Originally published on zampsolar.com and updated with Keystone’s SolarFlex packages. Zamp Solar is now part of Go Power!, a Dometic company, and our North American team supports Zamp Solar products.
Keystone RV has built solar into its travel trailers and fifth wheels since the 2020 model year: first with the OTG (Off The Grid) package on Cougar, Passport and Bullet, then with SolarFlex, which Keystone now factory-installs across its towables. Every one of these systems includes a Zamp Solar portable charge port, so owners can add portable solar without new wiring. This guide covers what each package includes and how to add to it.
Keystone OTG (2020–2021 models)
Keystone RV’s OTG, or Off The Grid, package was the completely engineered OEM solar power system owners had been waiting for. The number one goal with this factory option was to eliminate the trial and error of sourcing an aftermarket solar power solution. It was available on Cougar, Cougar Half-Ton, Passport and Bullet RVs in two configurations: the OTG Solar Prep (solar pre-wired) or the OTG Solar Camping Package (170 watt panel and 30 amp charge controller installed).
What is the OTG Solar Prep?
Because these Keystone Bullet, Passport and Cougar models came equipped with an expandable Zamp Solar 2-port roof cap, owners save time and money when they decide to take things to the next level and upgrade their solar capacity. Travel trailers and fifth wheels with OTG prep include factory wiring for up to three Zamp Solar Legacy 170 watt solar panels, or 510 total watts on the roof.
OTG prep also includes a Zamp Solar sidewall port for OBSIDIAN® Series portable solar panels, connections for batteries located in the pass-through storage, and up to five outlets prepped for an inverter, depending on the model. With OTG prep, you have the flexibility to pick the aftermarket components that meet your specific needs.
OTG Solar Prep standard components (pre-wired for Zamp Solar):
- Dual-port roof cap, with the solar charger prep located in the pass-through storage compartment for easy access.
- Sidewall port for portable solar panel systems.
- Inverter wiring prep, located in the pass-through storage compartment. The inverter is NOT included and is not necessary for solar charging.
Factory-installed OTG Solar Camping Package
With Keystone’s optional OTG package, owners receive components handpicked by the Keystone engineering team for their compatibility and quality. You also get the added assurance of an installation that is integrated into the build process and done by a team that is intimately familiar with the trailer. An inverter is optional and is not necessary for the solar charging system to work properly. The package includes:
- One (1) 170 watt Zamp Solar roof-mounted solar panel, expandable up to 510 watts with aftermarket equipment
- One (1) 30 amp Zamp Solar charging system
“I love solving these fundamental industry problems every day and allowing campers to have a better experience…”
— John Brock, Keystone R&D Engineer
Keystone SolarFlex (2022 and newer)
SolarFlex replaced OTG and is factory-installed on Keystone fifth wheels and travel trailers. Every SolarFlex package has 30 amp solar roof ports with solar connectors (SC), up to two panels per roof port, and a Zamp Solar portable solar charge port. Packages are monitored from a phone app.
2022–2023 SolarFlex packages
| Package | Roof solar | Charge controller | Inverter | Battery | Keystone models |
|---|---|---|---|---|---|
| SolarFlex 200 | 200W (1 panel) | 15A MPPT | Prep for up to 7 outlets, inverter not included | Not included | Alpine, Arcadia, Avalanche, Bullet, Carbon, Cougar, Fuzion, Hideout, Montana, Outback, Passport, Premier, Raptor, Springdale, Sprinter |
| SolarFlex 400i | 400W (2 panels) | 30A MPPT | 2000W with built-in transfer switch | Not included; battery monitor included | Alpine, Arcadia, Avalanche, Bullet, Carbon, Cougar, Fuzion, Montana, Outback, Passport, Premier, Raptor, Sprinter |
| SolarFlex 600i-L | 600W or 660W (2 panels, varies by build date) | 50A MPPT | 3000W inverter/charger with built-in transfer switch | 270Ah heated lithium | Alpine, Arcadia, Avalanche, Carbon, Cougar, Fuzion, Raptor |
| SolarFlex 1200i-L | 1,200W to 1,320W (4 panels) | Two 50A MPPT | 3000W inverter/charger, all outlets inverted | Two 270Ah heated lithium (540Ah) | Montana only |
The 600i-L and 1200i-L also include soft-start air conditioners that can run on solar and battery power.
Current SolarFlex packages
- SolarFlex Ready: no solar installed, but the trailer is prepped so solar can be added later.
- SolarFlex Protect 220: 220 watts of roof solar, prepped for an inverter to be added later.
- SolarFlex Discover 440i: 440 watts of roof solar, a 2000 watt inverter and a smart battery monitor.
- SolarFlex Outlast 660i-L: 660 watts of roof solar and a 270Ah lithium battery.
- SolarFlex Outlast Extreme 1320i-L: 1,320 watts of roof solar and two 270Ah lithium batteries.
For full specs by model, see Keystone’s SolarFlex page.
Adding to your Keystone solar system
The original Keystone OTG upgrade kits are no longer sold, but OTG and SolarFlex trailers can both build on their factory systems:
- Add portable solar: both our DuraLite portable kits and legacy portable kits work with Keystone trailers. Plug into the factory Zamp Solar port and park the panels in the sun while the trailer stays in the shade.
- Add roof solar: the Go Power! 200W Overlander black solar kit is the roof upgrade for Keystone trailers.
- Upgrade an OTG charge controller: if your trailer came with a Zamp Solar PWM controller, see Upgrade Your Factory PWM to MPPT.
- Replacement parts and mounting hardware: shop Zamp Solar parts and accessories.
Not sure what your trailer has? Contact our support team with your model and year, and we’ll help you sort it out.