Upgrading our Renogy RV Solar System to 400 Watts

Our First RV Solar Experience

About a year ago I popped my RV solar cherry and installed a simple little 200 watt RV solar kit from a company called Renogy. We didn’t have too much dough to spend on solar, but I believe I got a good bang for the buck with the roughly $400 dollar kit. Renogy panels seem to get very good reviews and after a year of use I’ll add to that with a full thumbs up. They are light weight but sturdy and put out decent amounts of power.

With the 200-watt starter kit, we were able to keep all our smaller electronic devices, camera batteries and 2 laptops all charged up plus top up our 2 six-volt golf cart coach batteries for the evening hours. We spent many weeks out boondocking where we never had to run the generator. As long as we stayed conservative with our energy use and the sun shone most of the day we could enjoy the peaceful atmosphere.



Why the Upgrade to 400 Watts?

We found that 200 watts of solar power was not quite enough to power a few of our larger electronic devices like for instance Anne’s 21” iMac computer or our 43” LCD TV. Both can draw anywhere from 50 to over 100 watts each. This is fine and dandy when the sun is strong and high in the sky, but as soon as it is gone we are dependent on our battery bank and whatever sun’s energy was stored in there. The large computer and TV can be easily run off my Champion Generator, but it sure would be less of a hassle and quieter to have the solar panels and 12-volt batteries power them instead.

Two other reasons for the upgrade are cloudy days and short winter days. Doubling our solar power might allow us to get by with just solar energy where last year the generator had to be fired up. Also, with these issues in mind I upgraded my battery bank from two big 6-volt golf cart style batteries to a bank of four.

464 AH RV Battery Bank

Boondocking almost exclusively from December to May on 200 watts of solar and 232 ampere hours of battery capacity was learning experience for me. It showed me that around 400 watts of solar and 464 AH of battery capacity should be the sweet spot for our particular energy needs. Rather than conserving power like mad, we can be a little more liberal with things and maybe run some “just for fun” stuff.

Installing Two More 100 Watt Renogy Panels

Since I had just completed the original Renogy kit install one year ago and it performed perfectly I only had to repeat the install process.  To expand to 400 watts, I simply purchased the same items found in the original 200-watt kit minus the charge controller.

Parts List:

2 – Renogy 100 Watts 12 Volts Monocrystalline Solar Panel

2 – Renogy Mounting Z bracket Kits

1 – Set of MC4 Branch Connectors

1 – 20-foot Renogy Extension Cable Kit

Opening the Renogy box

Mounting Location on my Fifth Wheel Roof

When I laid down the original 100-watt panels I did so with a future expansion to 4 panels in mind. I had envisioned mounting four 100 watt panels at the very front of the fifth wheel. Here my reasons for this decision:

  • Shadows on the panels would not be an issue
  • There was the perfect amount of space to mount the four panels sideways
  • They would be slightly tilted to capture more sun
  • The tilt would allow rain to run off
  • It’s the closest location to the batteries
  • It looks really cool!

4 Renogy 100 watt solar panels

Attaching the Solar Panels to the Roof

I decide to employ the same roof attachment method I used for the first two panels. I used the screws that were included with the Z-bracket mounts from Renogy. I first laid down some Eternabond Roof Tape under the aluminum Z-brackets. I use the tape as a bit of protection for the rubber roof membrane and to help seal the screw holes. It also provides a clean surface for the sealant to adhere to.

Then marked and drilled pilot holes for the screws using a 1/8th inch bit. Next I put a layer of Dicor lap sealant underneath the Z-Bracket and dipped each screw in more Dicor. I was careful when tightening down the screws to not overdo it and cause them to lose their bite. Finally, I applied a liberal amount of more Dicor sealant all over the bracket and screw tops.

Panel mount close up

This system of mounting the solar panels has worked well for me. Our original two panels have been there about a year now and are as securely fastened as the day I installed them. In that time, we have travels thousands of miles in all sorts of weather conditions and on many rough roads.  However, I do still check them often for any signs of loosening.

EternaBond RSW-4-50 RoofSeal Sealant Tape, White - 4" x 50'
Price: $52.14
You save: $27.36 (34 %)
39 new from $44.630 used

Our (walk on capable) fifth wheel roof is covered with 3/8th-inch boarding and the panels are rather lightweight at 16.5 lbs. The 8 screws per panel plus the Dicor sealant seem to be plenty to do the job. But many RV roofs are different and may use much thinner boarding so I’d advise folks to do their homework. Here is an informative article on solar panel mounting by AM Solar. They use a special 3M double-sided tape. I’ve also read of people using well nuts or devices used to hang heavy things on walls.

Running the Wires Down to Charge Controller

I ran the wires for the two new panels in parallel exactly the same as I did in the initial Renogy 200 watt kit installation. I used a pair of Renogy MC4 branch connectors to easily parallel the new panels.

To hold down the wires running across the roof, I again used some 4″ Eternabond tape. It works very well on my rubber roof and makes the install look very tidy I think. Rather than adding a junction box for the parallel wired panels on top of the roof I ran another set of positive and negative extension wires down below following the same path as before.

I did have a bit of a goof up when drilling an extra hole through the roof for the new wires. Doh! See video below for a look.

