In a fuel tank system for a vehicle, the fuel tank system having multiple independent tanks fluidly connected to a single fuel filling port on the vehicle, and a T-connector for directing the fuel to the multiple tanks. The fuel filling port is fluidly connected to the tanks through the T-connector, which is configured to direct the fuel to one of tanks until that tank is filled, and then to divert the fuel to the second tank. The second tank includes a vapor vent, and both tanks are connected by a vapor line, the vapor venting system configured so that a nozzle shut-off back pressure is not developed until the second tank is filled to its fill line. The configuration of the dual tanks and their fluid connection to the fuel inlet port allows the tanks to be substantially filled independently of relative fill levels between tanks, fuel and ambient temperature, fuel reid vapor pressure, or vehicle attitude.