Adding solar panel for Micro Minnie FLX

[Bobby-D]

Hello Everyone,
Does anyone have any knowledge about adding another solar panel to a Micro Minnie FLX through the Go Charge Solar on The Side plug?
The sticker on the side says you can use any solar panel, but I have read otherwise on different threads.
Can you use any solar panel?
Does the solar panel need a specific type of plug?
Does the plug in solar panel need a charge controller or does this plug connect to the charge controller already installed on the FLX?
Thanks in advance!
-Bobby

[Marine359]

Hi Bobby,
If “Solar on the side” is a sidewall port to connect a portable panel you should be able to use any portable panel that does not have an on board charge controller. Almost all panels have cables terminating in MC4 connectors. To connect the panel to your sidewall port, you will need a wire harness that connects to MC4 on one end, and matches your sidewall port connection on the other end. I’m guessing your sidewall port is an SAE/Zamp style socket. Select a harness when you buy it, that comes with a polarity reverser. It’s a little adapter that fits the sidewall receptacle on one end and connects to the harness on the other end. It’s used to reverse polarity, so before installing check using a multimeter the polarity of the receptacle to determine if you need to use a polarity reverser.

I believe your solar on the side sidewall port connects directly to your mppt solar charge controller on the inside. If that’s the case, you can buy pretty long extension cables pre-made with MC4 connectors. 30ft is a good length to chose because it’s long enough to place your portable panel in optimal sunlight, yet short enough that there’s virtually no voltage drop. But, be aware, that only works if you have a portable panel with no onboard controller. If you use more than one portable panel, wire them in series, as you do not want to increase amperage.

Post a picture of your sidewall port (close up) to confirm.

[Marine359]

Harness and plug should look something like this, maybe. Note harness between panel cables and sidewall socket.

[Amazonica]

I spoke with both Zamp and Bob at GoPower regarding my "Solar-on-the-Side" port not running my portable 140W Zamp Panels. The portable controller gave me "Over voltage" Error. Here's what I was told and verified with my multimeter (I'm not a Pro and this is not advice).

If the Voltage measured at the exterior solar port is 15V or above, then it is wired to the Solar Controller and not directly to the Battery. Bob at GoPower told me that Winnebago is one of the only manufacturers he knows that wires the "Solar-On-The-Side" to the solar Controller and not directly to the battery.

Mine measured 22.3V. My Zamp Solar Suitcase had it's own Solar Controller so we (I had help since I'm a sissy with electrical) completely bypassed that portable controller with some MC4 connectors and now it works like a charm. Zamp is known for their "non-typical" plug configuration, but I was able to plug it in to the exterior GoPower port with correct polarity and no problems.

[creativepart]

Originally Posted by Amazonica

Bob at GoPower told me that Winnebago is one of the only manufacturers he knows that wires the "Solar-On-The-Side" to the solar Controller and not directly to the battery..

Unfortunately, Winnebago doesn’t “always” do the same thing. This is why we usually suggest the voltage test you mentioned. Sometimes the port is wired to the solar controller and sometimes it’s wired to the batteries.

In fairness, the times Winnebago doesn’t wire the outside port to the solar controller is when they haven’t installed a solar controller because there are no solar panels installed on those models.

So if you have factory solar with a solar charge controller, the outside solar port is wired to the PV input side of the solar controller. But, if you have an outside solar port but no factory installed solar equipment, the port is wired directly to the battery bank.

I think!

[Old Navy]

It depends. If you currently have 2 190W or 200W panels wired in series, adding panels with much lower voltage could actually reduce your power. What do you currently have?

[creativepart]

Originally Posted by Old Navy

It depends. If you currently have 2 190W or 200W panels wired in series, adding panels with much lower voltage could actually reduce your power. What do you currently have?

It would seem, the portable panel on the external port would be wired in parallel with the series panels on the roof. I’ve always envisioned a series/parallel setup to be two series panels paralleled to another two series panels of roughly equal voltage. I have no idea what a mismatched series/parallel setup yields.

[Old Navy]

Originally Posted by creativepart

I’ve always envisioned a series/parallel setup to be two series panels paralleled to another two series panels of roughly equal voltage. I have no idea what a mismatched series/parallel setup yields.

That's the way to do it. I've seen a few posts here where people were told by their dealer that they could connect "any panel" to the solar on the side. But they really need to be at least similar VMP, or the system won't perform as well.

[electric]

Originally Posted by creativepart

I have no idea what a mismatched series/parallel setup yields.

Best case, if both parallel strings have blocking diodes, then string with less voltage won't make any power, but won't drag down the higher voltage string either.
Worst case, if no blocking diodes, less voltage string will drag down higher voltage string, drastically reduce useful power, turn mismatched power into heat, possibly burning up over time, like a fuse.

It is very strange to see external PV port wired directly in parallel with factory PV series string, without clearly labeling required voltage ratings and safety warnings.
External panels should have their own controller and go to batteries, it's the only sensible way of doing it.

[Old Navy]

Here's a link that provides a very basic description of what happens when you mix panels of different voltage and current ratings in parallel or series.

https://solarpanelsvenue.com/mixing-solar-panels/

[Marine359]

IMHO,
It’s well worth the small additional cost of installing a separate charge controller for a sidewall port. A Victron 75/15 costs only $150, and it’s small. Add a few bucks for wire and fuse, and an hour or less to install (assuming the port is already there). When you’re done, you’ll have pretty much complete flexibility to connect 200w or more on a 30ft 10awg cable with virtually no voltage drop.

