We installed a full Victron power system in a Gulf Stream BT Touring Cruiser, a B+ or very small Class C, on a mobile job in Tubac, Arizona, about an hour south of Tucson. The system is 400W of solar, a Victron MultiPlus-II 12V 3000VA inverter/charger, an Orion XS DC-DC charger, a Cerbo GX with a touchscreen, a SmartShunt and a Vatrer 12V 300Ah lithium battery. All of it fits under the dinette bench.
Small rigs sound easy. They are not. Less space creates its own problems, and this one had two.
Can you fit a full inverter system in a small Class C?
Yes. This install lives under the dinette bench, and the bench seat goes back over the top. The condition is airflow. A closed compartment with an inverter in it gets hot, so the layout was planned around moving air before any of the equipment was mounted.
The Victron touchscreen is mounted at the dinette, with the Cerbo GX right below it, close enough to keep the data cables short. The customer wanted to keep some room for shoes, so we fit the system to the space instead of taking more of the rig.
How do you keep an RV inverter cool in a closed compartment?
Add fans and tie them to the inverter. We installed an intake fan, an internal exhaust fan and an external exhaust. They are programmed to come on whenever the inverter’s own fan runs, so cool air comes in, the inverter pushes hot air through a clear channel, and the exhaust pulls it out of the rig.
On commissioning day we ran the system hard on purpose to get the inverter warm. The fans kicked in with it, as designed. If you are putting an inverter in a tight bench or cabinet, ventilation is part of the electrical design, not an afterthought.
What replaces the alternator charging relay when you go lithium?
On most Class C and B+ bodies, the alternator charging relay is in the usual spot. Not on this one. We traced the wire back to a 12V power center tucked next to the battery, where you would have to pull the battery just to reset a breaker. There was no room to work in there.
We removed the factory relay and installed a Victron Orion XS DC-DC charger. That lets the alternator charge the lithium battery properly while driving, which is the right way to do it. Lithium should be charged through a DC-DC charger, not straight off the alternator through a relay built for lead-acid.
What solar went on the roof?
400W of Rich Solar panels, wired in series into a Victron SmartSolar MPPT 100/50. The wiring drops down behind the refrigerator, and the solar disconnect is reachable from underneath the bench, because there was no room at the end.
There is also space on the roof for one more panel of about 200W later. It has to be a shorter, wider style than the current panels to fit the open spot, and it would work at about the same voltage. Planning for that now saves rework later.
What battery and DC gear went in?
A Vatrer 12V 300Ah lithium battery. We moved it from the first plan and positioned it so a second battery drops in beside it later, which takes the rig to 600Ah. Off the battery are a Class T fuse, a BEP cutoff switch and a Victron Lynx Distributor, plus a SmartShunt for the battery monitor. The 3000VA MultiPlus-II is single-leg, matched to a 30-amp rig.
The Cerbo GX ties it together with the touchscreen, so the owner can see solar, battery and inverter status in one place. If you want to know how we size a system like this, our guides on how much solar your RV needs and how many lithium batteries to run cover the math.
Why Victron on a small rig?
The Cerbo GX, SmartShunt, MPPT and inverter/charger all report to one screen, which keeps a small install simple to live with. If you are comparing brands, read Victron vs Renogy for RV solar. Tucson RV Solar installs Victron.
How long did it take?
Two days on site: solar and cable runs on day one, then the battery move, fans and commissioning on day two.
What’s next for this rig?
The owner can add a second 300Ah battery and one more panel without redoing anything. That is the point of laying it out right the first time.
Planning a similar install?
We travel to you. Our service areas cover Tucson and Southern Arizona, and this job was an hour south in Tubac. If you are upgrading an older RV, start with our RV lithium battery upgrade page. For another Victron build, see the Newmar Dutch Star install. Before you book, read common RV solar installation mistakes.
Want a Victron system done right on your RV? Call or text Chris at Tucson RV Solar, 520-910-1237, or book at tucsonrvsolar.com/.
