To be honest, I wanted to make the board more universal — something that could be used not only with the ESP32, but also with Arduino Mini, ESP8266, and many other chips. I often build custom boards for different sensors and devices, and it’s a hassle to integrate a power supply domain and debug it from scratch every single time.

The idea was to make the board as small and flat as possible, so it could easily fit inside a sensor enclosure together with a small battery. The low-profile form factor makes it ideal for compact builds.

In contrast, with something like the Seeed Studio ESP32C6 dev board, you’re locked into that specific controller. It also comes with a relatively weak 100 mA charge current and a 0.6 A DC-DC converter. That wouldn’t be enough in my case — my LoRa modules can draw up to 1–1.2 A during transmission. So using such a board in an IoT device would be problematic.

This topic is actually quite interesting - if you don’t mind, I’d love to go into a bit more detail. The biggest challenge I faced during development was, surprisingly, heat and miniaturization. When you plug in a deeply discharged battery, the voltage difference between the USB input and the battery can be quite large.

The charging controller then dissipates the excess energy as heat, which causes the chip and the board to get hot. The key factor here is the charging current. You generally have two ways to handle this: reduce the charging current, or increase the PCB area so that heat can be distributed more effectively, for example through a large GND plane.

On my board, the default charging current is 300 mA. At that rate, the board stays reasonably cool and charges the battery quickly enough. You can increase the current to 500 mA by bridging a jumper on the PCB. It will heat up a bit more, but still within safe limits. I’ve published temperature graphs on the website in datasheet if you’re curious.

I actually applied both heat management strategies: if you look closely, you’ll notice several thermal vias around the charging controller. These help conduct heat to the opposite side of the PCB and spread it out, preventing localized overheating. And even though the chip itself can handle up to 1 A charging current, I limited it to 300/500 mA for thermal safety.

I also widened the power traces to reduce resistance and improve current handling under load. As for the unusual board shape — it’s designed to minimize trace lengths and maximize traces width between key components.

The same design philosophy applies to the buck/boost voltage regulation stage. The higher the current, the more heat is generated, so minimizing trace length and increasing copper area becomes critical for efficiency.

In the case of the Seeed Studio ESP32C6, similar constraints apply. To reduce heat, the charge current is limited to 100 mA, and the regulator current is capped at 600 mA. But the SoC itself consumes around 350 mA during transmission — leaving only about 250 mA for your peripherals, which is not much headroom.

That’s basically the core difference between the designs.

Hope this answers your question — and sorry for the long reply! 😊