[electric]

Originally Posted by creativepart

So if you have factory solar with a solar charge controller, the outside solar port is wired to the PV input side of the solar controller. But, if you have an outside solar port but no factory installed solar equipment, the port is wired directly to the battery bank.

I believe this is a false statement. It seeks to provide logical explanation to some evidence of PV voltage present at the port by some customers, and suggests voltage test to determine which wiring design your particular system has. But the fault in the logic is that direct PV voltage at external port has never been by design, so if/when it's observed, it's likely due to miswired units or solar breaker being in the open state.

By design the outside solar port has always been connected directly to the battery bank, thru the 30A breaker of course. It is always required that external panels have their own controller, to prevent voltage conflicts and backfeed of power in case of mismatched panels.

Voltage test is still valid and needed, but only to determine if your unit is miswired and needs fixing, or your solar breaker is open and needs a reset.
The marketing claim that any external panel(s) can be used is correct, with the assumption that such panel(s) come with their own controller, so the output voltage matches with battery voltage, regardless of OEM panels on the roof.

Another interesting observation is for distance and voltage drops. It is true that solar controller should be wired closer to the battery, to minimize voltage losses between controller and the battery, because this voltage is lower and any loss leads to undercharge. Voltage loss between panels and the controller's PV input is less important, because PV voltage is typically higher, hence PV current is lower, which means less losses in the wire.
So, if you make a custom setup for your external solar kit with a desire to place panels further away from your RV, then you should extend wires between panels and controller, keeping controller to battery connection short.

[creativepart]

Originally Posted by electric

By design the outside solar port has always been connected directly to the battery bank, thru the 30A breaker of course. It is always required that external panels have their own controller, to prevent voltage conflicts and backfeed of power in case of mismatched panels.

That would be great info if it was always true.

It may be always true for the FLX/Lithionics Travel Trailers and Motorhomes. But it is not true for my 2017 Adventurer and hundreds of other motorhomes that came with factory solar and SCC. The rooftop PV panels have no breaker - but a 30A fuse in the rooftop Zamp 3-input Portal. And the external outside solar connection is wired directly to the SCC on the PV input side.

In fact, there was a Federal recall because the external input was even lacking any kind of fuse.

These Winnebago factory OEM Solar installs were all done this way for a number of years.

So, while you may be totally correct about the FLX Lithionics products it is not correct about previous non-Lithionics OEM Solar setups. That's the thing about these things... Winnebago keeps changing things so it's difficult to find an absolute.

[electric]

Sorry, I'm relatively new to these Winnebago systems, so I'm being careful with my words and I can only speak to latest designs with Lithionics batteries, and with little definitive information I'm getting from WGO engineers in the towables division. I'm told that FLX solar port was supposed to be wired to the battery by design, but who knows what wiring mistakes are being done at the factory, very likely some units are miswired.

The best approach to external solar is to measure what you have, decide if what you have is wired to battery side or PV side, then decide how to best make it work for you.
Either adopt externally to what you have, or rewire internally.
I've already explained above, and see other members here ,like @Marine359 , say the same thing , the best option for external solar is to have separate controllers, either by adding one externally with panels (often sold as a kit), or hardwire one internally, according to the diagram I posted.

[mfouts]

So with this info. what would be the best way for an electrically challenged individual to add a solar panel using the solar on the side?

[BigE]

I am also challenged, but here is what I think.

Really depends on if the side port is wired to the controller or to the battery. Need answer to that first. I am trying to figure out the same thing, but won't know until I pick up my new WB2108TB on Friday.

If the port is wired to the battery, use a solar cell that has a controller on board or wire a simple controller to the battery and side port and use any panel you want without a controller. The latter is my preference. I hope I am wired to the battery.

If the side port is wired to the controller, worry about the compatibility of the roof panels and make your life more difficult. Then purchase a suitable panel without a controller.

[mfouts]

Today I checked voltage at the power on the side receptacle and it read 44 volts. I assume that means that it is ran through the controller that services the roof mount panels.
If I wanted to use as is, is there a downside provided i use a compatible panel?
How do I determine what compatible panel I need?

[Marine359]

If your side port is wired to the charge controller, you will want to connect a panel to the port that does not have an on-board charge controller, and which has a Voc that matches the Voc of your existing panels, that’s IF the existing panels are wired in parallel. If the existing panels are wired in series, then you’ll want to match up the amperage rating. It’s likely they are wired parallel. But to be sure you can go on the roof and check. While you’re up there, might as well measure the Voc of one of those panels.

[mfouts]

Sorry for some of these questions.
What is Voc and how do I determine that?
How do I tell if panels are wired in parallel or series?

[Marine359]

No problemo
Voc is Voltage open circuit. It is measured across the mc4 connectors on the panel. This voltage is what is used to determine the the total voltage of an array. It is additive when panels are in series. So two panels, each with a Voc of 20v would yield an array voltage of 40v. The array voltage must never exceed the input rating of the solar charge controller. If wired in parallel, amperage is additive (voltage is not). Array total amperage may exceed the output rating of the controller. The extra amperage will not be used.

Series is when the negative lead from one panel is connected to the positive lead on the second panel. The remaining mc4 leads are then connected to the mc4 gland on the roof.
Parallel is when both positive leads are connected together and both negatives connected together. This is normally done through a combiner harness first, which is then connected to the mc4 gland.

Hope this helps