Question: what is the difference between 2 gauge and 2/0?
Answer: 2/0 AWG will handle around 190 amps, whereas 2 AWG will handle around 94 amps. This is slightly misleading as the length of the wire must also be considered and the % voltage drop acceptable. For a 3% drop where the load is 20 feet from the battery and you are drawing 100 amps then you would need 2/0.