Hey There. I Wonder why Victron Page does not recommend me the 250 Blue Solar.
I am Planing to run it with 20 of JA Solar JAM54D41/430Wp
If I get the data Sheets Right, it is ~15 A Open circuit and 38,5 V
If I place them in 5 Series and 4 parallel.
192 Volt and ~60 amps. Shouldn‘t the mppt be able to handle ?
Please help my stucked Brain. 
This really depends on what your system DC battery voltage is…
for 48V nominal, you have 180A of potential charge current from you solar modules.
The MPPT amp ratings are DC output, not PV input.
You also need to take into account any cold temperature (<25C) change to the Voc of the strings.
so for a 48V system, you would need 2 off MPPT 250/100 chargers.
for a 24V system, this current doubles…
Hope this helps.
Did you select oversizing above 130%?
If I select those panels in that config, it’s oversized by 176%. 2x MPPTs could be a better solution depending on what you’re trying to accomplish.
Depending on your lowest temperature, if you’re going to use 1 MPPT, you should consider 4 strings of 5 panels. Saves you some wiring.