☀️🔌⚡️ The Ultimate RV Solar System! 8 Panels, 1,300 Watts, Off-Grid Ready!

TheRVgeeks Electrical, Solar, Updates & Upgrades 18 Comments

Our three original RV solar panels output a maximum of 375 watts. Switching from a standard RV refrigerator to a residential fridge meant that that wasn’t nearly enough to keep up.

When we upgraded our house batteries from AGMs to our new Xantrex eGEN Lithium battery, we saw a big improvement in our ability to boondock (dry camp without hookups) without running our generator. But having all of that capacity in our battery bank only made it even more evident that our solar system was inadequate. Sure… the lithium battery accepts a charge faster than the old AGMs, and provides many other benefits, so our meager system did better than before. But it wasn’t enough.

That’s why we upgraded our solar to a total of 8 panels putting out 1,300 watts! The new system is made up of two different types of panels, both from Xantrex:

  • 4 x 160 Watt “traditional” rigid glass panels
  • 4 x 165 Watt Xantrex Flex Max semi-rigid “peel-and-stick” panels

There were several reasons we chose Xantrex panels. For one thing, we love all of our current Xantrex equipment, so we decided it would be best to stick with a brand that had proven itself to us already, rather than piece together components from other manufacturers. Plus, the new panels offer advancements that aren’t commonly found in commercially-available panels today, bringing together several technologies that improve efficiency & durability. Those enhancements include:

  • 5-busbars: Standard solar panels typically have between 2 and 4 busbars (the thicker metal conductors that you can see joining the cells together in a solar panel). Having more busbars increases the panel’s efficiency (electrons generated in the panel don’t have to travel as far to be “collected”) and its durability (any damage/breaks in the conductors means electrons can find another path more directly).
  • PERC technology: This stands for Passive Emitter & Rear Conductor (or Passive Emitter & Rear Contact). Don’t ask us to explain exactly what that means… but we CAN tell you why it’s good!  😉 It’s another technology that boosts the efficiency of the cells in the panel. That means Xantrex panels can generate the same amount of power in less space… and the rigid panels reach 18% efficiency (the highest available for mass-market, commercially-available solar panels).
  • ETFE top layer: This is a feature of Xantrex’s flexible panels (standard AND Flex Max versions). It’s a more-durable coating than is typically used on semi-rigid panels (which should extend the flex panels’ useable life… “cheaper” panels are prone to scratching/etching/staining that reduces their output). This layer also offers better light-transmittance than standard coatings, meaning the Xantrex panels can generate more power from the light they’re exposed to… especially in low-light conditions (think early/late in the day and on cloudy days).
  • Mesh Grid conductors: This is a feature of the Flex Max panels. If you look at them closely, you’ll see a fine mesh of conductors radiating out from the larger busbars. Again, this mesh provides two benefits: greater efficiency (shorter electron path) and improved durability (breaks/cracks in the conductors don’t prevent parts of the cell from generating power as much as standard wiring configurations would).
  • Build quality: The Flex Max panels are an incredibly solid and sturdy design… far more robust than any flexible panels we’ve ever seen.

During the planning phase of the project, we talked quite a bit with our friend Brian of RVwithTito. He’s done quite a number of solar projects over the years, and it was great to be able to bounce ideas off of him and validate our plan. Plus we also got a lot of input from our friend and co-host on The RVers, Tom of Mortons on the Move. As an electrical engineer with lots of experience planning & installing his own solar array, his input was invaluable. When it was time to actually do the work, Brian even came over to help (and provide moral support)! Thanks to you both, Brian & Tom!

We have the 8 panels wired into two groups of four (4 x rigid and 4 x flexible), with the panels of each group wired in series (positive-to-negative, which adds up the voltage from each panel, while the amperage output of the array is equal to a single panel). Each series of panels is then wired (via 6-gauge, heavy-duty cables run from the roof) through a circuit breaker to their own MPPT charge controller. This arrangement allows each controller to maximize the output from each series of panels. It wouldn’t be as important if all of the panels were laying flat on the roof. But because our rigid panels are mounted on SolaRVector lift kits, they can be tilted to point more directly at the sun during the winter months, when the sun stays lower on the horizon. As a result, the two sets of panels (one tilted, one flat on the roof) can perform at their best. Had we wired the two sets of panels to a single charge controller that controller (A) would have had to be large enough to handle the output of all 8 panels and (B) would have had a hard time finding an optimal operating voltage for panels that are seeing such dramatically different levels of sun.

