The first thing I do when I buy a used rig at auction is skip the cosmetics entirely and go straight to the mechanical systems. How a previous owner maintained the furnace, the AC, the water heater — that tells me everything I need to know about how the whole coach was treated. On the Thor Sequence, the 12V electrical system and solar setup is where neglect shows up fast — dead or sulfated batteries, undersized wiring that gets hot to the touch, charge controllers that were never properly configured, and solar panels that look fine on the roof but haven’t pushed a useful amp in years. A failed 12V battery bank doesn’t just mean you’re without lights; it means your slides, your water pump, your furnace ignition, and your refrigerator controls all go down with it, and suddenly a rig that looked like a deal becomes a money pit. I’ve done this upgrade enough times on enough Sequences to know exactly where the system fails and exactly how to fix it right — and that’s what this guide walks you through.
Parts & Tools You’ll Need
- 100Ah LiFePO4 drop-in lithium battery
- Victron SmartSolar MPPT charge controller
- Victron BMV-712 battery monitor
- 40A DC-DC battery-to-battery charger
- 200W flexible solar panel
- ANL fuse holder + 200A fuse
- 4/0 AWG welding cable (battery interconnect)
- Bus bar / power distribution terminal block
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Step-by-Step Repair Guide
Step 1: Diagnose Existing System & Safety Prep
Begin by disconnecting your van’s negative battery terminal and visually inspecting your current 12V electrical system for corrosion, loose connections, and existing charge controller setup. Document all wire gauges, fuse ratings, and component locations, then verify that your Class B van’s chassis can safely support the additional weight of a 100Ah lithium battery (approximately 130 lbs) by checking your floor structure and weight distribution.
Step 2: Install ANL Fuse & Battery Cable
Mount the ANL fuse holder within 18 inches of your lithium battery’s positive terminal using heavy-duty brackets, then install the 200A fuse and connect 4/0 AWG welding cable from the battery positive terminal to the fuse holder. Run the cable from the fuse holder through a protective conduit along your van’s frame to your bus bar location, ensuring it never crosses sharp edges or hot components.
Step 3: Mount Lithium Battery & Bus Bar
Secure your 100Ah LiFePO4 battery in a ventilated, level location using a battery box or secure mounting brackets that prevent movement during vehicle operation. Install your bus bar/power distribution terminal block adjacent to the battery, then connect the positive cable from the ANL fuse to the bus bar’s positive terminal using appropriately sized terminals.
Step 4: Wire DC-DC Charger Connection
Route a dedicated 4/0 AWG cable from your van’s alternator/starter battery through an appropriate DC-DC charger input, maintaining proper gauge for the 40A capacity. Connect the charger output to your bus bar’s positive terminal, allowing your alternator to charge the lithium bank while driving without exposing it to dangerous voltage spikes.
Step 5: Connect Solar Panel to Controller
Mount your 200W flexible solar panel to your van’s roof using adhesive or mechanical fasteners designed for your specific panel model, ensuring proper orientation toward south-facing angles. Run the positive and negative solar leads through conduit to your Victron SmartSolar MPPT controller, connecting them to the designated PV input terminals with appropriate crimped connectors.
Step 6: Install Victron Monitor & Controller
Mount the Victron BMV-712 battery monitor in an accessible interior location and connect its shunt to the negative battery terminal using the included cables, allowing real-time monitoring of voltage, current, and state of charge. Mount your SmartSolar MPPT controller near the bus bar, connect its battery positive/negative terminals to your bus bar, and establish a CANbus connection between both Victron devices using the provided cable.
Step 7: Test System Under Full Load
Reconnect your negative battery terminal, power on all devices, and verify that your BMV-712 displays correct voltage readings (typically 13.2-13.6V) and that the SmartSolar controller shows incoming solar watts. Load test your system by running your van’s 12V appliances (lights, water pump, inverter) for 30 minutes while monitoring the battery monitor’s discharge rate, then recharge using solar and alternator to confirm proper charging operation.
Recommended Parts
| Part | Link |
|---|---|
| 100Ah LiFePO4 drop-in lithium battery | View on Amazon |
| Victron SmartSolar MPPT charge controller | View on Amazon |
| Victron BMV-712 battery monitor | View on Amazon |
| 40A DC-DC battery-to-battery charger | View on Amazon |
| 200W flexible solar panel | View on Amazon |
| ANL fuse holder + 200A fuse | View on Amazon |
| 4/0 AWG welding cable (battery interconnect) | View on Amazon |
| Bus bar / power distribution terminal block | View on Amazon |