I don't have lithium, but i dont think there will be any problem
the avg generator can be started with a motor cycle battery
they just happen to be connected to larger batteries in an RV
your (2) battle born, should have no problem starting your generator
when i had a low 6v house batteries
i started the onan with a little portable lithium jump starter
i even started this Ford 460 with it, then went to the store and bought a new chassis battery
lithium has tremendous surge current capabilities, despite the conservative rating they have speced it at
most starters most of the time, do not draw near the CCA rating of the batteries or starter
i doubt the generator starter draws more than 80amps
look on the web, at all the 'go carts' kids toys, made use a car starter and one battery and the hours of run time they get before recharge
ratings are for worst case scenario, cold very tight engine
if you ever have a problem, start the drive engine, then hold the emg start button while starting the genny
