"MegaPack" a 12V 5200mAh Battery Pack
Introduction: "MegaPack" a 12V 5200mAh Battery Pack
Hey, guys what's up!
So this is "MegaPack" a 12V Li-ion Battery Pack made in an exciting form factor.
I used PCBs with Li-ion cell Holders to make a simple PCB that holds Cells in a neat way, it has an OnBoard BMS which controls the charge and discharge cycle of the battery pack.
I've also added a Buck Converter to the one side of the PCB that outputs stable 5V for powering XYZ Arduino projects.
This article is about the whole built process of this Battery pack so let's get started!
Supplies
These are things I used in this built-
* Custom PCBs
* Li-ion cells
* BMS 11.1V 3S
* Li-ion Cell holder SMD Version
* DC Jack
* MPS2314
* 10K Resistor
* 10R Resistor
* 7.5K Resistor
* 75K Resistor
* 40K Resistor
* 100uf Capacitor
* 10uf Capacitor
* 1H inductor
* Slide switch
* USB Port
* LED
* M7 Diode
* PCB Standoffs
Step 1: Specs
Here are a few specs and features of this Battery Pack.
* 11.1V 5.2Ah Battery Pack with BMS for charging and discharging without damaging the battery from overcharge and over-discharge.
* I've added a Buck Converter circuit on this setup that bucks down 11.1V from the battery pack and convert it into stable 5V 2A Output through the USB Port.
* Charging time is usually 5-6 Hours if we use a 12V 1A Adaptor.
Step 2: Schematic
So Above is the Schematic I prepared, it consists of a total of 6 Cells connected in a 3S 2P configuration, (S is series and P is parallel).
I connected Li-ion cells with the BMS in the right arrangement, Output of this battery pack is given by BMS, on the BMS there are certain MOSFETs and BMS Ics that monitor each cell voltage, if the voltage gets lower than the cell over-discharge rate which is 2.5 for each cell, it shuts down the output so we cant drain the cells up to 0V, if we drain the cell lower than 2.5V, Its capacity will be affected and it won't work properly later. BMS makes sure that each cell is charged properly which is 4.2V and stops the discharge at 2.5V.
I added a DC Barrel Jack with a Mosfet for charging the battery pack and also added the MPS2314 Circuit.
MPS2314 is a synchronous rectified step-down switch mode converter IC that offers 2A continuous output current over a wide input supply range with excellent load and line regulation, I've set its voltage under 5V which is enough to power USB Devices like an Arduino board for example.
Step 3: PCB Design
After finalizing the schematic, I converted it into PCB File and prepared a Rectangular board in which I added an SMD Li-ion Cell holder on one side, BMS is placed near the Cell holder and an MPS2314 setup has been placed on one side.
I've added three more Cell holders at the bottom side of the board.
I added holes at all four sides, my plan is to add PCB Standoffs with these holes and attach another PCB at the end side to make a sandwich layout.
By this method, we dont have to prepare a casing or enclosure for this Battery Pack, its PCB is itself the body.
After completing the routing, I exported the Gerber data and sent it to PCBWAY for samples.
Step 4: PCBWAY
I received the PCBs in a week which was fast.
I choose Blue Soldermask for this project with a white silkscreen and the overall quality of the PCBs was just awesome.
I have Been using their service for a while and I have to say, it's pretty decent for getting started.
Checkout PCBWAY from here- https://www.pcbway.com/
Step 5: PCB ASSY
PCB Assembly of this project contains the following steps that also include testing the board before adding components on the bottom side.
* Solder paste Dispensing
* Pick & Place Process
* Hotplate reflow process
* Adding THT components and Cells holder on the Bottom side
* Testing Process
Step 6: SOLDER PASTE DISPENSING
I first added solder paste to each component Pad with a solder paste dispenser. 267