I have created a race timing system which uses a POE RFID reader and a POE hat on a Raspberry Pi 4. I want to be able to power the systems out 'in the field' using a 12v Leisure battery with a 12v POE injector. I need a recommendation for a managed switch and whether it requires a 12v-24v or 12v-48v converter/injector. Thanks in advance for your help, im pretty new to POE but love what its capable of.
The basic PoE IEEE 802.3af standard is supporting PoE Type 1 (Class 0..3), extended PoE+ IEEE 802.3at is supporting Type 1 and Type 2 (Class 0..4), and the once more extended IEEE 802.3bt standard does support Type 1, 2, 3 (max. 60W per port, Class 0...6) respectively Type 1, 2, 3 and 4 (max. 100W per port, Class 0..8) - all numbers power infos apply to the PSE end (switch, injector). On the devices there will be guaranteed 12.95W (Type 1), 25.4W (Type 2), 51W (Type 3) und 71W (Type 4) available. Be aware it's what the PoE-add-ons do request during the handshake, not the plain math what the devices are using.
Be aware the IEEE PoE standard require the PSE supplying 44...57V (PoE), 50...57V (PoE+), and 52...57V - thus higher voltage power supplies are kind of a standard.
