Introduction
In the face of increasing natural disasters such as hurricanes, wildfires, and extreme storms, having a reliable backup power source is essential for safety and comfort. Building a DIY lithium solar generator provides a sustainable, portable, and efficient solution to ensure your critical appliances remain operational during prolonged power outages. This guide offers detailed instructions on creating a robust solar generator housed within a durable Stanley 50-gallon toolbox, combining safety, portability, and high performance.
Step 1: Materials and Components Needed
- Battery Bank: Two high-capacity LifePO4 12V 200Ah lithium batteries (e.g., Aims Power or equivalent). Connecting these in series yields a total voltage of 24V and a combined energy storage of approximately 4800Wh, suitable for heavy-duty backup power.
- Inverter: A 24V 2000W Giandel pure sine wave inverter, equipped with dual outlets positioned externally on the toolbox for easy access. Features include a digital display for monitoring and an on/off switch for convenient control.
- Solar Charge Controller: A high-efficiency 100V input, 24V output, 40A MPPT solar charge controller. This device efficiently manages solar energy input from eight 100W panels configured in a series-parallel setup, ensuring optimal charging without overloading the system.
- Solar Panels: Eight monocrystalline panels rated at 100W each, with each panel producing 18V at 5.6A. Arranged in four series sets of two panels each, then connected in parallel, achieving a nominal voltage of approximately 72V and a maximum power close to 800W.
- DC–to–DC Converter: A 24V to 12V step-down converter, capable of supplying power to multiple accessories such as two 12V ports, two fast-charging USB ports, and dual 120mm cabinet fans, enhancing system versatility.
- Monitoring and Safety Components: Victron SmartShunt for real-time battery monitoring via smartphone, bus bars for efficient connection points, fuses, circuit breakers, and temperature sensors to safeguard system integrity.
- Charging and Power Support: A 120V AC to DC Victron Blue Smart IP67 charger for grid charging, ensuring flexibility in power management.
- Enclosure: The sturdy Stanley 50-gallon toolbox, featuring wheels, an extendable handle, secure latches, and a keyed lock, providing a portable and secure housing for all components. Its weight capacity of 110 pounds comfortably accommodates the entire system.
- Additional Materials: Plywood sheets for mounting bases, T-nuts, screws, fender washers, threaded rods, XT60 connectors, temperature sensors, bus bars, fuses, switches, and other electrical hardware necessary for assembly and wiring.
Step 2: Preparing the Toolbox
Begin by removing the lid and any internal trays from the toolbox to create an open workspace. Using a cardboard template, mark six precise holes in the base to facilitate mounting the plywood platform. Carefully cut out sections of the template to fit around wheel wells and internal raised areas, ensuring a snug fit.
Transfer these marked locations onto a sturdy plywood sheet, then install T-nuts at each point to allow secure fastening. Attach the plywood base to the bottom of the toolbox with appropriate screws and fender washers, ensuring stability. The raised section on the right side of the interior serves to secure the batteries firmly, preventing movement and damage during transportation.
Step 3: Installing the Battery Bank
Position the first lithium battery into the compartment, ensuring it rests securely against the plywood base and the wheel well for added stability. Carefully place the second battery on top, creating a stacked configuration that conserves space. Ensure that both batteries are aligned correctly to facilitate straightforward wiring and component installation, leaving ample room for the charge controller and inverter connections.
Step 4: Mounting the Daughterboard and Critical Components
Cut an additional piece of 3 ¼ inch thick plywood to serve as the daughterboard, which will support essential electronics. Mount the bus bar, circuit breakers, inverter, charge controller, DC–to–DC converter, shunt, and AC–to–DC charger onto this board, ensuring each component is securely fastened for safety and ease of access.
The inverter connects to the battery bank through a 150A circuit breaker, providing overcurrent protection. The charge controller is linked via a 50A circuit breaker, regulating solar input effectively. The bus bar consolidates the positive terminals from the batteries, simplifying wiring complexities and ensuring a clean, organized system. The DC–to–DC converter supplies stable 12V power for auxiliary devices such as USB ports and fans, enhancing overall system functionality.
Ensure all wiring is properly insulated and secured, with attention to safety standards, to prevent shorts or damage during operation or transportation.