Before make a purchasing power supply decision, do you consider power efficiency and size? higher efficiency can save energy and electric charge, at the same time smaller size not only easy to take but also save more shipping cost.
As far as large power supply of over 600W, efficiency and size is more important than small and middle power adapter.

Efficiency=Pout/Pin*100%, Pout=Vout*Iout.
Take S1200 as samples, Pout=24V*50A=1200W
If efficiency=94%, means consumptive energy is 72W; it is is 90%, the wasteful energy will be 120W.

Model:S1200

Chargery S1200 user's manual (179K)

1. AC90 ~ 265V input, world wide safety operation
2. Active PFC: PF>0.99 at 90VAC, 100% of load
3. DC11.5V ~ 24.5V output adjustable for most of applications
4. Up to 94% of efficiency at 80% of load and AC220V
5. Digital display output voltage and current on time.
6. Over current, over voltage, over load and over temperature protection. Resume automatically when troubleshooting.
7. Short-circuit protection on output, safer and more reliable.
8. 3 Intelligent cooling fans turned on at over 50℃
9. 3 outputs can do more chargers or other DC powered device simultaneously.
10. Warranty of 24 months.