The Protec does ony 50 watt per channel, with 4S you wll charge with only 3A
The Hitek dos 100 per channel so you can charge 4S with 6A but.....
Total Charge Circuit Power: 100 Watts AC Input / 200 Watts DC Input
If you want to use full capacity of that charger you need to use an external DC power supply. And wgwn looking arround for an AC/DC charger you will see more like those limited specs when using it on AC.
But there are some large recent topics about chargers, look them up!