DC Wiring for 12 V Panel

Hey Now Bob

Member
Jun 4, 2022
26
Memphis, TN
Hey now. I’ve got a new to me, 2018 Jayco Jay Sport 8SD. If the weather in Memphis gets below 100 this weekend, I’m going to install a 12 V panel with a USB, socket, voltmeter and unit switch. The PUP came prewired for a stereo, so I’m thinking I don’t have any wiring to run, just tap right into that power. There isn’t a stereo, so I’m betting the small draws from the panel would be less than what a stereo would have.

When I looked at the wiring though I was a bit confused. What I’m 90% sure is the power wire seems to loop back (meaning there is no end to the wire, wire caps or anything indicating the end of the line) and goes back into the kick panel that’s closed up. Is that standard for DC wiring? I haven’t started to pull on the wiring yet in hopes of a loose end coming through.

Thanks!
Bob
 

tombiasi

Super Active Member
Sep 1, 2012
6,773
Northwestern New Jersey
Hey now. I’ve got a new to me, 2018 Jayco Jay Sport 8SD. If the weather in Memphis gets below 100 this weekend, I’m going to install a 12 V panel with a USB, socket, voltmeter and unit switch. The PUP came prewired for a stereo, so I’m thinking I don’t have any wiring to run, just tap right into that power. There isn’t a stereo, so I’m betting the small draws from the panel would be less than what a stereo would have.

When I looked at the wiring though I was a bit confused. What I’m 90% sure is the power wire seems to loop back (meaning there is no end to the wire, wire caps or anything indicating the end of the line) and goes back into the kick panel that’s closed up. Is that standard for DC wiring? I haven’t started to pull on the wiring yet in hopes of a loose end coming through.

Thanks!
Bob
It would be nice if you could find the end.
 

Hey Now Bob

Member
Jun 4, 2022
26
Memphis, TN
Hey now. After further review….

The looped 12v wiring dives back behind a panel and supplies the outside entry light. I traced the cutout back and found the light and the water pump are on a 15 amp fuse. Nothing else is, so I’ll splice into the “loop” for the panel. I’m estimating the max pull on the panel to be 5 amp. With an led light on the outside that should leave just under 10 amp for the water pump. Fingers crossed.
 

Hey Now Bob

Member
Jun 4, 2022
26
Memphis, TN
After many hours...

I got the unit all wired up and bam. Blew a 15 amp fuse. Let's call that the yellow circuit. I went to look at the outside light, and it was on. Strange. Voltmeter gave me 12 v on the wiring to the panel. Strange. I then started pulling fuses. The 30 amp fuse was the one that turned off the outside light and power was no longer at the panel. Let's call that one the red circuit. But why did the yellow blow if it's on the red. I checked the ground, followed it under the pup, it looked good. I tried to find where the red and yellow may touch, but don't find anything until they dive into the power center.

I'm thinking this is a short somewhere, but where might that be?

It's about 98 outside, so I'm going to wait until this evening to pull all the power and disconnect the battery to run some continuity testing.

It's a new to me, 2018 Jayco Jay Sport SD8. WFCO Wf-8725 power center. Lucky for me, this is a very clear sticker and the circuits are printed with the fuse sizes, so I'm sure I'm within the specs there.

Any troubleshooting steps would be greatly appreciated!
 

Hey Now Bob

Member
Jun 4, 2022
26
Memphis, TN
Battery is connected. I checked the red + from the battery and it looks good under the frame. Also checked the bus bar ground and that looks solid. I get continuity when I check the positive splice and go direct to the bus bar. I also get continuity when I check the neutral splice to the bus bar. I disconnected the battery now, removed the wire nuts for the 2 circuits at the controller and I don’t get any continuity between the red circuit and the yellow. But slight between the neutral and the red. By slight I mean I regularly get a beep right when I touch the red wire coming out of the controller and the neutral splice.
 

SteveP

Super Active Member
May 21, 2015
2,649
If by neutral splice you mean the white wires for the 12VDC - return to the converter/battery, yes, when you connect the red to the white you have a completed circuit.
 

Hey Now Bob

Member
Jun 4, 2022
26
Memphis, TN
If by neutral splice you mean the white wires for the 12VDC - return to the converter/battery, yes, when you connect the red to the white you have a completed circuit.
Thanks Steve. Yes that is what I meant. But should I get consistent continuity when I do that? Seems weird it was beating just for a moment. Even had a second set of hands to make sure the multimeter connections were good.
 

