Sunday, January 11, 2015

200 Watt Solar Panel Installation on Roadtrek Agile

I’ve been eyeing on AMSolar Sunrunner Signature System kit for a while and when they had a holiday sale last year, I grabbed that opportunity and ordered (2 )GS-100 solar panel kit, a SunRunner Signature 25 MPPT/6/ Pro Core kit, and a combiner box. Other needed items were purchased on Amazon, like the hydraulic crimper, a Sikaflex 221 sealant, etc. The AM solar kits were pretty much a complete set; you just need appropriate tools to complete the install. If you have questions, give Dave at AM solar a call, they are very nice people.

The SunRunner Signature 25 MPPT/6/Pro Core Kit comes with:
Blue Sky SB2512iX-HV MPPT Charge Controller
Wall Box for 2512iX-HV
Blue Sky Temperature Sensor
Blue Sky IPN Pro Remote
500Amp Shunt
30' Duplex-6/2 cable
Interior Wire Harness Accessory Kit
Blue Sea 30A DC Breaker
6 gauge x 5/16" cable lugs
Blue Sea Systems Mini On/Off Switch
6 gauge cable lugs-3/8" Ring
Glue Lined Marine Heat Shrink tubing 1/2" red
Glue Lined Marine Heat Shrink tubing 1/2"-black

Agile’s roof real state is fairly limited, but I figured out how to fit (2) 100-watt solar panels without losing any roof appliances. With careful measuring and using cardboard cutouts, it showed that one GS-100 panel would fit in between the fan and the AC and another one towards the rear of the AC. It is not the ideal solar panel placement as the AC shroud can cast shadow on the panels depending on the angle of the sun but there is no other placement option in an Agile. The space in front of the AC is also partially occupied with the Winegard antenna. To free up that space, I replaced the antenna with the new “Winegard Rayzar retrofit kit”. The kit came with a shorter mast, or you can use the existing mast but that would defeat the purpose for my application.  Without the antenna, one could actually fit (3) 100 watt panels on the roof but I’m not ready to lose my antenna just yet.

Update: I added a 3rd 100 watt solar panel (link here). The 3rd panel is made by Renogy (Eclipse Series) which has same small footprint and specs but a cost a lot cheaper than AM Solar sells (SP100 or the older GS-100), it also uses same SunPower back-contact PV cells (Amazon link: Renogy Eclipse 100 watt Solar Panel).

The smoke alarm located by the sliding door entry was replaced and relocated as the new charge controller/battery monitor will be installed in that area. I ordered the First Alert 2-in-1 CO2 alarm with built in battery that should last for about 10 years. With one less battery drain in the RV (CO2 monitor) that is a win for me.

Per PV panel rating, the 200 watt panel should produce about 60 AH, but in "real world" especially in RV application you should expect less than the rated spec. as there are so many variables in play in solar power production/ battery charging. Here is a good reading from AM Solar about solar system operating conditions: Click here.
Our energy needs is quite simple, just basic necessities like lights, occasional water pump use, phone charging, or maybe catching the local news on TV if we are within the reception area, etc. We almost stay out of the van during the day, hiking, mountain biking or just relaxing and enjoying the outdoors during camping. I’ve replaced all RV lights to LED, TV/DVD to 12 volt to save power by not using the inverter. I still use the inverter once in a while if I’m in the mood for some loud bass music (not when camping), or just needed a quick 110 volt power.

WARNING! Before starting, read and follow all safety information and instruction in your installation manual to avoid personal injury.
The plan.

Cable routing is the hardest part of the installation. I mounted the charge controller inside the cabinet next to the coffee maker. The cables to the battery/ shunt were routed into the driver side A-pillar then through the opening on the engine firewall behind the steering column. Routing the cables through the A-pillar was tricky as there is not much room on the upper most part of the A-pillar. I use a borescope to guide the fishing cable into and out of the A-pillar. One could possibly route the cables down the driver side B-pillar then into the foot well, but I did not try that approach.  

Cable routing from charge controller to batteries.

Cable routing from the charge controller to the combiner box mounted on top of the roof was a little bit easier. The cable was routed into the space above the cab headliner then out into the area behind the switch panel then feed through an opening of a roof bow structure (pictured above) then out to the roof cutout.

I made the hole exactly in the middle of the roof rib structure so the PV cable can be easily routed inside. First, a small pilot hole was drilled through the marked location on the roof; a handheld borescope is then used to double check the hole final location. Once set, I used a bimetal hole saw to make the bigger hole for the cable. If you are planning of adding a third panel in front of the exhaust fan, you may want to move the combiner box a little bit forward so it will be under the third panel.

My initial plan was to mount the combiner box under one of the panel, but cable routing is one of the biggest challenge.

 Pilot hole location is exactly where I want it to be.

 3/4" diameter hole done. Rustproofing is applied along its edge.

 Found this PVC piece at local hardware store. I used it to protect the PV cable from the roof hole sharp edges. Half of the upper ring portion of the PVC was hacked off so it would fit in the combiner box rectangular opening.

 This is how it is going to fit in the combiner box opening.

 Combiner box mounted and sealed.

 Cut-out made for the charge controller monitor. This is where the factory smoke alarm was installed.  The smoke/ CO2 alarm was relocated next to the AC thermostat.

 Carlon 2 Gang Outlet box for old work with 90 degree clamp type wire connector. The IPN remote cable is routed to the charge controller inside the cab headliner via a small hole on the headliner used by the surround speaker wire.

 Outlet box installed.

