Is anyone running a Skyrc D100 charger with 200w DC input?

I have been running it AC/DC for now, but looking to get a PSU to be able to charge 1/8 batteries faster. I know the charger can handle 2x 10A with a 200w DC input but I'm a little confused by what it says on the charger:

DC input: 200w
max 250w

Please correct me if I am wrong, but this is my logic:
Input voltage is 11-18v, so if I want use the charger at 20A does that mean I can only use a psu that can provide 20A at ~11-12V? (12vx20A= 240w). If that's the case I'm probably screwed out of buying a decently priced psu as most of them seem to have a fixed voltage of 13.8 or 15v. I know the higher priced psu's have controllable voltage but I was looking at the more moderately priced ones.

Any thoughts?

It is not wise to choose a PSU rated to the maximum load of the charger, I would say the 250w is recomended.

But power is not about the PSU but the load that the charger will make. If you charge 500mA mini drone batteries you can use a 20 watt power supply. But if you connect a 1000 watt supply the charger will not be blown up, the charger will only take what it needs.

I would recommend used server PSU, 10-25Euro, 15 minutes of soldering. I use Delta Electronics DPS-600RB, 12V output, 600W, 49A max.

Get one of these. Cheap, anvil-esque reliability, more power than you will ever need, and cheap. Also, they're cheap.