Solar panel charging issues

[Machinetools1]

Hello there Thor owners

I have a 2019 Thor 29M Windsport. I put 4 100 watt solar panels on the roof with a 40 amp Renogy Rover 40 amp MPPT controller. I wired the 4 100 watt panels in Series/Parallel. I measured 35.5 volts under overcast conditions with all panels hooked up in Series/parallel.

When I hook up my positive and negative wires to my roof solar inlet my Renogy Rover 40 amp controller shoes It is not getting any charge from the solar panels.

I looked under the beds bird nest of horrifying wires and see no loose wires hanging.

I went on the Thor owners web-sight and cannot locate the wiring schematics for the solar system. My question is...what am I missing and why is it not working.

[m1noel]

I had to call Thor. They emailed me drawings of the solar wiring for our Aria. They were a great help.

[Chateau_Nomad]

Where did you measure the 35.5 volts? At the panel cables on the roof? Have you tested the voltage with a multimeter at the charge controller terminals... DISREGARDING what the charge controller says? Make sure there actually is/ or isn't voltage there.

If no voltage there (and you're feeling industrious) grab a LONG length of wire (or two) and test the continuity from the rooftop cable connector to where it emerges at the charge controller. That will give you a definite answer if it's connected or not.

I have NO idea where Thor threaded those cables... I'm just lucky mine work!

Good luck... hope that helps!

[16ACE27]

Originally Posted by Chateau_Nomad

Where did you measure the 35.5 volts? At the panel cables on the roof? Have you tested the voltage with a multimeter at the charge controller terminals... DISREGARDING what the charge controller says? Make sure there actually is/ or isn't voltage there.

If no voltage there (and you're feeling industrious) grab a LONG length of wire (or two) and test the continuity from the rooftop cable connector to where it emerges at the charge controller. That will give you a definite answer if it's connected or not.

I have NO idea where Thor threaded those cables... I'm just lucky mine work!

Good luck... hope that helps!

Why do you need a long length of wire?
Disconnect the solar panels
The the two embedded wires together.
go to the other end an do a continuity test.

Of course the voltage measurement at the controller input would have told you the same thing.

Break in the wires?

Run two new wires.

[Machinetools1]

The 35.5 volts are from all 4 of the solar panels connected. Each panels is 17.5 volts. I guess when you connect in series/ parallel it will measure only 2 panels in volts.

I am not sure if the solar connection port on top of the motorhome goes just straight to the 40 amp MPPT Renogy controller or it took a detour somewhere. Like to the inverter, fuse panel a breaker or ? Is there a fuse or something I am missing?

I did not check the 40 amp MPPT controller solar wires for power. I looked at the controller to see if the solar charging symbol was showing solar power going to the battery. I will hook the solar panels back up and check if voltage is coming into the controller.

I am just not sure if the wires from the solar roof port to the controller takes a detour somewhere.

I guess, as you can tell I am not Johnny electrical and I lack some skills in this department.

[Judge]

So your post is slightly confusing..... let me back up with what you should be doing and some info.

If your coach was equipped as "Solar Prep" from Thor there is an Orange/Black and White 10AWG wires that run from the MC4 Cable Entry on the roof down to the electronics bay and they terminate there. They are typically tied together with black electrical tape. Back when Thor came out with "Solar Prep" for their coaches they were only prewired witht the roof MC4 cable entry but there was no controller.

The early "Solar Prep" coaches had no fuses installed. There are no terminal blocks. It was one wire run from the roof to the electronics bay. You were responsible for adding your own fuses.

Now if your coach came with a 10A PWM Controller from Thor and you replaced it with the Renogy 40A MPPT, Thor would have installed an inline 10A fuse. If you didn't replace it with a 40A fuse, you could have blown the fuse with your setup. That fuse is usually in the battery compartment.

Now when Thor does supply the controller, they do not add a fuse on the solar input side of the controller. I had to add my own when I swapped out my controller for a better one.

Before connecting the solar panel to your Controller, you should have the output side connected to your house batteries first. Some controllers recommend not connecting the panels to the controller before the batteries have been connected to the controller. The controller should be reading the hosue battery voltage.

Now if you have done all of that correctly, you need to start troubleshooting as Ted recommended. Take a cable with a male and female MC4 connector and connect it to the ports on the roof and then check your continuity where the wires terminate inside the coach to be sure they are connected properly at the roof terminals. There could always be a bad crimp on at cable entry on the roof.

