Saturday, September 30, 2023


These new portable solar panels are the cat’s meow!    

I was recently asked to review the new E.FLEX portable solar panels from Renogy. As someone who spends most of their time dry camping, I jumped at the chance. Since a good percentage of my generator’s run time is to charge my house batteries, having an efficient solar system to charge them will greatly reduce my dependence on my generator. Since these are portable solar panels, I can position them for maximum exposure. Being portable also allows me to park my RV in the shade to keep cool during the summer months while leaving the panels in full sun.

The new E.FLEX portable solar panels are manufactured from advanced materials, allowing them to be more efficient, compact, and lighter weight than other portable solar panels. The folding design allows them to be stored just about anywhere. The manufacturer promotes them as a high-performance charging solution for the off-grid lifestyle.

More technical details from their press release go on to say, “The new E.FLEX Portable Solar Panel series has superior PERC monocrystalline solar cell technology with a conversion efficiency of up to 22%. They are IP67-rated water-resistant and feature durable ETFE surfaces for a longer lifespan, improved light transmittance, scratch resistance, and low-maintenance cleaning.”

I was sent the E.FLEX 120 panels along with a Rover series controller to review.

Set up and first impressions of these portable solar panels

I was going to use the word “installation” in the above heading, but given these are portable solar panels, there isn’t much to install. Since I wanted to “play around” with the system, I didn’t want to permanently mount the charge controller until I understand the nuances of maximizing the system.

Instead of mounting the controller, I installed a short two-plug pigtail connected to the house batteries. I then connected the mating half to the charge controller. This allows me to connect the controller directly to the house batteries with a minimal length of wire (i.e., no voltage drop concerns). When in use, I just let the controller sit atop the A-frame of the trailer, allowing me to easily monitor the charge rate while outside with the panels. I then mounted (tightened two screws) the leads connecting the portable solar panels to the controller. Note: There is a red O-ring on one of the leads which I mistook as a sign of positive polarity. It is actually the negative lead. Polarity is marked positive and negative on the mating ends of the connectors of the solar panels.

Safety note: Always connect the battery terminal wires to the charge controller FIRST, then connect the portable solar panels to the charge controller. NEVER connect the portable solar panels to the charge controller before the battery.

Home test

Once I had everything connected, I performed an “at-home” test of the system. Note: The charge controller automatically recognizes the battery voltage (12V or 24V) when energized, eliminating the need to set the voltage manually.

The next step is programming the battery type via the charge controller by toggling the operating keys. Choose between flooded lead acid, sealed lead-acid, gel or lithium. Regardless of battery type, they must be deep cycle. Note: The icons for the battery types are very small and difficult to see for those of us with corrective eyewear. This is about the only improvement I can suggest to the product at this time.

Then set the charging parameters via the “USER” mode on the controller. Charge settings include Equalizing voltage, Boost voltage, Over-discharge voltage, Over-discharge return voltage and Float voltage. Note: The charge controller manual includes a table listing Battery Charging Parameters.

Once programmed, I set the portable solar panels in the sun to experiment with the system. The screen on the charge controller allows the user to view Charging Current, Battery Voltage, Battery Capacity (state of charge), Accumulated AH (amp hours) and more. By turning on different 12-volt items in my RV, I was able to place various loads on my battery bank, which caused the solar system to respond accordingly.

Once the home test was completed, I stowed the panels in the included zippered water-resistant carrying case. The case provides easy transportation and storage of the folding panels, which conveniently fit under the lift bed in my RV. With the system tested and stowed, I was ready for a field test.

E.FLEX Portable solar panels
E.FLEX panels at bottom of photo folded up and ready to be put in the storage case at top of photo. Photo by Dave Helgeson

Field test

With favorable spring weather predicted, my wife and I drove our RV into Eastern Washington, where the sun always shines. Since the daytime temperatures were only predicted in the mid-70s, we chose a campsite in full sun. Once the RV was parked, I hooked up the controller to my house batteries via the plug noted above and then connected the portable solar panels. Once connected, the controller indicated my house batteries were at 100%. This was thanks to the alternator on my truck, a DC to DC charger on the tongue of my travel trailer and driving 100 miles.

