The ProVari version 1 had a 2.5 amp limit, same as the original L-Rider Lavatube. ProVari version 2 has a 3.5 amp limit.
The BuzzPro has an upper limit of 15 watts. At its max voltage of 5.5 volts, that's only 2.72 amps, but, because it a switching regulator, that means bursts up to 3.13 amps, with an average of about 3.0 amps (according to Buzzkill, the BP's creator).
Those numbers remain the same with different juices or cartos.