[DavidEM]

As others have said check the voltage at the solar controller input. My guess is there will be none. So either there is a break in the cable inside the roof and walls or you have the wrong cable attached. Also it would be very unusual and kind of crazy if Thor wired that cable any place other than direct to the controller.

Also did you have a 10A controller in place before you started? Most solar prewires include a small controller. If not, how did you know which were the wires to the roof port?

And FWIW, series/parallel wiring of four 12V nominal panels should give you the 35.5 volts you are measuring at the wiring connection to the panels that you measured. So that part looks right if they are connected to a controller. If they are not connected, it should be more like 40 volts in full sun. Maybe in cloudy weather they would measure 35.5 if open circuit.

David

[Machinetools1]

Yes... The 2019 Thor Windsport came with a factory 10 amp PWM controller. I changed over to the 40 amp Renogy Rover MPPT controller. I followed the directions by hooking up the battery first then the solar panel wiring.

I followed the wiring schematic for series/ Parallel ( in picture).

I think I will take apart the roof solar port and make double sure the positive is the correct wire I am plugging the positive solar panels up to.

On my Renogy solar panels the hot lead is the male plastic connector. But has the female metal piece inside. So I assumed on my roof solar port it would be the same. The male plastic piece with the female metal piece is the hot lead. Here we go assuming... bad idea for sure.

I checked the voltage coming out of the roof solar port and I have no voltage with the solar panels not plugged in. I think I would not have any voltage as nothing is hooked up. I did not know if it would read what the controller says the battery voltage is through the roof port. I hope this makes since.

[Judge]

Originally Posted by Machinetools1

On my Renogy solar panels the hot lead is the male plastic connector. But has the female metal piece inside. So I assumed on my roof solar port it would be the same. The male plastic piece with the female metal piece is the hot lead. Here we go assuming... bad idea for sure.

.Attachment 34160Attachment 34161

I can't remember if it was my Outlaw or my current Magnitude but one of them was not wired with the (+) and the (-) at the roof cable entry port to match the MC4 (+) and (-) connectors on the solar panels.

[Chateau_Nomad]

Originally Posted by 16ACE27

Why do you need a long length of wire?
Disconnect the solar panels
The the two embedded wires together.
go to the other end an do a continuity test.

Of course the voltage measurement at the controller input would have told you the same thing.

Break in the wires?

Run two new wires.

A "loopback continuity check" may be okay for a quick and dirty - and it WILL give you some limited information - but not ALL the information you may need in this case.

A loopback may show a lack of continuity, but which wire? If there is a hidden fuse, is THAT the problem... or is there a loose negative wire at a hidden terminal point?

In which case you may as well start searching for a blown fuse. I just like to have complete info when I'm troubleshooting... a little more work up front, but can save frustration later. Just my preference...

[Machinetools1]

Does the roof port solar wires go directly to the Renogy charger. Or does the wires hook to something under the bed area then go to the renogy charger.

At work now and when I get off I will be able to get more answers.

[taylorbob1]

I’m with Judge & DavidEM on this one…
1) is there a blown in-line 10amp fuse between the roof and your new MPPT 40amp controller? You need to place an in-line fuse somewhere between roof and controller

2) is the THOR roof connector wired correctly? + to +, - to -

[DavidEM]

I suspect if the OP measures the voltage at the input to the solar controller he will find that the polarity is reversed. That would explain his symptoms.

And FWIW you do not need a fuse in the wire from the panels to the controller as long as the wire size is large enough for the expected current. The wire is 10 gauge which is good for up to 60 amps and with his series/parallel wiring it will only see as much as 15 amps. Also I doubt if Thor put fuse in that circuit. If they did, it would probably be in the solar port. But I have noticed that Thor does some things that are not necessary like bypass valves on the tankless water heater.

But again, measuring the voltage at the inputs to the controller will tell you a lot.

David

[Chateau_Nomad]

Originally Posted by DavidEM

I suspect if the OP measures the voltage at the input to the solar controller he will find that the polarity is reversed. That would explain his symptoms.

And FWIW you do not need a fuse in the wire from the panels to the controller as long as the wire size is large enough for the expected current. The wire is 10 gauge which is good for up to 60 amps and with his series/parallel wiring it will only see as much as 15 amps. Also I doubt if Thor put fuse in that circuit. If they did, it would probably be in the solar port. But I have noticed that Thor does some things that are not necessary like bypass valves on the tankless water heater.