We’re thrilled at how well the entire system works. Even in December, during the shortest days of the year when the sun stays low along the horizon, our battery reaches 100% before the end of the day. And that’s with our residential refrigerator running, and both of us busy on our laptops (these videos don’t edit themselves, LOL!). Of course, if there are a few cloudy/rainy days in a row, we still end up running the generator. But, luckily, we don’t see many of those in the desert southwest! 😉

Read more about Xantrex’s solar gear here: http://www.xantrex.com/power-products/solar/overview.aspx

Check out more details about our cool, remote-controlled lift kits from SolaRVector here: https://www.solarvector.net

And, of course, head on over to Brian and Tom’s websites to see what great stuff they have going on:

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We're handy RVers, not professional technicians. We're happy with the techniques and products we use, but be sure to confirm that all methods and materials you use are compatible with your equipment and abilities. Regardless of what we recommend, consult a professional if you're unsure about working on your RV. Any task you perform or product you purchase based on any information we provide is strictly at your own risk.

We sometimes receive products for evaluation at no cost, and The RVgeeks are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. But our opinions are our own, you won’t pay an extra penny, and we only link to products we personally use, love and can recommend to friends with complete confidence.

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Comments 18

  1. Thanks for all the detail and the recommendation of installing the MPPT controller. It looks like you used the Schneider Electric Conext MPPT 60 PV Solar Charge Controller and not the Xantrex MPPT 30 Controller. Is this correct? Where did you place the charge controllers on your coach?

    1. Post

      Hi Mike! We went with the Schneider Electric MPPT controller for 2 reasons:

      1. At the time we did our install, Xantrex didn’t offer the current MPPT 30 controller. They only had a 30-amp PWM unit. Since we wanted to wire each group of 4 panels in series… we couldn’t use that controller.
      2. The currently-available 30-amp MPPT controller isn’t large enough to handle 4 x 165W panels in series. It can handle up to 3 panels no problem… but the fourth puts the output over it’s 30-amp capacity. Particularly on the rigid panels when they’re tilted (we’ve seen upwards of 50-amps of output from the Conext MPPT controller on the rigid panels). It wouldn’t be that much loss on the Flex panels (likely just a couple of amps during the peak of the day), but with a system this size, why have ANY unnecessary loss?

      Our charge controllers are in two different locations. One is mounted in our electrical compartment… because that’s where the factory-installed (though upgraded to 6-gauge) solar wiring terminated. We brought the second run of 6-gauge wiring for the other series of panels down into the basement near our inverter/charger… and mounted the second charge controller to the chassis rails there.

      Hope this helps!

      P.S… if you’re planning to wire your panels in parallel (more shade tolerant), the difference between MPPT and PWM controllers is less important.

  2. You’ve now had the SolaRVector system for several months. How many miles have you logged since the install and have you experienced any issues since the install?

    1. Post

      Hi Steve. Good question… we did our usual snowbird travel this year with them installed, so we covered about 5,000 miles (give or take). No issues whatsoever with the SolaRVectors… other than the fact that they can’t prevent clouds! 😉 LOL!

  3. An excellent video; what a solar system you guys have installed!

    We just finished attending your solar/lithium seminar with Tom and Cait Morton at the RVillage 2020 rally. It was both informative and thoroughly entertaining. (Sorry we didn’t come up to say “Hey” afterwards, but you guys were swamped by people with follow-up questions.)

    Both your video and your seminar made us reflect on the need for a solar/lithium upgrade to our original 2001 Newmar NewAire motorhome. We do not boondock, so it would seem the best upgrade for us to make is to switch from flooded lead acid batteries to no-maintenance AGM batteries.

    We currently have six high-maintenance 6V GC2-ECL-UTL 225Ah Interstate batteries. (Ugh.) Is there an AGM brand you are experienced with that you would recommend we look at?

    Thanks again for all the DIY help over the years.

