Not a hope on hell would it ever be close to 2 or 3 volts at the pump.
Use the formula and do the math.
V = (25 x I x L)/CM
eg Use 28/030 cable, lets say 20 feet should be plenty, of stranded copper wire(thinwall) will carry continuously 25 amps or roughly double the pumps max will result in a resistance of 0.0536, and a volt drop after 20 feet of 0.6968 volts.
This is influenced by temperature, current carried(amps) material conducting and length.
Steel ie car body has a resistance of 0.00684 ohms/foot, resistivity ohm/cm of 11.8
copper has a resistance of 0.000999 resistivity ohm/cm of 1.725, so steel is OVER SIX times as resistive to current flow.
These are at 25C by the way better conductors than steel include ohm/cm,
platinum 10.0
iron 10.0
nickel 7.8
brass 7.0
iridium 5.29
aluminum 2.828
gold 2.44
copper 1.724
silver 1.629
All again at 77F
tabetha