ESP32 Wireless Battery Monitor – Firmware and PCB Design

I’m building a wireless battery monitoring system using two ESP32 modules. One module will be inside a lithium battery pack (4s–6s configuration) and the other will be in an external display box. These modules will communicate using ESP-NOW.

The system should display total voltage and temperature on a 1.8" full-color OLED. A button press should show individual cell voltages. There will be no charging or discharging through the PCB.

This job is for firmware and hardware design. Mass production support is optional.

Project Details:

PCB 1 (Transmitter - inside battery):

Read voltage from 4s–6s lithium battery cells

Read temperature using 10K NTC (3950) sensor

Send data wirelessly using ESP-NOW

Control 2 relays (fan + ON/OFF)

RGB LED indicator output

No current sensing, no charge/discharge routing

PCB 2 (Receiver with display):

Receive data via ESP-NOW

Display total voltage + temperature and logo on home screen

Show individual cell voltages on second screen (button press)

1.8" full-color OLED display

Powered by Li-ion cell + USB-C charging

RGB LED and momentary button input

What I Need from You:

Firmware for both ESP32s (ESP-NOW, OLED UI, relay and LED control)

Schematic + PCB design in Altium (or similar)

BOM with component sources

Breadboard demo (photo or video is fine)

Optional:

Gerber and pick-and-place files

PCB prototype manufacturing (e.g. through JLCPCB)

Mass production or enclosure support

Timeline:
I would like the breadboard demo and design files within 2–3 weeks.

How to Apply:

1. Share past work involving ESP32, ESP-NOW, and PCB design

2. Confirm experience with OLED displays and Altium/KiCAD

3. Mention if you can support optional manufacturing

Budget:
Please send separate pricing for:

1. Firmware + PCB Design + BOM

2. Breadboard Demo

3. Optional production support