PCB Design + Firmware for ESP32 Wireless Battery Monitor (2-PCB System)

We are developing a wireless battery monitoring system using two ESP32 modules:

1. Transmitter PCB (placed inside a high-current lithium battery pack):

Measures individual cell voltages (4S–6S, 1.5V–4.2V each)

Monitors internal temperature (resistive thermistor preferred)

Sends data to a nearby receiver via ESP-NOW

Controls three outputs via relays:

Fan ON/OFF

Pulse ON

Pulse OFF (for magnetic latching relay, 5A peak)

2. Receiver PCB (located within 5 meters):

Receives data from the transmitter over ESP-NOW

Displays total voltage, individual cell voltages, and temperature

Uses a 1.8" full-color OLED display

Includes a button to toggle between screen views

Displays a custom logo on the main screen

Deliverables:
Schematics and PCB layout (KiCAD or Altium preferred)

Gerber files, BOM, and pick & place files

Complete firmware for both ESP32 boards

OLED UI logic with screen switching

Low-power sleep mode implementation

Working video showing data transmission and display

Optional (Nice to Have):
Prototyping and shipping of assembled units

Support in selecting an enclosure (waterproof for transmitter, custom for receiver)

Familiarity with battery safety and high-current environments (no current handling required)

Notes:
No need to manage battery charge/discharge paths — this is a sensing-only system.

Your deliverables should be suitable for future mass production.

You must be experienced with ESP32 (including ESP-NOW) and precision analog sensing for battery cells.

Budget:
We are open to milestone-based fixed-price offers.
Phase 1 includes design, firmware, and files ready for fabrication.
Prototyping and enclosure work can be quoted separately.