The best replacement for fuel tank is fuel cell.

The best alternatives to fuel tank are rated as following:
★★★★★  fuel cell
★★★  pedal power 2
★★  dc brick
★  voodoo lab
  pedal power

Your alternative for fuel tank is not listed? Suggest!
Speaking about fuel tank, one probably shouldn't forget about tool box.

Other search terms related to fuel tank and their ratings are:
★★★★★ tool box
★★ toolbox
★★ tool box for pickup
You have in mind a companion for fuel tank and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of fuel tank in all years. Click on graph for more.
fuel tank
fuel cell
pedal power 2