Complete repair guide for the Winnebago Solis – 12V Lithium Battery Bank & Solar Upgrade. Follow these steps to diagnose and fix the issue yourself.
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 Electrical System
You’ll need to assess your current 12V system by checking the existing battery type, capacity, and condition using a multimeter to record baseline voltage readings. Document all current loads, wiring gauge, and fuse ratings to ensure your new lithium system can safely handle your power demands and existing accessories.
Step 2: Disconnect Battery and Isolate Power
You must disconnect the negative terminal of your existing battery first, then wait at least 15 minutes for all systems to discharge before proceeding. Cover the battery terminal with electrical tape to prevent accidental reconnection during the upgrade process.
Step 3: Install ANL Fuse Holder Assembly
You’ll mount the ANL fuse holder directly near the positive terminal of your new LiFePO4 battery, using the 4/0 AWG welding cable to create a secure connection. Insert the 200A ANL fuse into the holder and ensure it clicks firmly into place, as this protects your entire electrical system from short circuits.
Step 4: Route Battery Interconnect Cabling
You should run your 4/0 AWG welding cable from the fused ANL holder through your vehicle’s existing cable conduit or protective loom to reach your electrical distribution point. Keep the cable away from heat sources, sharp edges, and moving parts by securing it with adhesive-backed cable clips every 12-18 inches.
Step 5: Connect Bus Bar and Charge Controller
You’ll attach the positive and negative cables from your LiFePO4 battery to the bus bar terminal block, then connect your Victron SmartSolar MPPT controller inputs directly to the battery terminals. Mount the charge controller in a well-ventilated location away from moisture and ensure all connections are hand-tight before final verification.
Step 6: Install Solar Panel and Battery Monitor
You’ll secure your 200W flexible solar panel to your Winnebago’s roof using adhesive backing or mechanical fasteners, then route the panel wiring to your MPPT controller with proper strain relief. Install the Victron BMV-712 battery monitor in your living space where you can easily view it, connecting the shunt in series with your negative battery cable.
Step 7: Test System Operation and Monitor Readings
You should reconnect the negative battery terminal and power on your new system, checking that the Victron display shows proper voltage (typically 13.6V for lithium) and that the solar panel is charging. Monitor your battery percentage, amp-hours, and system voltages for 24 hours to confirm all components are communicating correctly before returning to regular use.
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 |