Adding a Solar Panel to 2020 Navion

[cthiggy]

Our 2020 Winnebago Navion 24V Sprinter came with two (2) Sunpower Solar Panels with a three (3) connector junction box on the roof. The Navion has a Xantrex 2000 Inverter and a Zamp X30S controller. We have swapped out the two (2) lead acid batteries for Lion UT1300 LiFePho batteries.

Question: Can we simply add one (1) more 100W flexible solar panel and plug it into the roof mounted junction box?? Are all solar panels equipped with one type of male connector??

Am I missing anything important??

Sincerely appreciate any and all suggestions/comments.

cthiggy

[creativepart]

Yes... and Yes and No.
Yes, you can just add another panel if you have room. And Yes, there is more to it. And, No, not all panels have the same connectors.

This requires that you dig in to the research a bit to make the change. Just like I hope you did when you changed to LFP batteries - more on that later.

Adding another panel is easy but you have to match the general output of the new panel to the old panel. If your current panels are 100w 12v nominal panels then then 3rd should be also. If they are 190w 12v nominal then it would be ideal if that's what you add as a 3rd panel.

But not all panels are 100w or 190w so, you need to learn what you have and then look for similar panels.

But, it's not that simple. When you add panels you are adding current to your system and the wiring in your RV, the rooftop Zamp portal and the Zamp controller have a 30amp limit. Which limits the amount of solar wattage on your RV to about 500w.

So, if you have 100w panels now, adding a 3rd is fine. But if you have 190w panels, adding a third is 570 watts... so, too much.

So, you must do that research first.

Next, connectors. Most PV panels come with MC4 connectors. But Zamp portals and inputs come with SAE connectors. You can look for and buy panels with SAE connectors OR you can buy MC4 to SAE adapters as needed. Also, you can easily change any one type of connector to any other on your own. More research on that is required.

The Zamp 3-Port rooftop combiner does require SAE plugs.

Every thing is the way it is... but every part can be changed out and made the way YOU want it to be.

NOW... about those LFP batteries? Did you just drop them in as replacements or did you also change out the Converter/Charger in your RV and also address your RV's Alternator charging while driving, as well?

If you have not then you are overdue for much more research on the LFP battery topic, too.

[cthiggy]

Creativepart,

Manny, manny thanks for the response. Can't tell you how much we truly appreciate your comments/suggestions.

Now I gotta sort out the electrical characteristics of the Sunpower solar panels I have.

NOW... about those LFP batteries? Did you just drop them in as replacements or did you also change out the Converter/Charger in your RV and also address your RV's Alternator charging while driving, as well?

Errrr, NO. Actually I was conversing by email with a gentleman on this forum who had installed the exact same batteries in a virtual identical configuration (same type Sprinter, same inverter, same controller, same, same, and he indicated he had not experienced any issues with the house generator nor the mercedes alternator. And so far, I have not identified any problems So, effectively, Yes, I simply dropped them in after making adjustments to the inverter and controller to allow for charging the LiFePho batteries.

Are you aware of any Mercedes Sprinter owners having problems??

Nevertheless, thanks again for taking the time to help.
cthiggy

[Redd22]

I have done the same thing as you on our 2020 View. Swapped out the AGM batteries for two 100 amp Renogy Lithiums. Made the changes to the solar controller and inverter. Sounds like you have that covered.

You can get better priced then Zamp panels and get the connector as mentioned above. But Zamp has been having some pretty good sales lately. The flat panels are discontinued but they still sell them for a great price of around $130 last time I checked. I picked one up and will keep it as a back up if one of the two originals fail.

I ended up picking up the Obsidian 100 watt hard panel on sale. Easy install and compatible plug. Also no holes to drill, just used the VHB tape included. Zamp also has great customer service if you need to reach out to them with questions.

Good luck.

[Marine359]

Determine if your controller will perform better with panels in series or parallel.
Typically, 100w panels have amperage rating of 5amps and Voc of 18-20v.
The only ironclad rule is that the array total Voc cannot exceed the Voltage rating of the controller. It’s ok if amps exceed controller rating because it simply won’t use the over-amperage.

Best bet is to try and find a third panel that comes close to the Voc of the ones you have. The voltage of the lowest rated panel’s Voc will determine array voltage (3x lowest Voc) if wired in parallel. As with batteries, Array voltage is additive in series. Amperage is additive in parallel. And array total amperage will be 3x the lowest rated panel. But voltage is more important than amperage when it arrives at the solar charge controller.

The advantage of Parallel is less power loss in partial shading. The advantage of series is that mppt controller are more efficient at higher input voltage.

I have 3 equivalent 100w panels, and I’ve wired them both ways. My particular panels (CIGS) perform better in series for total watts/day because they capture more wattage in early morning, evening, and partial shade than monocrystalline panels. However, I re-wired to parallel primarily so I could drop a harness down from the roof to connect my panels to a powerstation if need be. The array Voc exceeded the max voltage input of the powerstation, so I had to go parallel. Haven’t noticed a huge daily loss in parallel, maybe 5%.

[rx4fishing]

If you have the flat flexible Sunpower solar panels mounted directly on the roof, remove them immediately and inspect for damage. Winnebago does not use those panels anymore and is now using Zamp rigid panels mounted so not to damage the roof. Zamp’s polarity is also reversed from other solar systems. So make sure you check the polarity when plugging in another solar panel on the roof, if not using a Zamp solar panel.

[Fanrgs]

We have a 2020 24V with exactly the same setup as the OP. Our replacement batteries are even Lion Energy lithiums from Costco. I added an HQST 100w 9BB flexible panel from Amazon. Most solar panels have MC4 connectors, but the rooftop entry gland has SAE recepticles with the opposite polarity. So you need to use the adapter that should come with your MC4 to SAE cable to reverse the panel polarity. The panel has worked well despite its higher efficiency than the factory panels.

I also bought a 100w, nearly square, portable solar panel and cables from Harbor Freight for $89. It has legs that allow it to be set up at optimum solar angle. I use it in shaded dry camping sites and to supplement the flat rooftop panels when snowbirding in AZ. The rooftop amps are often reduced so much in low-angle winter sun that the single portable panel can produce about the same amperage as all 3. I connect the portable panel to the SAE solar recepticle in the utility bay.

The OP needs to make NO hardware changes to his inverter. The Xantrex Freedom XC 2000 is a converter-inverter that just needs to be reprogrammed for the lithium batteries. All the instructions are in the Xantrex manual. All the power sources into the MH go into the Xantrex--alternator, generator, solar, and 30A shore power. It can even be set up to prioritize one power source over another, eg., solar supplemented by alternator while driving.

BTW, I remounted my flexible factory panels and had no roof damage after 3 years! Winnebago likely switched because each 100w rigid panel is $40-50 cheaper than a 100w flexible panel.