Hi smoline,
Exactly what do you want to run with the larger battery bank? Is it to extend boondocking in "grey day" situations?
Will you be upgrading the inverter to a larger size?
How many watts of solar do you have? Is it possible to beef up the solar by adding more panels?
LI is quite expensive and at least for RV's is the "new kid on the block". You may want to look at Edison batteries instead, which are a mature technology.
LI appears to not do well in cold temperatures. Not only can you not charge them, you can't draw from them either.
