

 

[Drover]

White/ Black is a bloody pain all right, I instinctively go black NEG and since I have done a few mods on my rig using the Red/Black combo I have got into the habit of tagging wire connections as I found some original Red/Black combo's to go with the White/Black.
But each time I do something I use my multi meter to make sure, especially as I found some really crappy originally.