My Driver station idea is similar to this robot cart and I came up with the idea of having an onboard mcu monitoring all the charge levels and everything. This will have relays to be able to turn on and off things like inverters. I thought of this idea just while writing this:
Measure, using a multimeter how much current the inverter draws in standby (no load). Have the MCU power down the inverter if it doesn't notice a load for a couple minutes and a button to reactivate it. That will feed you with more hours. Also, plug in the robot cart when at the pits or near a power plug. That will make sure that you can get the longes runtime, and that will also give the battery some rest. Also, if a team is ready to spend a thousand dollars, check this out:
http://www.howellenergy.en.alibaba.c...tery_Pack.html