Portable solar panels and RV
E.FLEX potable solar panels deployed and soaking up the afternoon sun – Photo by Dave Helgeson

I left the system in place while we used the RV until sunset. The house batteries never fell under 100% state of charge. That night we used multiple ceiling lights, the water pump, and other 12-volt items before going to bed. The furnace ran multiple times during the night, bringing down the state of charge (S.O.C) of the house batteries a fair amount.

Time to shine!

With the house batteries drawn down, it was time to really test the E.FLEX portable solar panels.

Potable solar panels
Capturing the morning sun. Note the long shadow indicating low sun angle – Photo by Dave Helgeson

The next morning, as the sun rose above the distant hills, I quickly deployed the controller and portable solar panels. The integrated kickstand on the back of the panel allowed me to position them for maximum exposure. Even with the low morning sun angle, the system was soon showing a charge rate of more than 6 amps into my house battery bank. Given the draw down from the night before, my batteries eagerly accepted the incoming charge as the controller recorded the amp hours (AH) delivered back into the batteries. Impressive!

Solar controller
Nice morning charge! Photo by Dave Helgeson

My initial impression of the E.FLEX portable solar panels? It is a great system for those looking to camp off-grid and keep their house batteries charged. It’s lightweight, compact, and easy to hook up and store.

Later this summer my wife and I will be embarking on a 2-week boondocking trip into the wilds of Idaho. The E.FLEX portable solar panels will be going along and I look forward to seeing how the system will perform during an extended period off-grid. I expect to be running the generator a whole lot less! Stay tuned for a follow-up article.

Specifications of the RENOGY E.FLEX portable solar panels:


  • 24.8 x 17.1 x 1.0 inches when folded
  • 7.3 lbs.
  • 80W maximum power at STC
  • 17.2V optimum operating voltage (VmP)
  • 20.7V open circuit voltage (Voc)

E.FLEX 120

  • 26.4 x 21.7 x 1.0 inches when folded
  • 11.0 lbs.
  • 120W maximum power at STC
  • 19.8V optimum operating voltage (VmP)
  • 23.8V open circuit voltage (Voc)

And, lastly, the E.FLEX 220

  • 29.1 x 22.9 x 1.6 inches when folded
  • 20.4 lbs.
  • 220W maximum power at STC
  • 22.7V optimum operating voltage (VmP)
  • 26.8V open circuit voltage (Voc)

The E.FLEX Portable Solar Panel series is available now on the Renogy web store. Learn more by clicking here.

Click here to learn more about solar and buying tips from’s own Dustin Simpson.

Dave will be speaking at the 2023 America’s Largest RV Show in Hershey, PA, September 13th – 17th. He would love to meet readers that are attending. Feel free to introduce yourself after one of his seminars.


Dave Helgeson
Dave Helgeson
Dave Helgeson has been around travel trailers his entire life. His grandparents and father owned an RV dealership long before the term “RV” had been coined. He has served in every position of an RV dealership with the exception of bookkeeping. Dave served as President of a local chapter of the RVDA (Recreational Vehicle Dealers Association), was on the board of advisors for the RV Technician Program of a local technical college and was a board member of the Manufactured Home and RV Association. He and his wife Cheri operated their own RV dealership for many years and for the past 29 years have managed RV shows. Dave presents seminars at RV shows across the country and was referred to as "The foremost expert on boondocking" by the late Gary Bunzer, "The RV Doctor". Dave and his wife are currently on their fifth travel trailer with Dave doing all the service, repair and modifications on his own unit.


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2 months ago

Good setup, but I would be concerned about them being taken by someone! Nice controller with all battery settings, also panels seem to have gone down in price!

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