But again, measuring the voltage at the inputs to the controller will tell you a lot.

David

Good advice!! And simple to check.

Come to think of it, when I "upgraded" mine from the stock 10 amp to a 40 amp controller, there was NO FUSE between the panel leads and controller terminals.

[Chateau_Nomad]

Regarding fusing a solar install... here is a great in-depth explanation from EXPLORIST.life:

https://www.explorist.life/how-to-fu...y-not-need-to/

[Machinetools1]

There was a 20 amp fuse in the battery compartment for the old solar PWM controller. I replaced that fuse with a 40 amp fuse when I went to the 40 amp MPPT Renogy Rover controller.

I hooked the wires to the new controller just like the old controller was. They could be reversed from the factory. With the solar panels not hooked up to the roof solar port, will I still get a voltage reading at the controller. If so what should it be?

The 10 gauge wires come directly from the solar roof port directly to the solar controller and does not go under the bed to any other electrical devices?

DavidEM: I was gonna place an inline 20 amp fuse going to the roof solar port, but you do not think its needed?

[Machinetools1]

By the way.... Thank you for everyone's help. I really do appreciate it. As stated the electrical portion I need a little guidance and just want to make sure I do not have a melt down in the driveway.

[Machinetools1]

Not to sound lame, but when you say loop back. Do I take the positive and negative off of the controller and tie them together. Go to the roof solar port and do A "loopback continuity check"? If so what should the reading be?


Chateau_Nomad..... Thanks for the fusing read.

[Chateau_Nomad]

Originally Posted by Machinetools1

Not to sound lame, but when you say loop back. Do I take the positive and negative off of the controller and tie them together. Go to the roof solar port and do A "loopback continuity check"? If so what should the reading be?


Chateau_Nomad..... Thanks for the fusing read.

You're welcome!!

For the continuity check, First... MAKE CERTAIN your controller and panels are completely disconnected. You want NO POWER in the wires anywhere!

Go up on the roof and disconnect the panels cable from the roof port. Then use a jumper wire to connect the positive and negative terminals in the roof port together.

Then go down to where the wires enter the coach. Using the continuity "beep" setting on your multimeter, touch the meter leads to the negative and positive wires. You SHOULD get a "beep" because you completed the circuit - a loop. If you get a "beep"... the wires are solid.

You COULD achieve the same without a jumper... just connect the two wires inside the coach coming from the roof... then take your multimeter up on the roof. Stick one of your multimeter probes/leads in the positive roof port, and the other into the negative roof port. Same result...

To check for REVERSED polarity of the wiring - obviously FIRST remove any jumper wire on the roof port! Then make certain the wires inside the coach are NOT touching each other, or anything else. I suggest temporarily putting wire nuts on them. (This is why I suggested using the jumper wire method above )

Plug the panels back into the roof port. Go back into the coach where the wiring connects to the controller. Set your multimeter to DC-automatic. Then CAREFULLY touch the multimeter leads to the wires - NOTING which wire you touched with the positive multimeter lead and vice-versa.

If the voltage reading is negative (has a "-" in front of it), the RED multimeter lead is touching the NEGATIVE (ground) coming from the panels.

Now, if you reverse your leads (touch opposite wires) you should get a positive (+) voltage reading... which is what you want.

I suggest, REGARDLESS of the color of the wires, that you tape/mark the wires in some way to avoid future confusion.

[DavidEM]

Originally Posted by Machinetools1

There was a 20 amp fuse in the battery compartment for the old solar PWM controller. I replaced that fuse with a 40 amp fuse when I went to the 40 amp MPPT Renogy Rover controller.

I hooked the wires to the new controller just like the old controller was. They could be reversed from the factory. With the solar panels not hooked up to the roof solar port, will I still get a voltage reading at the controller. If so what should it be?

The 10 gauge wires come directly from the solar roof port directly to the solar controller and does not go under the bed to any other electrical devices?

DavidEM: I was gonna place an inline 20 amp fuse going to the roof solar port, but you do not think its needed?

You absolutely, positively need a fuse between the solar controller and the batteries. With as much as 30A of solar output (when you get the wiring sorted out ) the wire in that circuit needs to be bigger than #10 to minimize voltage drop. I would use #6 gauge and a 40A fuse would work best.

You don't need a 20A fuse on the other side of the controller as the panels will never produce enough current to blow it. But it won't hurt to have one.

David