Got the battery. There goes $110. Didn't have 6 gauge cables on hand at this store but had 4 gauge out the ying yang. Does it matter on gauge? I know how the numbers work. Big #, small wire. Small #, big wire.
What D'Chill said. I told you 6 gauge because they'd be cheaper and I know you don't have bigger going to your TM. In all reality, for a 2' length carrying 12v, 10 gauge will work, but in a marine environment we always want more than just "that will work". We want overkill wherever possible. 4 gauge is way better.
I will also make sure you have a fuse in line somewhere so that will go before your TM
that charger will work for two 12v wired in series too. Basic electrical theory