12V DC Power Issues Unique

[Jayco and Boat Guy]

So I have been looking through threads on here to see if there's a solution to my problem and so far no luck.

The issues is my 12V DC system is not working off of the batteries. The 120V system works fine and is charging the batteries but at a reduced voltage from my volt meeting. My 12V DC system will work off of my truck , but not when unplugged and running from the batteries which is the weird part. I have full voltage on the batteries and it is holding a charge.

I checked all of the fuses in the power converter and they were intact. Checked the inline fuse and it was intact. Checked the 20A automatic fuse and it was also having no issues and showing a voltage, but there is no DC power at the converter in less it is connected to my truck.

I checked all of the grounding connections and everything is connected tight and not corroded. I traced all wires and see nothing that looks cut minus the wires that run behind the panels.

I have searched the for a battery shutoff switch and do not see one anywhere on the trailer.

I am wondering everyone's thoughts if it's maybe a power converter issue or a wiring issue from the manufacturer?

2019 Jayco 212QB travel trailer

[Thomson]

What is the voltage across the battery when plugged into 120v, and unplugged. Plugged in should be around 14v. Unplugged around 13v, It sounds more like dead batteries

[JimD]

Unplug and turn off the engine, What is the voltage reading right across the coach battery? If it is 12 volts or above but yet none of your 12 volt items work (even a battery as low as 12 volts will light a light bulb), there is a break in the circuit between the battery and the coach. This could be a bad ground connection to the frame (somewhat common) or a blown battery fuse near the battery (have heard that is common), or the battery cutoff switch (if present).

My guess at wire routing would be the battery ground cable would go to the frame fairly close to the battery and the +12 would get routed directly to the coach fuse panel.

The converter typically feeds its 12 volt output to the fuse panel area rather than all the way to the battery on a separate wire. The charging line from the truck probably has a feed directly to the battery. These are my best guesses.

Once you get this fixed you can then verify the battery charging by measuring directly across the battery with either the engine running or the rig plugged in. Should be above 14 volts when charging a depleted battery.

[Jayco and Boat Guy]

It is 12.45 on and the same off.

[Jayco and Boat Guy]

It's a consistent 12.45V and increases when plugged in slightly as it charges.

I checked all of the fuses and the in-line fuse near the battery, and the automatic fuse near the battery, all are intact and work properly.

I checked all of the grounding connections too and they are all tight. The only ones I found on the frame are on the j-box near the battery and near the rear of the frame coming down from the power converter/ fuse boxes. I will triple check them again, but the trailer is only a year old too so I've verified they are all tight.

I requested the wiring schematic from Jayco... but of course will probably not get it. I'm honestly wondering if it was wired incorrectly from the manufacturer.

[RetiredOne]

Originally Posted by Jayco and Boat Guy

It is 12.45 on and the same off.

Your converter isn't charging... it should jump up to the mid 13's when you plug into shore power.

A fully charged battery, at minimum, should be at least 12.6. Usually higher right after unplugging, close to 13.

Did you do a load test on the battery, to see where the voltage drops under load? If it's static at 12.4, right after you unplug, it sounds like it is a weak or bad battery.

[Thomson]

Jayco is pretty good about giving off files of wiring and piping diagrams. Just ask and give your email

[morleyz]

Your converter is probably a Progressive Dynamics model. Look up the installation and troubleshooting guides here:

https://www.progressivedyn.com/suppo...ooting-guides/

It's strange that it runs off your truck. I could be wrong, but I believe the 12V charge line from your truck just charges the battery, but the coach would essentially still run off the battery. Also, the converter should directly supply 12V when connected to shore power independent of the battery circuit. I suppose it's theoretically possible that there is a disconnect somewhere and the truck is wired past it, but that would be a poor design.

The 12V+ should be a solid wire from the auto-breaker to the converter. If you have 12V after the breaker, you should have 12V at the converter.

[JimD]

I have attached the charging chart for my converter. You should be seeing voltages higher than what you have mentioned.

[Jayco and Boat Guy]

Thanks for the continued insight. I contacted Jayco and they will not share the wiring diagrams because they are liability... So they are basically trying to force me to go to a shop.

I can't load test the battery with the trailer since it is not supplying power to the trailer.

I will continue to analyze it this week and wire trace to see what's going on.

Next idea is to try running a new wire from the battery to the power center to see if that will provide power to the trailer, or try and see why the truck is providing power but not the battery.

Keep the ideas coming!

[jeffmcpa]

Take the battery out of the trailer.
Take it to a auto parts store, or vehicle repair shop and have it load tested.

Then you will be able to possibly eliminate one thing.

[Jayco and Boat Guy]

Good call, I will try that. I assume if I plug my deep cycle boat battery into the trailer, that would be an additional test?

[Thomson]

[QUOTE=Jayco and Boat Guy;873228]Thanks for the continued insight. I contacted Jayco and they will not share the wiring diagrams because they are liability... So they are basically trying to force me to go to a shop.

Call them back. If you get somebody else they may send them to you. I have numerous wiring and piping diagrams for mine.

[Jayco and Boat Guy]

Got the battery load tested and it came back in good shape, just a lower charge.

Called Jayco back and they told me to pound sand on getting the wiring schematic. "While your trailer is under warranty we have a policy to not to give it to costumers...contact a dealer to have them give it to you..."

But they are pretty sure it's a bad converter as well.

[RetiredOne]

Originally Posted by Jayco and Boat Guy

But they are pretty sure it's a bad converter as well.

Sounds like it, since you don't get the higher jump in voltage when you plug into shore power. Good thing it looks like the battery wasn't hurt.

[Jayco and Boat Guy]

Right? And luckily they aren't too hard to swap out. Let's just hope when the new one comes in that is the issue.

More to come!

[JimD]

I had to replace my converter after only a year. It quit going into boost charge mode. I did some troubleshooting and contacted the converter manufacturer. It had a 2 year warranty so they sent me a new one and I returned the defective one. MUCH better than taking it back to the dealer and waiting for 6 weeks to get them to do the same thing. Has been working perfectly ever since.

How did I know it wasn't going into boost mode? I have a battery voltage gauge that is constantly displaying the battery voltage. I like keeping an eye on it. It will go into boost mode for a number of hours and then step down. A voltmeter display is your best friend especially if you dry camp a lot.

[Jayco and Boat Guy]

So I wanted to provide everyone an update.

The solution was incorrect wiring my the manufacturer (Jayco) on the assembly line or one of the previous owners altered the wiring in the junction box.

The battery was not connected to the converter at all. The truck was directly wired to the converter hence why the truck was providing power to the trailer in addition to the 110V.

Jayco will still not provide wiring diagrams for the 12V system so I was wondering if anyone had a schematic to rewire the junction box?

[Bob K]

Originally Posted by Jayco and Boat Guy

The solution was incorrect wiring my the manufacturer (Jayco) on the assembly line or one of the previous owners altered the wiring in the junction box. The battery was not connected to the converter at all. The truck was directly wired to the converter hence why the truck was providing power to the trailer in addition to the 110V.

That's what I suspected. The trailer pigtail 12V positive wire is wirenutted together with the 12V positive wire coming from the battery and the 12V positive wire that runs to the power distribution center. If you're getting DC power in the coach while the truck is plugged in but not when only on battery, that would lead me to believe that there's a problem in continuity on the 12V positive wire from the battery to its proper wirenut.

Is that what you found? Did you have to get the battery's 12V positive wire wrapped into the correct wirenut?

[omgjoz]

I am having this exact problem with my 2021 184BS Baja. Was wondering what I can do to fix myself, would save a long trip to the dealer plus waiting for them to fix and the long return trip home.