Monthly Archives: November 2021

4 cell 18650 DIY PCB

4 Cell PCB loaded with 2.6Ahr Lithium Ion cells

Lithium batteries have overtaken all other batteries as the technology to use for most electronics projects. Lithium wins with energy density (size), longer life and good power outputs. There are also other positives for the technology.

However Lithium cells are not always as easy to use as the older Ni-Cd, Ni-NM cells and SLA (Seal Lead Acid) batteries. The reason is Lithium cells need to be voltage balanced when charging. Failure to do so reduces the life as one or more cells can become unbalanced and overcharged. Over charging can also lead to fires in extreme cases. Lithium cells can also be damaged if discharged too low. Recharging lithium batteries that have dropped below 2.5V can also be dangerous if precautions are not taken.

This board is ideal for prototyping in projects. It has a Battery Management System (BMS) that protects the cells from over charging and over discharging. It also balances the cells. Just install 4 18650 cells and you are ready to go. No having to spot weld cells into packs!

The board contains a 40A BMS, however as it’s designed to use with ‘standard’ non high discharge cells so 5 amps is the maximum recommended discharge rate.

4 Cell BMS Board

Off the shelf BMS on back


Battery Type18650 Lithium Ion
PCB Size100 x 92mm
Nominal Voltage14.4V (3.6V per cell)
Fuse5 A
Under Voltage ProtectionYes < 10V
Over voltage ProtectionYes > 16.8V

Bare and populated PCB’s can be ordered, email

18650 Cells

I use and stock the LG Chem LGABB41865 Cells. These are standard discharge rate 2.6Ahr cells, with a max discharge rate is 5A (5 to 45Deg C ambient temperature). See datasheet for normal charging and discharging rates. These are perfect for general projects, however can not be used in high discharge motor applications like power tools. For this high-discharge Lithium Ion cells are required.

I stock LG Chem LGABB41865 Cells in Adelaide for locals, however I will not ship these interstate.

New LG Chem 2.6Ahr Lithium Cells