2 layers88.8 × 76 mm
2 layers83.1 × 40.6 mm
12v autocut charger
ANSHUMANDOCX/AutoCut-ChargerIts a Autocut charger to charge a 12v Lead Acid Battery
- Size
- 83.1 × 40.6 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 23
- Nets
- 16
- Pads
- 59
- Tracks, vias
- 87, 54
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 24 Jan 2026
- Updated
- 22 Mar 2026
Overview
12v autocut charger is an open-source printed circuit board by ANSHUMANDOCX, from the ANSHUMANDOCX/AutoCut-Charger repository on GitHub. It is a 2-layer board of 83.1 × 40.6 mm with 23 parts on 16 nets, routed with 87 tracks and 54 vias.
It is built around the BC547 and MJE2955. Its parts include 5 resistors, 5 diodes, 4 capacitors, 2 transistors and 2 connectors. It belongs with the power boards of this library.
Main components
2README
README.mdAutoCut-Charger
Plan
This board is designed for trickle charging a lead acid battery and turn of the charging automatically once it reaches the max rated voltage of the battery automatically. the cutoff voltage can be set using the trim pot.
How to use
Its pretty simple to use we just need to connect a 12-0-12 transformer to the circuit and the ac voltage will be rectified from Full bridge rectifier then using RV1 we set the output voltage and measure it using a multimeter one we are at it then we will use the rv2 to set the cutoff voltage we will know that we are at the cutoff when we will see the full led turned on and the relay clicks.
Connection Guide
The connections are pretty straight froward the 12-0-12 from the center tap transformer goes to the 3 pin terminal of the PCB and the battery +ve and -ve is connected to the 2 pin terminal on the labelled pins
Parts Requried
- 12-0-12 transformer
- 12v relay
- LM317t voltage regulator
- MJE2955 transistor
PCB and Schematic and CAD
BOM
| Name | Qty | Vendor | Price ($) |
|---|---|---|---|
| ALL BOM parts mosfet,resistor capacitors etc | LCSC | 14 | |
| 12-0-12 3A | 1 | ROBU | 6 |
| PCB | JLCPCB | 5 | |
| Total | 25 |
Parts
23| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 1000uF | Capacitor_THT:CP_Radial_D10.0mm_P5.00mm | C1, C2 |
| 2 | 10K | Potentiometer_THT:Potentiometer_Bourns_3296W_Vertical | RV1, RV2 |
| 1 | 100nf | Capacitor_THT:C_Rect_L7.2mm_W2.5mm_P5.00mm | C3 |
| 1 | 10A | Diode_THT:D_P600_R-6_P20.00mm_Horizontal | D3 |
| 1 | 10K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3 |
| 1 | 10R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1 |
| 1 | 10uF | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | C4 |
| 1 | 1K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R4 |
| 1 | 220R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R2 |
| 1 | BC547 | Package_TO_SOT_THT:TO-92_Inline | Q2 |
| 1 | CHRG | LED_THT:LED_D3.0mm | D4 |
| 1 | Conn_01x02_Socket | TerminalBlock:TerminalBlock_MaiXu_MX126-5.0-02P_1x02_P5.00mm | J2 |
| 1 | Conn_01x03_Socket | TerminalBlock:TerminalBlock_MaiXu_MX126-5.0-03P_1x03_P5.00mm | J1 |
| 1 | D | Diode_THT:D_DO-41_SOD81_P10.16mm_Horizontal | D2 |
| 1 | FULL | LED_THT:LED_D3.0mm | D5 |
| 1 | G5LE-1 | Relay_THT:Relay_SPDT_Omron-G5LE-1 | K1 |
| 1 | GBU1508A-B1-0000 | easyeda2kicad:GBU_4P-L22.0-W3.6-P5.08 | D1 |
| 1 | LM317_TO-220 | Package_TO_SOT_THT:TO-220-3_Vertical | U1 |
| 1 | MJE2955 | Package_TO_SOT_THT:TO-220-3_Vertical | Q1 |
| 1 | R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R5 |
| 1 | RESTART | Button_Switch_THT:SW_PUSH_6mm | SW1 |
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Questions
How big is the 12v autocut charger PCB?
It measures 83.1 × 40.6 mm and has 2 copper layers, 1.6 mm thick.
What parts does the 12v autocut charger use?
23 parts, built around the BC547 and MJE2955. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the 12v autocut charger KiCad files?
From the ANSHUMANDOCX/AutoCut-Charger repository on GitHub, at the commit this page was made from: the board is PCB/12v autocut charger.kicad_pcb and its schematic PCB/12v autocut charger.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the 12v autocut charger design in my own project?
Its repository states no licence, so its author keeps all rights: ask ANSHUMANDOCX before reusing the design.