This is the bare PCB you need to build your own 26mm FET or FET + 7135 driver!
This PCB allows for quite a few options---many of which are optional. It can be run in normal single-cell configuration, zener mod configuration for 2S-4S cells, or with an LDO voltage regulator for 2S-4S cells and momentary use.
This PCB also has optional provisions for an integrated temperature sensor and PWM output for powering other boards (custom firmware required).
Parts Required (1S Cell):
- FET: LFPAK56 N-Channel Mosfet
- 7135
- D1: SOD-323 or 0805 Schottky diode
- C1: 10uF MLC capacitor, 0805 (X6S or X7R preferred)
- R1: 19.1K, 1% resistor, 0805
- R2: 4.7K, 1% resistor, 0805
- UI: ATTINY13A MCU, SSH or SSU variant
- Spring / LED leads
- OTC: 1uF MLC capacitor, 0805 (X7R preferred)
- Pad with side closest to MCU can also be used as electronic switch pad (no OTC installed).
Parts Required (2S-4S Cells - Zener Modified):
- FET: LFPAK56 N-Channel Mosfet
- D1: 200 ohm 0805 resistor
- C2: 10uF MLC capacitor, 0805 (X6S or X7R preferred)
- R1: 36K, 1% resistor, 0805
- R2: 4.7K, 1% resistor, 0805
- Zener Diode: SOD-123 4.3-5.1v
- UI: ATTINY13A MCU, SSH or SSU variant
- Spring / LED leads
- OTC: 1uF MLC capacitor, 0805 (X7R preferred)
- Pad with side closest to MCU can also be used as electronic switch pad (no OTC installed). ELECTRONIC SWITCH NOT RECOMMENDED WITH ZENER MOD. LDO PREFERRED.
Parts Required (2S-4S Cells - LDO):
- FET: LFPAK56 N-Channel Mosfet
- D1: EMPTY
- C1: 10uF MLC capacitor (rated higher than input voltage), 0805 (X6S or X7R preferred)
- C2: 10uF MLC capacitor, 0805 (X7R preferred)
- LDO: SOT-23-5 such as AP2204
- R1: 36K, 1% resistor, 0805
- R2: 4.7K, 1% resistor, 0805
- UI: ATTINY13A MCU, SSH or SSU variant
- Spring / LED leads
- OTC:
- Pad with side closest to MCU can also be used as electronic switch pad (no OTC installed). Clicky switch usage not recommended with LDO option.