Lithium batteries drastically longer cycle life over a lead-acid, 4-5x service life over lead-acid. This means you would get 5-7 years out of a lead-acid battery but would get 20 yrs out of lithium (keeping all other factors equal).
Improved charge technology, halve your generator run
time, reap the fuel savings!
No maintenance, no fluids, no worries
Incredible energy density in a lightweight package