Just my opinion, but SLA is not worth the trouble.Yes many lead batteries need high 14's -even 15V to get to true Full.
FLA usually higher than sealed, and only GEL down below 14V.
Each model has its mfg specs, if the manual / data sheets / tech support are not readily available, not a brand worth buying
Heavy, big, low capacity, saggy...yuck!
I don't need that....not when I have lithium cells.