V4
stuartpittaway·diyBMSv4·ModuleV400/v4.kicad_pcb
About the V4 PCB
V4 is an open source AVR/Arduino PCB design by stuartpittaway, published on GitHub under the CC-BY-NC-4.0 license. It is a 2-layer board measuring 30 × 50 mm, with 38 components from 28 distinct parts.
Its main chip is the ATtiny841-SSU, from the AVR/Arduino family. Other key parts include the HMHA2801. By type, the board carries 23 resistors, 4 diodes, 3 LEDs, 3 capacitors, 2 ICs and 1 transistor.
It belongs with the power & battery designs in this gallery.
From the project
Version 4 of the diyBMS
Do it yourself battery management system for Lithium ion battery packs/cells
More discussion Open Energy Monitor Forum
If you are looking for version 3 (obsolete) of this project take a look here
THIS REPOSITORY CONTAINS THE HARDWARE FOR THE SYSTEM
If you order a PCB, please use my affiliate link to help support this project JLCPCB
If you find the BMS useful, please consider buying me a beer, check out Patron for more information

Main components on the V4
V4 bill of materials (BOM)
38 components, 28 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | HMHA2801 | SOP-4_4.4x2.8mm_Pitch1.27mm | U1 |
| 1 | ATtiny841-SSU | SOIC-14_3.9x8.7mm_Pitch1.27mm | U4 |
| 1 | IRLML6244TRPBF | SOT-23 | Q1 |
| 1 | AVR-ISP-6 | Pin_Header_Straight_2x03_Pitch2.54mm | J2 |
| 1 | Remote temp input 47K @ 25oC | Pin_Header_Straight_1x05_Pitch2.54mm | SENSOR1 |
| 1 | Battery | JST_PH_S2B-PH-K_02x2.00mm_Angled | POWER1 |
| 1 | RX Connector | JST_PH_S2B-PH-K_02x2.00mm_Angled | RX1 |
| 1 | TX Connector | JST_PH_S2B-PH-K_02x2.00mm_Angled | TX1 |
| 1 | LM4040BIM3-2.0/NOPB, 2.048V, SOT-23-3 | SOT-23 | D1 |
| 1 | Blue | LED_0805 | D2 |
| 1 | RED LED | LED_0805_HandSoldering | D3 |
| 1 | Green | LED_0805_HandSoldering | D4 |
| 1 | 100nF | C_0805_HandSoldering | C1 |
| 1 | 2.2uF | C_0805_HandSoldering | C2 |
| 1 | 10uF 10V | C_0805_HandSoldering | C3 |
| 1 | 10K | R_0805_HandSoldering | R1 |
| 1 | 1K | R_0805_HandSoldering | R2 |
| 1 | 475K E96 series (tolerance 1%) | R_0805_HandSoldering | R3 |
| 1 | 402K E96 series (tolerance 1%) | R_0805_HandSoldering | R4 |
| 1 | 220R | R_0805_HandSoldering | R5 |
Show 8 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 8 | 2R2 1W | R_2512 | R6, R7, R8, R9, R10, R11, R12, R13 |
| 1 | 510R | R_0805_HandSoldering | R14 |
| 3 | 47K | R_0805_HandSoldering | R15, R20, R21 |
| 1 | 4K7 | R_0805_HandSoldering | R16 |
| 2 | 2K2 | R_0805_HandSoldering | R17, R18 |
| 1 | SDNT2012X473F4150FTF | R_0805_HandSoldering | R19 |
| 1 | 10R | R_Axial_Power_L25.0mm_W9.0mm_P27.94mm | R22 |
| 1 | 2K2 | R_0805 | R23 |
V4 design files
The KiCad project lives in the stuartpittaway/diyBMSv4 repository on GitHub; these links point at the commit this page was built from.
V4: common questions
What microcontroller does the V4 use?
The V4 is built around the ATtiny841-SSU, from the AVR/Arduino family.
How big is the V4 PCB?
The V4 measures 30 × 50 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the V4?
38 components, from 28 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the V4 design files?
From the stuartpittaway/diyBMSv4 repository on GitHub, which has the KiCad layout and the BOM; the links under Design files point to each one.
Can I use the V4 design in my own project?
It is published under CC-BY-NC-4.0, which limits how it may be reused; read the license before building on it.
Can I test firmware for the V4 without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.
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