Then, right near the charge controller input I soldered the wire runs together to form the final single positive and negative connection to the controller. It made the upgrade very easy and kept the wiring at the recommended gauge for the Renogy panels. The wire run from panels to the charge controller is about 15 feet and each pair of two panels is supplied by its own 10 gauge wire pair.

Renogy MC4 Branch Connectors

Renogy MC4 Branch Connectors

My Solar Panel Wiring Diagram
400 Watt Solar Hookup Diagram

More Solar Upgrades Coming Soon

The added panels and batteries are just part of this winter snowbird seasons solar upgrades. With luck, Santa will soon be delivering me a new Trimetric TM2030-RV battery monitor and Bogart SC2030 Charge Controller w/battery temperature sensor. I’ll of course, be detailing the installation of these items and later on how the whole upgraded system performs once we hit the boondocks. Can’t wait!

Video Detailing the Solar Panel Installation

Renogy 400 Watt 12 Volt Monocrystalline Solar Starter Kit with Wanderer
Price: $616.57
You save: $63.42 (9 %)
4 new from $609.991 used from $524.00

See more Mods & Upgrades from Love Your RV!

Upgrading to 400 watts of RV solar power - Love Your RV! blog http://www.loveyourrv.com/ #RVing #Solar

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  • intrepid

    Hi Ray, absolutely enjoy your you tube adventures. My wife and I take notes on places you have been boondocking as next year when we retire we will be doing as much boondocking as we can. Quick question for you, or anyone else who might have some knowledge on this. Lazy Daze with aluminum roof, what is the best way to fasten the solar panels to the roof. Just wondering about galvanizing (?), the electrolytic process that can cause aluminum oxidation when using (for instance) stainless steel screws with aluminum. Is this really a potential problem? Thanks much-love your beagle Angelina Beaglina(?) I grew up with Beagles and adore them. Dave

  • Bruce

    Was there any particular reason you didn’t hook your solar panels up in series paralell and use a MPPT40 controller?

  • chrgrsfan

    Hey Ray, Thanks again on your input on the power converter..got mine coming tomorrow. I also took your advise on the tri-metric 2030 battery monitor after cooking 2 batteries last summer. And like you, I was going to go with the renolgy solar kit but after reading your post on the Bogart controller, I’m convinced on going that way. On the Panels would you of gone a different route if you wouldn’t of already had the 2 renolgy panels already installed or are they sufficient. The price on the renolgy panels are great compared to the Kyocera that Northern Az wind & sun wants. And again.. Thanks for the Help and any other advice you can give..I do appreciate it

    • You’re welcome. 🙂 The Kyocera are very nice, the frames and junction box are a little higher quality but the Renogy were more in our budget. I’m happy with the performance thus far. I’m seeing close to 20 battery charging amps (reported solar output from the Bogart) from the 400 watts (not tilted) during the mid-afternoon sun and it’s only early February now.
      Another reason I liked the smaller 100-watt panels is they were able to fit nicely across the front of my fifth wheel roof. Leaves me lots of space up there still and no shading issues.
      Once I’ve used them through the spring and longer days I’ll be writing up a post with how they performed. Right now we have been off the grid for over 40 straight days so gathering lots of experience.

  • Corrina Kelly

    thanks for the display yet i have a question, why didn’t you just drill thru the roof to come down thru the shortest distance. you seem to waste wire and cut holes that may not be necessary by going in the the stink pipe, down the wall in the bathroom and then head back up to the first compartment in the basement area. that would be somewhere near the solar panels and if your kitchen or door (depending on your layout) could possibly have an area to fish the wires thru. could you offer some continued discussion on your control panel to the inverter and how you actually get to switch from DC to AC within the trailer and not use the generator….thanks for all your help

    • That was the shortest route where I could practically fish the wires. The solar panels are right over the bedroom ceiling and the bed is above the front storage compartment, so I can’t go straight down through my bed.
      My 1000W Inverter is connected to the battery bank, then its AC output is wired into a single outlet near our entertainment center in the living area. When dry camping we make do with just one AC outlet to plug stuff into. We have pretty minimal needs for power, just computers, chargers and the TV.
      If I do want to have all the plugs in the trailer to work I could use the trailers power cord and with an adapter plug it into the inverter and then turn off the charger converters breaker. Some folks wire the inverter into the trailer’s electrical system with the aid of a transfer switch.

  • Mike

    Ray. Love the 200 wt and 400 wt vids and blog. I just purchased the 300 wt kit but upgraded to Renogy’s Adventurer controller. It’s the $80 LCD flush mount. We don’t full time at all and use little as far as appliances. Just the 19 LCD and the furnace in the winter. I have two 6v batteries for a total of 235 amp hrs. I think this will work for us. I was going to buy the 200 wt kit with the tilt mounts but for $60 more I opp-ted for a 3rd panel and will just leave em flat for about the same amps as 200 wt on a tilt. This way I can get about 10-12 amps without fussing with the tilts and that will be plenty for what we do. Anyway just want to say thanks for all the great viewing!

    • Sounds like a great little system Mike! You’re welcome, thanks for visiting!
      I just finished upgrading my original bottom of the line Renogy controller with a unit from Bogart engineering because it works in tandem with their popular Trimetric monitor I also got. Will have a post out soon detailing the install. Santa was good to me this year and early! 🙂