Hey Now Bob

Member
Jun 4, 2022
26
Memphis, TN
Hey now---

So when things don't make sense, I access my original thinking. Though I followed the wiring diagram for the switch, looks like it may have been wrong and creating a short (I can't remember what they call it when you mis-wire a switch. 1/2 short?). By moving the positive to the brass connection (only after finding out the button of the switch pushed out if you applied enough mistaken force) things stopped to short. See the bogus-a** picture for their "wiring diagram". The top "+" was brass, so I've hooked into that and the switch now seems to have power (the light turns on and off!).
Wrong.png

I'm still a little perplexed about the circuit, fuse and the way this blows a fuse and stays hot. There is an inline fuse at 10 amp, so everything is protected. I still have some additional things to figure out, but this is getting better all the time...

Thanks for the comments and help. Hopefully the next post in a few days is a shot of everything working and plugged in and whatnot.

Then I can install that Weboost!

Peace,
Bob
 

SteveP

Super Active Member
May 21, 2015
2,649
Need some identifying info on this "switch." There is no need for both the + and - wires to pass through a switch unless it's lighted. With DC you can switch either the + or the - wire and achieve the same result.
 
Last edited:

SteveP

Super Active Member
May 21, 2015
2,649
But should I get consistent continuity when I do that?
If the converter contains any capacitors it could retain a little energy even with the battery and Shore Power disconnected. In which case I would expect it to beep once while the stored energy drains off. If you break connection and try again it should not beep.

I prefer to use a test light when checking continuity.
 

Michael J

Active Member
Aug 9, 2018
201
Michigan
If it's one of them USB/switch panels from Amazon the wiring can be a little strange I bought 2 on with a power port and one without but had problems with one of the switch not even working I left the negative off the switch as it makes too much light in the camper at night
 

SteveP

Super Active Member
May 21, 2015
2,649
Sorry about the side trip, back to basics.
Blew a 15 amp fuse. Let's call that the yellow circuit. I went to look at the outside light, and it was on. Strange. Voltmeter gave me 12 v on the wiring to the panel. Strange. I then started pulling fuses. The 30 amp fuse was the one that turned off the outside light and power was no longer at the panel. Let's call that one the red circuit.
The 30 amp fuse/red wire should be the battery circuit and pulling it should break connection between the fuse panel and the battery. If you were on Shore Power you still should have 12 VDC from the converter and previously active circuits should still be active.

Disconnect the power line from the Amazon panel and replace the fuse for the yellow wire. Turn on every thing in the camper, pull the yellow wire fuse and note what goes off.
 

Sandman51

Member
Jul 7, 2021
27
Athens, GA
After many hours...

I got the unit all wired up and bam. Blew a 15 amp fuse. Let's call that the yellow circuit. I went to look at the outside light, and it was on. Strange. Voltmeter gave me 12 v on the wiring to the panel. Strange. I then started pulling fuses. The 30 amp fuse was the one that turned off the outside light and power was no longer at the panel. Let's call that one the red circuit. But why did the yellow blow if it's on the red. I checked the ground, followed it under the pup, it looked good. I tried to find where the red and yellow may touch, but don't find anything until they dive into the power center.

I'm thinking this is a short somewhere, but where might that be?

It's about 98 outside, so I'm going to wait until this evening to pull all the power and disconnect the battery to run some continuity testing.

It's a new to me, 2018 Jayco Jay Sport SD8. WFCO Wf-8725 power center. Lucky for me, this is a very clear sticker and the circuits are printed with the fuse sizes, so I'm sure I'm within the specs there.

Any troubleshooting steps would be greatly appreciated!
Not that this is your situation, but...
I installed a 12 v panel that I got off eBay. It has USB, 12 v outlet, and a voltmeter. I hooked it up to the circuit with the outside step light and I, too, blew a fuse when I turned everything back on. I scratched my head for most of a day and somehow I finally figured out that the polarity of the USB port was not what was marked on the case. I think I figured it out with a multi-meter. So, I hooked + to - and - to + just for the USB port and everything worked fine when I turned the system make on. For that reason I now pay the extra money and buy 12 volt stuff from name dealers.
 

Firehawk068

Active Member
Mar 22, 2016
302
Hey Bob,
Just something to consider................A lot of Campers use "Black" wire for the positive + DC circuits, and "White" for the negative - DC circuits.
This is different than automotive DC wiring, and can cause confusion when wiring up 12-volt accessories inside a Camper.
Not sure if this is the case with yours, but just something to be aware of.
 

Hey Now Bob

Member
Jun 4, 2022
26
Memphis, TN
Another thought, are you talking about one of the buss bars in the breaker panel or do you have a buss bar outside the power panel?
Thanks Steve. There's a bar attached outside the Controller, all negatives go there (and they are white as @Firehawk068 suggested), and the bar is grounded to the frame. I haven't had a chance yet to get back out there to start going through the steps suggested by everyone. The demands of my fake life M-F/9-5, seem to interfere with what is really important.
 




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