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:
Featured & Related Products:
- Xantrex 160W Rigid Solar Panel
- Xantrex 165W Flex Max Solar Panel
- Conext MPPT 60-150 Charge Controller
- SolarVector Solar Lift Kits
- Duplex 6-gauge Cable (from panels to solar charge controller)
- Duplex 10-gauge Cable (power for SolaRVector kits)
- Liquid Tight Strain Relief for 6-gauge Cable (single opening… from AM Solar)
- Liquid Tight Strain Relief for 2 x 10-gauge Cable (two cable openings per unit… from AM Solar)
- Liquid Tight Strain Relief for 10-gauge Cable (single opening… from AM Solar)
- Waterproof IP67 Junction Box
- Dinkle Modular Solar Combiner (DK10N)
- Blue Sea 187 Series 30-amp Breakers (inline between panels & solar charge controllers)
- 40-amp in-line fuses (inline between solar charge controllers & battery)
- Cable crimping tool (for attaching lugs to 6-gauge cable)
- 6-gauge Cable Lugs
- Heat-shrink tubing
- MC-4 Connectors
- MC-4 Crimping tool
- MC-4 Wrenches
- 3M VHB Tape (0.75″ x 5 yards)
- Dicor self-leveling lap sealant
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