I just recalled that my OnePlus 5 smartphone equipped with an OEM 5V/4A “Dash” Charger, that’s perfectly the same power output as the power adapter of GL-AXT1800, after testing it with my Slate AX, it WORKs !
I also tested it with a USB Hub plugged in and 3 USB dongle drives plugged in the Hub at the same time, all drives are recognized and read/write normally.
Unfortunately, I don’t have a 2.5" external SSD/HDD drive to test with right now to see if the power output is still sufficient for it or not.
Let me find one to test with and report back later.
GL-AXT1800 does not use so much power, I am getting aroung 5-6W while stressing the CPU using this [OpenWrt Wiki] Snippets.
It seems like 2 amp chargers are more than enough if you don’t plan on using USB port on the router.
Tested the following chargers:
Official Rasbperry Pi 4 adapter (KSA-15E) 5.1V 3A - works
Baseus Gan Charger (BS-3915) 65W - works
Baseus Super Si Pro (CCCJG30CE) 30W - works