BMS 3S 20A Lithium Battery Protection Board for 18650 Cells

The BMS 3S 20A Lithium Battery Protection Board is a battery management circuit built to protect packs made from three 18650 lithium cells connected in series. It manages charging and discharging so your pack stays safe and lasts longer, making it a popular choice for DIY power banks, solar storage builds, small pumps, LED lighting, and hobby and electronics projects around the home, farm, or workshop.

Key features

• Designed for 3S packs — three 18650 lithium cells in series.
• Rated for up to 20A current, suitable for everyday DIY loads.
• Helps protect against overcharge, over-discharge, and short circuit.
• Compact board that fits neatly inside most battery enclosures.
• Standard solder pads for easy wiring to your cells and load.

Typical uses

• Building or repairing 18650 lithium battery packs.
• DIY power banks and portable power boxes.
• Small solar storage and off-grid lighting setups.
• Hobby robotics, electronics, and maker projects.

How to choose / tips

Match the board to your pack configuration: this one is for 3S (three cells in series). Make sure your total load current stays within the 20A rating, and always pair healthy, balanced cells of the same type. Keep your wiring clean and insulated for a safe, reliable build.

Why tna W rna

At tna W rna we focus on dependable parts and reliable sourcing. Enjoy fast delivery across Egypt and the convenience of cash on delivery, so you can build your projects with confidence.