The Rockwood Geo Pro and its Flagstaff twin, the E-Pro, are the small trailers people actually boondock in, and the upgrade questions on the Forest River board are the same every season: is the factory solar enough, can I go lithium, and will the truck charge it. Here is the honest version of all three.
What the factory system is
Current models ship with a 200 watt roof panel, a 30 amp charge controller and an 1,800 watt inverter as standard; an optional Power Package adds three 200 watt panels, a 460 amp-hour lithium bank and a 3,000 watt inverter-charger. Older years carried smaller panels and, on many, a PWM controller rather than MPPT. Before you buy anything, read the label on the controller and the converter, because those two decide the whole upgrade.
If the controller is PWM, it throws away the part of the panel's voltage above battery voltage. On a 200 watt panel that is worth ten to thirty percent of the harvest, most of it in the cool mornings and part-shade when you want it most. Our MPPT versus PWM guide explains why.
If the converter has no lithium profile, it will undercharge a lithium battery or, if it has an equalize stage, harm one. Some later WFCO units auto-detect lithium; many earlier ones do not. Our converter upgrade guide covers the check and the swap.
Step one: the MPPT swap
The SmartSolar MPPT 100/30 is the right size for the factory 200 watt panel with room to add a second, and the 100/50 covers three. It fits in the same place as the factory controller, takes the same wires, and adds Bluetooth so you can see what the panel is doing from your phone. Set the battery profile to match the battery you have now, and change it when you go lithium; that is the entire configuration.
Step two: the lithium battery
The Geo Pro carries its battery in a tongue box, and the factory lead-acid group 24 or 27 is the limiting item in the whole trailer. A 280 amp-hour lithium in the same box is roughly five times the usable energy, and its low-temperature protection matters on a trailer that gets used in shoulder seasons. Two checks before ordering:
- Box dimensions. Measure the tongue box inside; a metal-case 280 Ah is bigger than a group 27. Confirm it fits with the lid closed.
- Tongue weight. The battery is heavier than the lead-acid it replaces. Weigh the tongue afterwards and confirm it is still inside the range for your hitch and the trailer's rating.
Fit a SmartShunt on the battery negative at the same time. Lithium holds its voltage flat until it is nearly empty, so the factory voltage gauge will read "full" all the way down; the shunt gives you the real percentage, in the same app as the MPPT. Our 280 Ah install guide covers the wiring and fusing; a lithium battery needs a fuse at its terminal with an interrupt rating to match, and a MEGA fuse on the branch circuits.
Step three: will the truck charge it
Through the 7-pin, a little. The truck's charge line is a 10 or 12 gauge wire behind a 30 amp fuse, and after twenty feet of voltage drop it will trickle a lead-acid and barely touch a lithium. A DC-DC charger in the tongue box, fed from that line, turns the trickle into a regulated charge at whatever the line can supply, typically 15 to 20 amps, and the Orion XS can have its input limit set to exactly that in the app. For the full 50 amps you run a dedicated cable from the truck battery to an Anderson plug at the bumper, which is a bigger job and worth it only if you drive between camps a lot. Our guide to charging a lithium camper from a truck's 7-pin covers the arithmetic, written for electric trucks but the same for any tow vehicle.
The order that works
- Read the controller and converter labels.
- MPPT swap, and a second panel if the roof has room.
- Converter with a lithium profile, if yours lacks one.
- Lithium battery, SmartShunt, fuse at the terminal.
- DC-DC charger in the tongue box if you want the truck's help.
Each step works on its own and none of them has to be undone for the next. Send us your model year and a photo of the controller and converter labels and we will tell you which steps apply. Everything ships from Upland, California.