I purchased a victron 75 | 15 solar charge controller, I have it connected to a 100w solar panel from ecoflow, then connected to 12v 36ah lipo4 battery. The load wires are wired up to a 12v to 24v step up converter and then in a barrel jack plugged into a poe injector. The poe injector is showing a green light but I'm not getting any power to the acces point I'm trying to power. Any ideas what I might be missing, first time messing with diy solar. 
The solar side of things looks like it's working fine, the panel and battery voltages etc. And the light on the POE injector would imply it is working. Do you have a multimeter you can check the voltage on the network cable going into the AP? And then work your way back along the line to the POE injector and then the 12 to 24V convertor. Something is not getting the voltage it needs.
I assume you just have a "missmatch" between the PoE-Injector and the PoE-driven AccessPoint.
Most (modern) AccessPoints require PoE++ , while cheapish PoE-Injectors just provide PoE or PoE+ at best...
Have a look at the manuals if you find anything mentioned for either device.
https://www.black-box.de/en-de/page/23894/Resources/Technical-Resources/Black-Box-Explains/Networking/PoE-in-Networking/