 Fabricated a battery post-to-shunt connector made from copper flat bar.

Blue Sea 500 amp DC Shunt with battery post connector installed.

 I also made an acrylic cover for the battery shunt as pictured above.

 The factory acrylic cabinet door covers were replaced with aluminum decorative screen for air flow. The charge controller faceplate which also acts as heatsink does get warm during operation, so a good air movement around the controller is needed esp. during hot summer months.

All wired up!

 Battery insulation/ heat barrier was installed to prevent the battery from getting too warm from engine generated heat. With the new IPN ProRemote and battery temperature sensor, I just now realized how the batteries gets really warm under the hood.

 Close-up shot of battery shunt with acrylic cover.

Underside of solar panel with gauge #10 2-conductor cable spliced and sealed. I started working on the solar panel array as soon as the cable wiring's to the battery, the charge controller and monitor were done. Zip-ties adhesive back mounts  were used to secure the cable to the underside of the panel.

AM Solar solar panel mount. The rocker foot mount was attached into the roof using 3M VHB tape then sealed with Sikaflex 221. 

Before permanently affixing the foot mount into the roof, carefully inspect and pre-fit each mount into the PV panel bracket. The Sprinter roof has a slight crown that the vertical arm support of the foot mount will not be perfectly parallel with the upper PV panel bracket once installed. A slight bending of the arm support is needed to properly mate with the upper panel brackets (as depicted on the picture above), doing this prevents unnecessary tension to the VHB tape.

Solar panel cable with improvised connectors for the buss bar.  I use an uninsulated copper butt connector cut in half using a Dremel tool, each half of the butt connector is then crimped into the wire ends. Although not needed, you can just purchase a wire ferrules for this type of application. Some information that I've read mentioned that it is not really necessary and you can just connect the bare wire into the bus bar, but I've found out that once you start driving the bus bar screw in and it start pinching the wire, some copper strands does break. It may not be critical but I like it better the other way.

The hydraulic crimper does a nice job of cold welding the connectors. Once crimped, the connector and the copper wire strands becomes one solid piece of copper conductor.

Note: If you get a hydraulic crimper, make sure to use the correct dies for the size of the wire you are crimping. Even then, I still ended up slightly grinding off the opposing surfaces of some dies to get a proper crimp.

 Solar panels wired into the combiner box. Makes sure the solar panels are covered with cloth or something that will block sunlight until you're done connecting all the wires. The solar panels are wired in parallel due to panel shading issue.

 200-watt solar panels installed.

 Front solar panel.

 Rear solar panel.

 Rear panel cable run to the combiner box. To avoid possible scuffing of roof paint finish from cable movement/ vibration, cables were zip-tied away from the RV roof.

UPDATE: I recently added a 3rd 100-watt panel for a total of 300-watt PV system, see this post (click here).


  1. What kind of power are you getting from your 2 panels?

  2. It really depends on your location, season, and the angle of the sun to the panel (morning/noon/afternoon). Where I'm located the panel can generate between 7-9 amps (both panels) with good noon sun during winter, maybe closer to the panel spec. during summer which I haven't tried. You also get less power from the panel during morning or late afternoon.

    GS100 panel spec. listed below:
    Pmax = 100 watts @ maximum power
    Vmpp = 17.7 volts @ maximum power point
    Impp = 5.7 amps @ maximum power point
    Voc = 21.2 volts @ open circuit
    Isc = 6.10 amps @ short circuit

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  5. We just purchased a 2002 Roadtrek 190. Our son has been in solar for 25 years and plans to install a 315 W panel at the rear and a 100 W panel in front of the Fantastic Fan. This will require separate controllers. He checked the current required for air conditioning and for microwave and will go with a 1.5 kW PSWI. He is still researching Lithium Iron Phosphate batteries and plans to install between 3 and 5 kW-hrs. We have 9 kW-hrs of LFP in our 5th wheel and have been quite happy with Manzanita Micro 180 amp-hr (12 V nominal). We have four of these in the 5th wheel and two would be sufficient for the Roadtrek requirements (and space). Your writeup is quite good and I will suggest he takes a look at it for ideas.
    Reed and Elaine

  6. How much do you think I would have to pay for this system if I had someone else do the installation? I have a RT Agile also.

    1. I got the solar panel kit from AM Solar (, the 200 watt (2 panels) plus the solar controller kit sells for about $1237. They can also install it for you if you want, I’m not sure how much they would charge for the installation though…give them a call at 541.726.1091 or email them at and ask for a quote.

      If you want to save, you can get a cheaper solar panel kit/ solar charge controller online, it just happen that AM Solar had a Christmas sale that time so I took that opportunity. The Renogy 100 watt panel I added from this post ( is cheaper than what AM Solar sell. The Renogy Eclipse has same small footprint and specs than the AM Solar panel. Hope that helps.

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  8. Road Trekker,
    I am doing a first time solar install to the roof of my converted cargo trailer and am paranoid as hell about the wires under the panel getting buffeted around by the wind and am glad I found your site showing cable clamps mounted on the back of the solar panel. I didn't know you could attach anything there so could you please elaborate as to what kind of clamps, adhesive, etc. Thanks. This site find is a Godsend to me.

    Moving on,

    1. Hi Chuck,
      I used zip-ties surface mount (with adhesive backing) like this:
      Use couple of them to hold the cable under the panel to distribute the load. The junction box is similarly attached to underside of the panel, so I don't think it is a problem, mine has been ok for couple of years now. I'm glad you found this site helpful. Thank you.


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