sup guys, i recently started working at an industrial hydraulic shop and have been introduced to a whole new world of hydraulics. therefor i have discovered hydraulic pumps that run off of the engine instead of running powerpacks with tons of batterys. so what i am asking is am i the first to discover this ( probably not) or is there a reason that everyone continues to use powerpack pumps. i realize that the one disadvantage to this is the vehicle has to be running to do anything but other than that what are some of the pros and cons to this style of set up??