Hello,
We are planning to use ESP32-POE or ESP32-POE-ISO as our control system for our upcoming products. Data sheet says it can provide 4 watts of power. Most of our sensors need 5 Watts of power.
As we understand SI3402 can provide 13+ Watts. What is bottleneck? Is there anyplace on board where we can solder wire and pull more power? We don't need regulated 5V or 3.3V power, we have switching regulator in our sensors that can accept 3.3V to 48V input.
What you wrote about Si3402 is true, and we have a PoE extractor with the same chip that can provide up to 10W without any issues: https://www.olimex.com/Products/Modules/Ethernet/MOD-POE-V2/
However, ESP32-PoE and ESP32-PoE-ISO are another story. There is no way to increase the wattage available, it is what it is written and we have tested it a lot of times. There are two main reasons for it - the small PCB size and distance between components might hinder heat dissipation, the on-board peripherals consume a lot of power themselves.
My advice is to either search for another product or power an ESP32 board and your sensors from a separate PoE extractor.