Both USB ports next to bed receiving low voltage

[Michael.Brock]

Our trailer is a 2023 Norther Spirit 2145rbx we bought used late last year. There is a two-port USB outlet on each side of the bed. These worked when we first got the trailer and there is a blue light on the panel which indicates it is receiving power. Some time during our last trip both outlets stopped working and the blue light now does not light. I pulled a panel in the basement and checked the voltage and the 12v USB outlet is only receiving 1.6v I disconnected the usb outlet itself to verify that there is no load in the outlet. I pulled and checked all of the fuses in the converter panel and checked all of the breakers and all of them look good. Any suggestions for the next thing to troubleshoot?

 

[NoviBill]

I am a bit confused by your explanation. USB Ports are 5 volt DC, the lights and most of your trailer is 12 volts DC from the battery or converter (if you are plugged in). So the power line to the USB adapter should be 12 volts. If you check the power on the USB port it should be 5 volts.

Are you running off of battery or plugged in?
If battery, what is the voltage at the battery? (12-14 volts is normal)
If plugged in, what is the voltage at the converter output? (12-14 volts is normal)
*be careful if you are plugged in to 110 volts AC, the input to the converter is 110VAC and can kill you.
Check the voltage at the 12 volt fuses (should all read same as battery/converter)?
If those voltages are fine, than it's between the fuse and the USB adapter port.

 

[Michael.Brock]

"So the power line to the USB adapter should be 12 volts. If you check the power on the USB port it should be 5 volts."

Yes. The voltage to the USB adapter should be 12v and is only 1.6v.

This is while on battery. The battery voltage is 13.5v

 

[NoviBill]

Voltage at each 12v fuse? Sounds like a lose/broken wire...

 

[Michael.Brock]

Voltage at each 12v fuse? Sounds like a lose/broken wire..

That is now the next troubleshooting step following your suggestion. I'm hoping to get back out to the trailer tomorrow to check on it. I tested all of the fuses but didn't check voltages.

 

[tomupnorth]

I'm new to my own TT and don't know how these particular USB outlets operate, but since my own USB outlets appear to be in close proximity to 120VAC outlets, maybe they accept 120VAC as input voltage? Does anyone here have a pic or specs of the dual USB outlet FR uses?

EDIT: OK mine looks like this one and so appears to be 12VDC input (black/red wires, not meant for a box as AC would require). Most likely it is connected to the fuse labelled Interior Lights, and if all the interior lights work then I'd guess wire nuts having come-apart somewhere inside the bed cabinets:

 

[Chuck_S]

120vAC outlets with USB charge ports are common as grass. If the USB ports are on the same face plate they're probably 120vAC powered. If separate a glance at the wire colors powering them should indicate the voltage. Red and White wires are standard RV 12vDC wire colors.

-- Chuck

 

[Michael.Brock]

The USB ports are separate from the 120v outlet (but it is nearby). Wires to it are red/white. They look like these:

https://www.amazon.com/VMDLKB-Dual-Port-Charging-Trailer-Motorhome/dp/B0DG8KB6YR/

The interior lighting works fine. Tracking down where the wiring nuts might be in the run from the front of the trailer to the panel seems daunting given how hard it is to access anything.

I find it odd that there is 1.6v to the usb port. I would think that if it were a wirenut issue it would 0v.

 

[tomupnorth]

I find it odd that there is 1.6v to the usb port. I would think that if it were a wirenut issue it would 0v.

Agreed but maybe one of the Plus or Minus is connected by a single strand.

As you've pulled the USB panel already, were you able to see inside? I'd remove any/all openings around the bed and investigate with a flashlight.

 

[NoviBill]

For the stray "1.6 volts", it is possible this is noise on the volt meter. Does your meter have a battery test mode? That adds a small resistance and might read zero.

 

[Michael.Brock]

I didn't pull the usb port itself but rather the panel behind it. I pulled the fuses and measured the voltage across each one and got 12v on all.

The volt meter measures 0v on open circuits.

 

[hamrover]

I didn't pull the usb port itself but rather the panel behind it. I pulled the fuses and measured the voltage across each one and got 12v on all.

The volt meter measures 0v on open circuits.

This might be a silly question, but where do those two white wires go to that are just hanging out not connected to anything? Do they measure any voltage on them?

 

[Michael.Brock]

Those were connected with crimped wire nuts to the usb port leads. I measured 1.6v at the bare wire in the nuts then cut the connection to check that there wasn't a load in the port that was the cause of the low voltage. So those wires are the power to the port.

 

[Aussieguy]

a) check battery voltage and make sure the battery disconnect switch is "ON"
any other 12v stuff work ? waterpump Interior lights?

If flat battery ... turn on the converter (while on shorepower or generator)

if good battery volts and OTHER 12v stuff works
follow the wiring on the USB to battery see if there is a inline fuse ...
or.............. a fuse in the main fuse panel...
DONT rely on the LED lights to determine if there is a blown fuse
check the fuse with a multi meter

 

[hamrover]

Those were connected with crimped wire nuts to the usb port leads. I measured 1.6v at the bare wire in the nuts then cut the connection to check that there wasn't a load in the port that was the cause of the low voltage. So those wires are the power to the port.

It's kind of goofy but my factory installed USB ports only work if I have shore power or the inverter running, which makes me think they have their own converter somewhere, which steps down to 12V and then maybe the receptacle takes it down to 5V.

Just on a hunch try with shore power on and or the inverter running.

Since everything in my world is USB powered, I have never used the factory installed ones, and instead I ran my own 12-volt line to a a USB hub with 10 ports that I can use without running my inverter.

 

[hamrover]

My next step after that would be tracing that white wire as far as possible. Potentially one leg has come loose from a wire crimp somewhere. I have encountered this before.

 

[Michael.Brock]

Thanks for all of the suggestions!

But how exactly does one trace the wiring? Or add new wiring? Accessibility is not very good in these trailers (I guess not much different than in a house).

 

[Aussieguy]

It's kind of goofy but my factory installed USB ports only work if I have shore power or the inverter running,

when on shorepower ..... turn off the converter breaker
converter may be proving 12v

make sure your battery is charged and turned ON , check the battery disconnect switch and small 12 breaker near battery

try also... battery ON shorepower OFF
make sure lights and waterpump are working.
do the USB's work on battery
---------------------------------------------------


if your USB is ON a 120v outlet faceplate... good sign it is 120v
take a faceplate OFF and look to see how it is wired...

 

[TexasRangleRvLady]

Our trailer is a 2023 Norther Spirit 2145rbx we bought used late last year. There is a two-port USB outlet on each side of the bed. These worked when we first got the trailer and there is a blue light on the panel which indicates it is receiving power. Some time during our last trip both outlets stopped working and the blue light now does not light. I pulled a panel in the basement and checked the voltage and the 12v USB outlet is only receiving 1.6v I disconnected the usb outlet itself to verify that there is no load in the outlet. I pulled and checked all of the fuses in the converter panel and checked all of the breakers and all of them look good. Any suggestions for the next thing to troubleshoot?

Replace them. Mine get a lot of daily use in certain areas. I’ve had to replace 2 of them in 5 years. It’s not difficult and an easy and quick fix. About 15 mins.

 

[DJ252]

Not sure that it helps the OP but our USBs work on batt or shore power and I never measured how much they put out but when plugging a phone in to charge, a warning comes up that it is low powered.

They work, just not fast.

Tom, I can't swear that you'll never find a wirenut or crimped connection but so far, I only recall seeing Wagos and other, similar type connectors on non main, DC wiring.