Adding solar panel for Micro Minnie FLX

[Marine359]

Originally Posted by mfouts

There has to be a connection to the battery at some point. How do you attach a bus bar to the battery?
I have numerous Jeeps that I have attached a winch, running lights, and other accessories to the battery per instruction and they have been working fine for years.

Note positive battery cable attached to positive bus bar through ANL fuse. Negative battery cable attached to battery side of the negative shunt battery monitor. Load side of shunt connected to negative bus bar. Your battery location and battery fusing may be different on the FLX. Best to check with @electric.

[electric]

Of course it's possible to attach directly to the battery, but there are risks as I listed above. If you understand and mitigate those risks, then go ahead with it.
Although in the case of FLX the big DC breaker right after the battery positive is still pretty important last resort safety device, so if you want to wire closer to the battery then try to at least wire after this breaker.

[electric]

@Marine359,
your pic shows a very clean and easy to manage DC wiring setup. I use the same bus bars and DC disconnects in my own RV and other personal projects.
As a company we are pushing OEMs to use busbars instead of stacking studs as it's been done for decades. New WGO motorhomes have much better electrical designs, but there is still work to be done in towables.

[Steph]

I have attached the OEM wiring diagram I received from Winnebago. It shows the port is wired directly to the battery not to the controller.

[Steph]

I have attached the solar wiring diagram from Winnebago that shows the wiring to the battery.

[electric]

Originally Posted by Steph

I have attached the OEM wiring diagram I received from Winnebago. It shows the port is wired directly to the battery not to the controller.

Actually it does not show that at all. It's not even a wiring diagram, it's more of a mechanical drawing specifying wire routing. There is no way to discern which connections are made in the area where solar controller is drawn. No terminals, no port labels, no electrical details whatsoever.
It's ebmarassing for WGO to call these drawings wiring diagrams, just because there are wires depicted on them. Wiring diargams must show circuits, not wires, there is a difference.

[creativepart]

Originally Posted by Steph

I have attached the solar wiring diagram from Winnebago that shows the wiring to the battery.

It clearly shows the external port is wired to the GoPower charge controller.

[Steph]

Thank you for clarifying. I guess checking with voltmeter is the best way since I have read all FLX trailers have the external solar port connected to the controller and then others say it not. It is very strange that there is not a firm spec from Winnebago

[electric]

Originally Posted by creativepart

It clearly shows the external port is wired to the GoPower charge controller.

What does "wired to the GoPower charge controller" actually mean? Schematic shows 3 circuits coming towards the controller, but controller only has 2 ports on the back - solar and battery. So, where do you see on this so called "diagram" how 3 circuits are connected to 2 ports?

Imagine you are an electrical assembly tech at WGO factory making FLX trailers and you are given this "diagram". What happens next? My bet is that some units will come off the line with external solar port wired to battery port and some will have it wired to solar port.

So, as @Steph said above, measuring with voltmeter on your specific FLX unit is the only way to determine how to proceed.

[creativepart]

Originally Posted by electric

shows 3 circuits coming towards the controller, but controller only has 2 ports on the back - solar and battery. So, where do you see on this so called "diagram" how 3 circuits are connected to 2 ports?

Well, it's simple - they wire both the external port leads and the rooftop port leads to the one solar charge controller PV input. The other connections on the controller are the output to the battery bank. This yields 4 wires attached to the controller input and 2 wires attached to the controller's output.

That is what Winnebago did on my motorhome, and it is shown the same way on my wiring diagram.

I'm not disagreeing with you - it's confusing, inexact and not really detailed at all. All I was pointing out was that the diagram does not "show the port is wired directly to the battery not to the controller. "

I also agree that the best way to tell is to use a voltage meter to see if the voltage is about 18-21 volts which would mean it is connected to the solar controller or 13.6v-14.6v connected to the battery bank.

[electric]

Originally Posted by creativepart

All I was pointing out was that the diagram does not "show the port is wired directly to the battery not to the controller. "

I know I'm splitting hairs here and not disagreeing with you in general, but in electrical engineering when we say "wired directly to something" we don't neccessarily mean at the physical location of the thing, but rather referring to the same functional circuit where the thing is wired to. In other words "directly" means function, not location.

In this case if external solar port would be wired to the battery terminals on the solar controller, then I would say it's wired directly to the battery, which would result in measuring battery voltage at the external port.

[Steph]

I tested mine with a voltmeter and it is connected to the controller.

I spoke with Go Power, Winnebago, and Xantrex today they all conformed the solar port is wired directly to the controller.

Go Power said as far as they know, the FLEX models are the only TT's that do this. They also told me they have no portable solar suitcases that will work. All their solar suitcases were built and tested with an attached controller. Bypassing the controller voids any warranty.

Renogy has a 2000w suitcase with a built-in bypass. The AMPs and Voltage outputs for the roof top panels and the Renogy solar suitcase are almost identical, so it would be a good option.

