No 12volt power when disconnected from shore power

[Camping Prouhets]

I have a 2016 28BHBE TT and have been having some electrical issues with the 12volt system. When the TT is connected to shore power everything works great but once I unplug from shore power there is no power to the camper at all. No lights, no refrigerator, no awning, ect. To date I have checked the fuses (good), replaced the 12 volt battery, replaced breakers, and replaced the power converter. Still nothing. I have put a volt meter to test the 12 volt power coming into the power center when unplugged and get a very low reading .5-.6 volts when the battery is fully charged, and once the camper is plugged in to shore power the voltage reads 13.6V. I am at the end of my troubleshooting list and the next step is to take it in for service.

Any ideas or help would be great!

Thanks

JP

[RetiredOne]

Originally Posted by Camping Prouhets

To date I have checked the fuses (good), replaced the 12 volt battery, replaced breakers, and replaced the power converter.

Did you check the main fuse up at the battery, and the reverse polarity fuses in the panel? If they are all good, maybe it's a bad ground problem, which is common. Slide under and make sure the main ground wire is making good contact with the frame. Many times, these corrode away.

[Marcm157]

X2 on the 30 amp fuse behind the battery. I have the same camper and mine is just before the power wire goes under the main camper body...

[Bob K]

Originally Posted by Camping Prouhets

I have put a volt meter to test the 12 volt power coming into the power center when unplugged and get a very low reading .5-.6 volts when the battery is fully charged

When you test at the power center, what wire are you testing for 12 volts and what are you checking as the ground?

...and once the camper is plugged in to shore power the voltage reads 13.6V.

That sounds like the proper voltage coming from the charge controller. Are you checking the same ground and what is it?

This would make me think there's a continuity problem on the 12v pos (+) wire or neg (-) wire coming from the battery. Here's what I would try & check next.

• Get some long extension wires so that you can use your voltmeter to do a continuity check on the positive and negative wires from the battery to the power center.
• Check the junction box. If it's anything like mine was, it's not even close to being environmentally sealed and might have lots of corrosion. Check for corrosion and loose wires.
  
• Check continuity on the positive and negative wires between the battery and the junction box.
• Check grounding screws. I replaced my corroded screws with stainless screws and a healthy dose of dielectric grease.
• Check all terminals. Jayco does an inexcusable job of crimping and protecting terminals from the elements. Mine were loose and corroded.
  

[Camping Prouhets]

I checked the fuses and they all look good and I am checking the voltage coming in from the battery where the probes are in the photo (White Battery Ground & Black Battery positive). I also checked the wiring behind the battery and it all looks good and all the connections seem to be tight.
When the camper is plugged in to shore power there is no charge going to the battery and i am not sure how to check the continuity from the battery to the power center.

[Bob K]

Originally Posted by Camping Prouhets

When the camper is plugged in to shore power there is no charge going to the battery.

That would further my suspicion that there's a continuity problem on the positive or negative wire running from the battery to the power distribution box. It would also lead me to believe that there's another connection somewhere in the power distribution area that ties in with the actual (+) and (-) 12v wires that come from the junction box at the front of the trailer. It explains why you're getting 13.6v at those two terminals in your picture while on shore power (ie. you're detecting the charge controller voltage) but that voltage is not getting passed to the battery (because of a bad connection on that circuit).

I would try:

• Determine if those two wires you're holding probes on run into other connections, equipment or switches on or behind the power distribution box.
• Or, determine if those two wires run unbroken up to the junction box where they tie in with your towing electrical cord somewhere near the front of the trailer.

If they run into something else behind your power distribution box, that switch or connector could be the fault. If they run unbroken up to the junction box at the front of the trailer, then your problem lies upstream from the power distribution box.

Here's an example. In my setup, multiple 12v negative wires are terminated at a buss bar screwed to the floor behind the power distribution box. Additionally, the heavy gauge 12v wires that are attached to the power distribution box are also tied in with other wires behind the box (red wire nut in this pic.) check there for loose connections.


To test continuity, get a long piece of wire. Connect one end to the positive battery terminal. Take the other end into the trailer. With your voltmeter on the ohm setting, touch one probe to the corresponding 12v positive terminal on the power distribution box and the other probe to the end of your long extension wire. You've just created a big loop, or circuit, that runs through your voltmeter. If you have good continuity (ie, the loop is unbroken), you should get a really low ohm reading. Repeat for the negative wire.

[Jim Davis]

There is one fuse that I'm not sure you have found. It is a master fuse for the battery and hard to see. From the positive terminal run your finger along the large red wire. At the frame will be a small black fuse holder (smaller than a postage stamp). Not only check it but look for corrosion.

[Camping Prouhets]

Thanks for all the help, there was a bad connection on the positive wire. Once I fixed this everything started working again!