This is what you need to look at.
You need to know the distance between your battery and converter, and converter amp output. I highly doubt 10 gauge is close to ok. With my new converter, I got 4 gauge wire from Greg's marine wire supply online. Remember, if you battery is fairly low, you can have a lot of current going to it.
I emailed progressive dynamics about it:
"Yes the wire should be rated for the full amperage of the converter and fuse (which should be close to the battery to protect the wire) whichever is higher.
I cannot recomend wire sizes due to liability issues.
Wires should be sized according to the RVIA / NEC codes.
For a rough guide see:
for voltage drops using different
gauges verses distance/load
P.S. 2/0 or 4/0 is much larger than the 2 gauge you mentioned. It starts with the higher the number, the thinner the wire. When you hit 0 and go to the x/0 sizes, the larger the number, the bigger.