Both Go Power and Renogy have 100w suitcase without controllers. However, you must buy a 200w panel to hook the exterior solar connecter. Connecting anything smaller will significantly degrade the entire solar system. Also, the 30AMP MPPT controller has a 600w maximum input, so you cannot add more than 200w.

[creativepart]

Glad you have some definitive answers.

We've had others here complaining about portable panels without controllers being an issue. What they've discovered is that if you look for portable systems made for "solar generators" that all of those "suitcases" come without a controller because the "solar generator" has a built in controller, too.

The other option and it's very sensible is to get a portable kit with controller built in and run it straight to your batteries rather than the external port.

I'm not big on Harbor Freight for things like this, but they do have such a "suitcase" portable:

https://www.harborfreight.com/100-wa...ase-57991.html

[Steph]

Have to be really careful here, that link takes you to 100w suitcase. Those cannot be used. Only 200w suitcases can be used

The issues I have with Jackery or other like companies is their suitcase are very expensive compared to Renogy. Renogy has a good reputation so why spend $200 to $300 more.

As far as connecting directly to the batteries, there are two issue there.

Issue one is that the FLX is a fully integrated system. Go Power and Xantrax recommended that this not be dome in my conversations. The reason is the solar, battery, and inverter charger are all connected together. If you connect directly to the battery, none of the readings on the panels in the FLX will be accurate.

The second issue is the 320AH battery is stored behind a panel with no easy access unless you remove the panel. So, to connect the battery directly you would either need to unscrew and remove the panel each time or figure out how to cut and install an access panel.

However, I think based on Issue one, connecting directly to the battery is not an option.

[Marine359]

If more than one panel is connected directly to the controller, then all the rules of parallel pv wiring apply. Voltage will be limited to the lowest voltage panel. Therefore the roof panel(s) and portable panel need to be electrically similar. Matching the voltage is more important than matching watt rating.

[creativepart]

Originally Posted by Marine359

Matching the voltage is more important than matching watt rating.

Exactly, as long as the rooftop panels and the portable panels are both 12v nominal (17v-22v) you can certainly use a 100w panel on the ground OR for that matter you could put an additional 100w panel on the roof, too.

[Steph]

I agree that Volts are the key.

I have done a lot of searching on portable solar panels and it seems that they all have a lower voltage that the mounted panels of the same wattage. I have also discovered in every case I looked, the voltage of the 100W suitcase is greater than the 200w suitcase. Renogy for example has an Vmp of18V for the 200W and a 20.4 for the 100W.

The current Go Power panels have a Vmp = 20.8V and an Imp of 19.24A combined. if you calculate the total watts, it is 20.8 x 19.24 = 400 watts.
You always use the lowest Voltage and the total Amps in the calculation.

Now let's say you use a 100W panel that has a Vmp of 20.4V and Imp of 4.94. Your total Watts is 20.4 x 24.18 = 493 Watts. For a Wattage loss of 2%.

Now if you use Vmp of 18V at Imp of 11.2 A you would have 30.44A x 18v = 574W. This is equal to a 10% wattage loss.

So, in this case a 100W panel would operate more efficiently. So, I stand corrected. Just get as close to a VMP of 20.8

[creativepart]

I have three 100w PV panels on my roof and not only are they not the exact same voltage, they output different voltages constantly. Sometimes I see 21v other times when a cloud comes over I might see 17v.

What you want are 12v nominal panels and they will output at MAX between 18-21v. In my experience it's not one number but a range.

A 12 volt panel, for example, doesn't put out 12 volts but it produces enough voltage to charge a 12 volt battery. It produces around 18 volts and has an open circuit voltage, without a load, of 21 volts.

What you don't want are 24v nominal or 48v nominal panels.

This may be a generalization, but small system RV solar panel matching is mostly about using all your panels of the same nominal voltage.

[Steph]

Panels will always produce different voltage based on sun exposure. However, the maximum Wattage that can be produced by all panels is always calculated using Vmp (lowest rated voltage of connected panels) x total IMP (total of AMPS for all panels).

As far as the open circuit voltage. This not important in determining total wattage of all the connected panels. Only Vmp is important.

You are certainly open to your views but from an engineering and scientific point of view if someone wants to understand the total wattage their panels will produce the above equation is the only way.

[Marine359]

Your statement that Vmp is the only important measure of panel voltage does not square with the manufacturers of solar charge controllers. However, you are correct in stating that Vmp will give you the most accurate estimate of total array voltage, and hence wattage production. Vmp is what determines maximum power point tracking (mppt).

Voc is extremely important when calculating total maximum voltage of an array. It becomes critically important when calculating how many panels you can connect to a particular charge controller. Exceeding the maximum controller input voltage at any time can and will damage the controller. It is possible for an array to exceed Vmp, but not possible to exceed Voc. Manufacturers of charge controllers use Voc for this calculation not Vmp. Vmp is good for getting a good estimate of array performance. Not all 100w panels are nominally 18-21v. My 100w CIGS panels are 30.5v nominal, and they test out very close to that on Voc.