Repairing ANOTHER "Professional" Victron Off Grid Power System

Overview

A van came in for minor exterior work, but inspection revealed serious problems with its “professional” Victron off-grid electrical installation. The presenter documents the faults, then reorganizes and reconfigures the system.

Problems Found

• Battery wiring and monitoring: The two 12 V lithium batteries were connected in parallel with system takeoffs arranged in a way that could cause uneven charging and discharging. The solar controller’s negative connection also bypassed the shunt, making battery readings inaccurate.
• Missing or questionable protection: The batteries had no individual fuses. Some cable connections were loose or incorrectly assembled, including a washer placed under a cable lug.
• Undersized cables: The inverter wiring was too small for a 3 kVA MultiPlus. The presenter replaced it with 4/0 cable, in line with the cited Victron recommendations.
• Poor component placement and ventilation: The MultiPlus was resting on the floor, with one side’s ventilation obstructed. The DC-DC charger and other equipment were poorly oriented or crowded, with little ventilation around the heater and electrical gear.
• Untidy wiring: Small wires and circuits were bundled haphazardly, making the system difficult to service.
• Incorrect configuration: The BlueSolar MPPT was set to AGM rather than lithium. The MultiPlus charging current was set to 90 A; the presenter increased it to 120 A.
• Unsafe, damaged roof wiring: The old solar array consisted of four 25 W panels attached to a rail, and the wiring insulation was damaged.

Repairs and Improvements

• Rewired and organized the system using 4/0 cable, a distribution arrangement with a modified Lynx component, a main switch, and 150 A MRBF fuses for each battery.
• Repositioned the DC-DC charger vertically and mounted the MultiPlus off the floor to allow airflow. The presenter noted that additional fans could improve ventilation, but there wasn’t time to install them.
• Added a clearly marked switch for the battery heating elements and connected the BMS so it can disconnect the charger.
• Programmed the BlueSolar MPPT for lithium using a VE.Direct-to-USB adapter and a computer, since this model lacks Bluetooth.
• Replaced the old roof array with a 100 W Rich Solar panel. The presenter connected the existing 12 AWG cable to 10 AWG wiring and MC4 connectors, while noting that the 12 AWG run would ideally be replaced. There is space for another panel, but the small charge controller limits expansion.

Battery Capacity and Runtime

The batteries were initially mistaken for 200 Ah units, but the presenter later identified them as two 100 Ah batteries, for 200 Ah total at 12 V. Based on an estimated 40–50 A draw, a 12 V air conditioner could run for roughly four hours without recharging.

The presenter suggests that the owner may need a broader redesign if adding more solar or upgrading the system.

Guide and Tutorial Points

The video is a practical inspection and repair walkthrough covering battery-parallel wiring, shunt placement, fusing, cable sizing, ventilation, and lithium charge-controller configuration. It also demonstrates why system monitoring can be inaccurate when charging sources bypass the shunt.

Main speaker and source: The Fenix Off Grid Solutions presenter, who inspects and repairs the van’s electrical system. The van owner is discussed but does not provide a substantial on-camera account.