Likely a starting battery. 2x GC2 would provide 220Ah.
For minimum gen time with a Li battery you need a good charger that's designed for Li. Flooded battery chargers are 3 stage and many hours are required to fully charge plus best if only discharged to 50%. Li can be discharged to 20% or even lower. Then with a compatible charger they can take the full charge to 100%.
WFCO are well known to not charger to the absorb state (about 14.4V) so sure they will charger a Li overnight for example. There may be some models and/or installations that do better so understand what you have and what you want to accomplish.