Overview: Solar & The Cargo Conversion Series

This new series will be a lot of fun. I’m going to share what I’ve learned as a general overview on the process of building 4 different solar systems. I’ve gone from a full DIY piecemeal system to high end Victron Energy system. Along the way I’ve made quite a few mistakes and found all the ways to NOT do it. In this series I’ll share my experiences and what my idea of an ultimate mobile off-grid system is. Hint: the old axiom of “You get what you pay for!” might be true in solar builds!

Who’s it for?

The series is aimed at someone who has never dug into building an off-grid solar system but would like to. If you are looking to build a cargo trailer conversion, are just getting started with full-time RV’ing and planning on putting in a new solar system or just wondering what the process is for installing an off-grid solar system then this is for you. It would also serve as a checklist for someone getting their ducks in a row for a new install.

Here’s a rundown of what I have planned for this series:

1. Planning & System Design

Determine power needs (daily watt-hours or amp-hours)
Create a usage profile (lights, fridge, fans, etc.)
Choose system type:
- Modular system (separate components)
- All-in-one power station (integrated battery, inverter, and controller)
Decide on DC vs AC loads
Sketch wiring diagram or system layout (if not all-in-one)
Choose fixed vs portable solar panels

2. Battery Bank

For modular systems:
- Battery type: AGM, Gel, Lithium (LiFePO4), Lead Acid
- Sizing: Capacity (Ah), voltage (12V, 24V, 48V)
- Battery monitor/BMS
For all-in-one systems:
- Check built-in battery specs (capacity, chemistry)
- Expandability options (some allow extra battery packs)

3. Solar Panels

Type: Monocrystalline, Polycrystalline, Bifacial, Thin Film
Wattage and number of panels
Fixed vs portable panels
Compatibility with charge controller or all-in-one unit
Input voltage/amperage limits for all-in-one systems

4. Charge Controller

For modular systems:
- Type: PWM vs MPPT
- Sizing (amps, volts), safety features
For all-in-one systems:
- Built-in MPPT controller (usually optimized and pre-configured)
- Input range compatibility with chosen panels

5. Inverter

For modular systems:
- Pure sine wave vs modified sine wave
- Wattage and surge capacity
- Standalone or inverter-charger combo
For all-in-one systems:
- Built-in inverter (check AC wattage output)
- Pass-through charging support for use while charging

6. Wiring & Connectors

For modular systems:
- Wire gauge based on load and distance
- Fuse blocks, breakers, MC4 connectors
- Proper crimping, routing, and protection (conduit, loom)
For all-in-one systems:
- Pre-wired internally
- Minimal external wiring (solar input, optional DC/AC output wiring)
- Plug-and-play connectors for solar and expansion batteries

7. Mounting Hardware & Installation

Solar panel mounts (roof, tilting, folding suitcase-style)
Battery boxes or secured compartments (modular)
Mounting brackets for inverter/controller (if separate)
Dedicated location for all-in-one system (secured, ventilated)

8. Safety & Grounding

Fuses, breakers, and disconnects for modular setups
System grounding (panels, controller, battery frame)
Built-in protection for all-in-one units (typically includes BMS, over-voltage, short-circuit protection)
Surge protection and fire safety prep

9. Tools & Equipment Needed

For modular builds:
- Multimeter, wire stripper/crimper, torque wrench
- Drill, fasteners, heat shrink, terminal tools
For all-in-one systems:
- Minimal tools—often plug-and-play
- Tools mostly needed for mounting solar panels or optional expansion wiring

10. Monitoring & Management

Modular systems:
- Separate battery monitor (Victron, Renogy)
- Charge controller and inverter displays
All-in-one systems:
- Integrated display panels
- Mobile apps for Bluetooth/Wi-Fi monitoring
- Smart features (load optimization, timers)