Adding a portable solar panel to the ETI roof-mount unit

[Brookfielder]

Because we frequently camp in treed areas, and the 160 Watt roof-mounted solar panel on our 2017 19 isn't always in the sun, I snagged a portable 100 Watt Noma crystalline Solar Panel Kit when it came on sale at Canadian Tire.
I did a little labour exchange with a friend who is a welder/fabricator, who also happens to boondock in AZ in the winter (in previous years...), and has a nice design bracket for his panel array to rest on a flat surface or hang from a post or wall.
So far I've been able to connect the Noma panel directly to our batteries using its own controller and alligator clips, but the approximately 12' included wiring limits its location.
I would like to create quick connections for it at the front and rear of the trailer, and run it into the Go-Power GP-PWM-30 Controller, in parallel to the existing panel.

I've been told that in order to run more than one panel, they have to have the same voltage rating.

Looking through all of the information we received with the trailer, I have documentation for every component and accessory except the 160 Watt Panel. I only know that much because it is on our build sheet. Looking on the Escape website, I see reference to a 190 Watt optional panel, but no details.
Does anyone know the brand and model of solar panel ETI was using in 2016-2017? I'd like to see some specs on it.
For reference, the specs on the Noma are 18V Rated Voltage, 5.5A Rated Current. It also mentions "open circuit voltage 21.85V", and is discharge protected with built-in diode.

[Vermilye]

Originally Posted by Brookfielder

Because we frequently camp in treed areas, and the 160 Watt roof-mounted solar panel on our 2017 19 isn't always in the sun, I snagged a portable 100 Watt Noma crystalline Solar Panel Kit when it came on sale at Canadian Tire.
I did a little labour exchange with a friend who is a welder/fabricator, who also happens to boondock in AZ in the winter (in previous years...), and has a nice design bracket for his panel array to rest on a flat surface or hang from a post or wall.
So far I've been able to connect the Noma panel directly to our batteries using its own controller and alligator clips, but the approximately 12' included wiring limits its location.
I would like to create quick connections for it at the front and rear of the trailer, and run it into the Go-Power GP-PWM-30 Controller, in parallel to the existing panel.

I've been told that in order to run more than one panel, they have to have the same voltage rating.

Looking through all of the information we received with the trailer, I have documentation for every component and accessory except the 160 Watt Panel. I only know that much because it is on our build sheet. Looking on the Escape website, I see reference to a 190 Watt optional panel, but no details.
Does anyone know the brand and model of solar panel ETI was using in 2016-2017? I'd like to see some specs on it.
For reference, the specs on the Noma are 18V Rated Voltage, 5.5A Rated Current. It also mentions "open circuit voltage 21.85V", and is discharge protected with built-in diode.

The 160 watt GoPower ratings:

Rated Power (Pm): 160W
Maximum power voltage (Vmp): 18.6V
Maximum power current (Imp): 8.60A
Open circuit voltage (Voc): 22.5V
Short circuit current (Isc): 9.29A
Max power tolerance: ±5W
Cell type: Monocrystalline
Module efficiency: 16.4%
Series fuse rating: 20A
Max system voltage: 1000VDC
Weight: 26.4lb
Dimensions: 59.1" x 26.3" x 1.97"
Frame type/material: Clear anodized aluminum frame

They are close enough that adding a portable to the GoPower controller won't be a problem. Be sure to check polarity, and bypass the controller on the panel.

[Brookfielder]

Originally Posted by Vermilye

They are close enough that adding a portable to the GoPower controller won't be a problem. Be sure to check polarity, and bypass the controller on the panel.

Thank you for this! I had seen mention of GoPower being the vendor of choice for ETI, but I didn't want to assume.

Polarity check makes perfect sense to me.
When you say "bypass the controller on the panel", are you advising that I not use the Noma controller and wire both into the GoPower controller? That is what I had in mind so I could see the total contribution of both panels in one place, so I wold like confirmation before I let the smoke out of something...

