© Copyright 2026. All Rights Reserved
3S 40A BMS Board – 11.1V 12.6V 18650 Li-ion Protection
Availability:
In stock
Rs.210.00
3S 40A BMS Board – Protection and Balancing for 12V 18650 Lithium Packs
This 3S 40A BMS board protects a three-cell 18650 lithium-ion pack that runs at 11.1V nominal and charges to 12.6V. It guards the cells against overcharge, over-discharge and overcurrent, and its balancing function helps keep the three cells at similar voltages. The board is a bare PCB that you solder into your own pack, so it suits makers, repair technicians and small-project builders. Use it to build a safer 12V battery for LED lighting, standby electronics, small inverters and solar lamp projects. Choose cells that can supply the current your load needs.
Key Features
- 3S configuration: Designed for three lithium-ion or LiPo cells in series, giving 11.1V nominal and 12.6V at full charge.
- Overcharge protection: Stops charging when a cell reaches its limit, which helps prevent damage from overcharging.
- Over-discharge protection: Disconnects the load when a cell voltage falls too low, protecting the cells from deep discharge.
- Overcurrent protection: Cuts the output if the load draws too much current.
- Cell balancing: Helps keep the three cells at similar voltages. It works best when the cells are well matched.
- Up to 40A discharge rating: A high current rating for demanding loads, provided your cells and cooling can support it.
- Solder-in installation: Connect to the pack taps at 0V, 4.2V, 8.4V and 12.6V following the wiring diagram.
Technical Specifications
| Product Name | 3S 40A BMS Lithium Battery Protection Board |
|---|---|
| Cell Configuration | 3S (three cells in series) |
| Cell Type | 3.6V / 3.7V lithium-ion or LiPo, such as 18650 |
| Nominal Pack Voltage | 11.1V |
| Full-Charge Voltage | 12.6V |
| Maximum Discharge Current | 40A |
| Protection Functions | Overcharge, over-discharge, overcurrent |
| Cell Balancing | Yes |
| Connection Points | 0V, 4.2V, 8.4V, 12.6V taps |
| Installation | Soldering required |
Applications
This 3S BMS board suits small 12V lithium packs built from 18650 cells. Typical uses include LED lighting, standby and backup power for electronics, small inverters and solar street lamp packs. It also suits repair work and DIY battery projects. For high-current tools such as drills, the cells must be rated to deliver the current, because the BMS only limits current and does not create it.
Package Contents
- 1 × 3S 40A BMS protection board
Frequently Asked Questions
How many cells does this board support?
It is for three lithium-ion or LiPo cells in series (3S), such as three 18650 cells. Full charge is 12.6V.
Can I use it with LiFePO4 batteries?
No. The board is designed for lithium-ion cells that charge to 4.2V each (12.6V for the pack). LiFePO4 cells need a different BMS.
How do I connect it?
Soldering is required. Connect the 0V, 4.2V, 8.4V and 12.6V taps exactly as shown in the wiring diagram, and check every connection before charging. For the main 0V and 12.6V leads, use copper wire rather than nickel strip.
Can I run a power drill from this board?
Only with cells rated for high discharge current. Ordinary 18650 cells may not be able to supply high current, so check the cell datasheet first.
Why does the board get warm?
The balancing circuit can warm up while it evens out cell voltages, especially during the first charge. If it becomes very hot, check your wiring and reduce the load.
Order from Electronics Hub Pakistan
Looking for a 3S 40A BMS board in Pakistan? Explore our range of BMS and Battery Management boards at Electronics Hub. Check the cell count, current rating and wiring diagram against your battery pack before ordering, and pair the board with suitable 18650 cells and a matching 12.6V charger. Order your 3S 40A BMS board today and build your 12V lithium pack with confidence.