The VB electrical system is pretty simple… There are distinct AC and DC systems which do not intersect.

The only things that run on AC power are the air conditioner, the battery charger and any other devices you plug into the two AC outlets. There is no inverter, so to use any AC power you need to be plugged into shore power.

  • The Air Conditioner is a relatively standard window unit that typically draws ~5–7 amps while running, and up to 10–12 amps briefly at startup (compressor kick-on).
  • The battery charger will use up to 1.9amps during it’s bulk charging phase which lasts no longer than 7 hours if the battery is fully depleted.

The DC system is powered by the battery and runs all the 12v devices: the Dometic cooler/fridge, MaxxFan ventilation fan, and the lights. The system is protected by a main 25amp fuse as well as individual 10- or 5-amp fuses for each circuit. Typically, we see that people are easily able to run these items for a long weekend on a single Lithium battery charge. Charging the battery can be done with:

  • AC powered battery charger – up to 15amps/hr
  • the rooftop solar panels – 160watts – in Minnesota, 4.5–5.5 peak sun hours per day, 75–85% of theoretical = 62Ah × 0.8 ≈ 50Ah per day
  • stand alone Zamp/GoPower Panels
  • DC/DC charger while driving – 6-7amps/hr while driving

Rough estimates of DC power usage:

  • Dometic CFX5 35 At 75°F ambient, set around 37–40°F: Compressor draw (when running):~4.5A
  • Duty cycle at 75°F Typically 25–35%, Average hourly draw: 4.5A × 0.30 ≈ 1.35A average,Daily fridge consumption:1.35A × 24h ≈ 32Ah per day in moderate weather.
  • MaxxFan Usage, Overnight Medium ≈ 1amp× 8h = 8Ah, Daytime Low ≈ 0.2–0.3A × 16h ≈ 4Ah, total per 24h: 8 + 4 = 12Ah

If you are plugged into shore power/solar generator the battery will always be charging, there isn’t an easy way to avoid this (other than unplugging the battery charger) so when running the Airconditioner from your generator the generator will also be charging the battery.

Power loads in the trailer

12V DC DEVICES (Battery Powered)

  • Dometic CFX5 35 Running draw: ~4.5A Average at 75°F: 1.2–1.5A Daily use: ~30–35Ah
  • MaxxFan Deluxe Speed/Amps Low 0.2–0.3A, Medium ~1A, High 2–3A
  • LED Lighting – Cabin/galley/mood lights (each) ~0.1–0.4A
  • Water Pump 4–7A while running, Only runs intermittently, Daily average typically <1Ah unless heavy use
  • Propex Heatsource (Propane heat, but blower is electric) 1.5–2A while running, about 10 min/hour @30 dgrees
  • 12V Socket / USB Outlets -Phone charging: 0.5–1A per device while charging
  • Propane / CO detectors Always-On Background Loads, ~2–3Ah/day

120V AC DEVICES (Shore Power Only)

  • Air Conditioner Running: 5–7A @120V, Startup surge: 10–12A, ~600–800 watts running, Cannot run on battery
  •  Victron Blue Smart IP65 Charger, Outputs 15A @ 12V (180W) ~1.8A @120V max
  • Standard AC Outlets, whatever you plug in

Charging Sources

  • 160W Rooftop Solar Panel – Peak output: 160W, Real world daily: 40–55Ah (sunny MN summer)
  • Controlled by: Victron SmartSolar MPPT 75/15 Up to 15A charge current to battery
  • Victron Orion-Tr Smart DC-DC Charger 6-8A typical while towing