said by elios:
the power Powerlab6 is 1000watt and 8 is 1344watt
but they ether need to be run off a set of deep cycle Pb cell batteries or a 24v to 30v bench supply
OK, I had a look at the Powerlab and it is supposed to charge multiple packs in parallel with taps coming from each pack using separate 9-pin connectors.
Instead of a 30V/50A bench supply, which will be really expensive, consider my original suggestion of an adjustable 24V AC-DC module from Vicor, TDK-Lambda, etc.
Set the output to match maximum safe voltage rating of the Powerlab.