vexos 1.0.9 uses a different algorithm than versions 1.0.8 and earlier.
8 or less motors are still capped at 2.5A.
9 or more are capped as follow, remember this is current at the motor not current from the battery,
9 2.39A
10 2.29A
11 2.20A
12 2.12A
13 2.04A
14 1.98A
15 1.91A
16 1.85A
17 1.80A
18 1.74A
19 1.69A
20 1.65A
However, those values are only valid if user code has not set current limit lower on one or more motors. If that has happened we take the user specified lower motor current into account and compensate in the calculations accordingly. For example, a situation with a 20 motor drive where 8 of the motors have current limit set very low (say 500mA) allows the remaining 12 motors to all be capped at 2.05A
The algorithm only exists inside vexos at the moment, if I get a chance I will convert to javascript and put up an online calculator or something to make calculations easier.
In addition to the above. In all cases we monitor total battery current. If we see a high current situation for more than 2 seconds, we cap all motors at a lower value, that’s currently 2A for 8 motors or less and 200mA less than the calculated value for 9 or more motors (ie. the 20 motor value would be dropped to 1.45A ). This additional limit is removed when we see the battery current drop.