[Jonny H]

The cooling output is variable depending on what speed the ECU drives the compressor - the max input power on the standard settings is around 1000W. The compressor is rated 2600W cooling capacity.

From our install manual:

ECU

ElectroCooler’s ECU provides the necessary control to regulate the compressor speed in accordance to the power available from the charging system. Without the ECU, the compressor could run beyond the means of the alternator which would result in a flat battery. Either that, or the compressor would be run too slow and compromise the A/C performance.
The ECU contains an algorithm that adjusts the compressor speed (and thus current) based on alternator output, battery voltage, driving conditions and a number of other factors.