I've taken the batteries out of the trailer and managed them in the garage since we bought it. The 2/12/70 has kept the grp 27 happy all this time but I wouldn't trust it on my big bank. That bank chewed up and spit out a Megawatt and would do so again without a lot of mods to it. I'll go with the 120a version of what BFL is using since it is made to take it and won't need a 10 hour run of the generator if I ever did get the bank down to 12.0v.
Right now the big bank lives in the Expy until the solar is mounted to take care of it. There is a 230w panel up top of the truck that keeps the bank up and the charge controller can be set to match the manufactures specs for the most part.
I had two Schumackers but the 2/10/50 started charging everything at 15 volts one day.