    1. Post

      Hi Tom & Peg! Thanks for coming out, and for the nice comments. Sorry we didn’t get to say hello afterward. We’re still hoping to get a chance to see your New Aire while we’re here. We think your choice of AGM is a very good one based on what you’ve said. We used Lifelines originally, but now have switched to the Full Throttle series by Fullriver for our starting batteries. Both are excellent. If you go with Fullriver, we suggest the deep cycle, not the dual purpose.

      1. Peter and John: We’re so glad you made the time to stop by and tour our 2001 NewAire. When you get a chance, send us an email address and we’ll forward a group photo.

  4. This is an excellent video. As I was watching athy was in the other part of the room and commented that John’s voice is very eary to listen to as he explains the system and reasons for your choices.

    1. Darn, forgot the hold-the-shift thing.

      . . . . The first thing I noticed was the excellent paint job you had done last summer. Very timely.

      Also, now I can be envious of you guys: TILTING solar panels is the way to go. I actually drew up some ideas to tilt mine with actuators but that has not got past the thinking/drawing ideas stage.

      I was also most impressed that you did this at home with help. You live in a beautiful part of Beautiful British Columbia.

      Take care, John

      1. Post
  5. Thanks for responding. We are getting ready to install solar on our Thor Chateau as the 2 AGM 100ah batteries and inverter are not enough to keep our residential fridge going. We did not know Xantrex made solar panels. We have not yet finalized which panels or how many as we are in the early stages of doing the install.

  6. Great job guys! A fine example of why RV electrical systems need to be engineered and designed properly. One seemingly minor change can really upset the overall design and require going back to the drawing board. Or if not designed correctly in the first place, a system that performs poorly and inefficiently, costing more money in the long run. I’ve read a lot of postings by people trying to do this stuff on their own and really failing at it on many levels.

    Thanks for all that you do to help keep the rest of us (RVers) well informed and hopefully out of trouble. One of these days our paths will cross and it will be a total pleasure meeting you (both).

    1. Post

      Thanks, Joe! And we agree on that… you have to be careful with how your system is designed and installed, to ensure it works as expected. And, unfortunately, that can apply to “professionally installed” systems, too. We’ve heard from several people who thought they were having competent, qualified installers design their systems, only to have significant trouble (and more costs to FIX the things that were done wrong). Often because of difficulties integrating the installer’s standard equipment with what was factory-installed on the RV. Can be frustrating!!

    1. Post
  7. My understanding is when you wire them in a series, if any panel in the series gets hit with shade it shuts down ALL panels wired in that series. Why did you choose that wiring over parallel wiring? Also, are you concerned that the flat panels sitting on the roof will not have enough airflow when it gets hot? This reduces their longevity. That is a negative for flat panels.

    1. Post

      Hi Ellen. When wired in series, shading on a single panel DOES affect the whole series… but “shuts it down” is a bit strong. Newer panels have better wiring/circuitry to help reduce (though not eliminate) the effect. As we mentioned in the video, part of the reason we went with “Series” wiring rather than “Parallel” was two-fold: (1) to reduce the size of wiring needed between the panels & the solar controller (higher voltage/low amperage current doesn’t require thicker wiring to prevent loss… wiring in parallel gets you the opposite situation of lower voltage/higher amperage) and (2) to allow the MPPT solar charge controllers to adapt their operation to maximize the output from each string of panels (tilted rigids -vs- flat flex panels).

      As far as the longevity of the flex panels mounted flat on the roof, time will (of course) tell on that. But there are a couple of things (so far, purely observational… not data-proven) that have us feeling fairly hopefuly it won’t be much of a problem. First, the flex panels have actually been cooler-to-the-touch than the rigid panels are when in full mid-day sun. And that’s with the rigid panels mounted above the roof, with plenty of airflow beneath them (not tilted). It’s still early enough in the year that the sun isn’t directly above us, which could be a factor. So we’ll be keeping an eye on that. But it HAS been noticeable. The second is that two of the technologies in these Xantrex panels (the ETFE coating and the PERC structure) have the THEORETICAL advantage of reducing temperature gain in the cells. That’s partly to do with the frequencies of light involved and the way the light is “handled” within the cells (this is all above our pay grade, LOL!). So, again, we’ll see.

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