[7th Heaven]

Originally Posted by Brookfielder

Thank you for this! I had seen mention of GoPower being the vendor of choice for ETI, but I didn't want to assume.

Polarity check makes perfect sense to me.
When you say "bypass the controller on the panel", are you advising that I not use the Noma controller and wire both into the GoPower controller? That is what I had in mind so I could see the total contribution of both panels in one place, so I wold like confirmation before I let the smoke out of something...

Exactly ... only allow one controller to be in control.

I recommend that you add a few quick connects so you can bypass the portable controller when connected to your Escape. If/when you need it for other purposes ( like recharging your dead tow battery if needed) the portable controller is still available.

Here is the cable kit I also carry along ... note the bits that allow us to use our 30A 110 extension cord with the panel. ( Idea stolen from some other smart soul here on the forum)

[Doug2000]

I'm am only an occasional solar user. I prefer to plug in to a post.

My understanding from reading in the past, correct me if I'm wrong, I thought all the panels connected to a controller had to be the same voltage and the same wattage. I thought all the panels had to be the same. I understood it that if you had a roof top and a portable you needed individual controllers each wired to your battery bank.

I don't recall the source, could have been YouTube or the Arizona Solar Forum.

[Perry Butler]

You already have a controller for your portable? If so, just run the wires directly to your battery. Why get into the matching game so you can use just one controller.

We have the 170 GoPower panel/controller setup from ETI. When I added a 100 watt Renogy portable I included three 15' cables to reach the Zamp port, that is connected to a Victron 100/20 controller, 10a circuit breaker, that connects to the battery. The ETI system is on it's own separate circuit to the battery.

100 watt panel> cable(s)> Zamp port> Controller > Circuit breaker >Battery

Save yourself the hassle of connecting to just the GoPower controller and wire your existing controller directly to the battery. This also gives you redundancy.

Enjoy,

Perry

[tdf-texas]

Originally Posted by Doug2000

I'm am only an occasional solar user. I prefer to plug in to a post.

My understanding from reading in the past, correct me if I'm wrong, I thought all the panels connected to a controller had to be the same voltage and the same wattage. I thought all the panels had to be the same. I understood it that if you had a roof top and a portable you needed individual controllers each wired to your battery bank.

I don't recall the source, could have been YouTube or the Arizona Solar Forum.

Rule of thumb for connecting solar panels:

If the panels are the same voltage but different amps, connect in parallel using either a PWM or MPPT controller.

If the panels are the same amps but different voltage, connect in series using only a MPPT solar controller.

If the panels are the same voltage and amps, connect either in parallel using either a PWM or MPPT controller or connect in series using only a MPPT controller.

-- ignore wattage as it's irrelevant.

[Vermilye]

You have a choice. If you use the controller on the portable panel, you should not connect the portable controller output to the input of another controller (the trailer's). The portable controller would drop the portable panel voltage down to the low teens, well below what is coming from the rooftop panels. Even if the portable panel worked not connected directly to a battery, the portable controller would load down the rooftop panels to the point where they would produce little output.

If you wish to use the controller on the portable panel, connect it directly to the batteries, either using the included clamps, or by adding a port.

If you wish to make use of the extra capacity of the built in GoPower controller, you must bypass the controller on the portable panel & wire directly from the panel output to the input of the trailer's controller. As long as the panels are reasonably close in voltage, wiring them in parallel will work.

I prefer to use the trailer's controller for both sets of panels. It is usually more sophisticated, and I don't need to go outside to see what is happening. Still, there is no problem using two controllers as long as they are both connected to the batteries. When I did this, every once in awhile there was a bit of interaction between the controllers, but it was rare and minor.

As 7th Heaven pointed out, adding a set of connectors between the portable panel and its controller makes sense since it allows you to use the portable either with or without the controller. It also lets you disconnect the input to the portable panel's controller when not connecting it to a battery; a good idea since most controller manufacturers suggest/require that the battery be connected before the panel.