12V Li-Ion Battery for Heavy Loads

This 12V battery is constructed from used 18650 cells, configured in a 3S5P arrangement, with a total capacity ranging from 10 to 15 Ah depending on the specific cells. It features a 20A Battery Management System (BMS) for charging, but the discharge path bypasses the BMS due to the high inrush current of certain loads, such as diesel heaters or motors.

Important: Users must carefully monitor the battery to prevent overload or over-discharge. The built-in voltmeter assists in this monitoring.

Assembly Steps:

• Print the 3D parts.
• Prepare the aluminum plate by cutting it to the dimensions specified in the drawing.
• Assemble the case by gluing the bent aluminum plate to the bottom 3D part.
• Build the 3S5P cell pack, ensuring all cell voltages are equal before connecting them in parallel.
• Create electrical connections using brass strips if spot-welding equipment is unavailable.
• Finalize wiring for the BMS and voltmeter.

Safety: The battery is safe when charged and discharged solely through the 5.5mm power socket. A 50-100A fuse must be installed for short-circuit protection.