look its safer to use lead acid batterys than lithium on a bike..... ive have spent time around lithium batteries and i can tell if the battery goes pop which is more a question of when not if..... the lituim would literal melt you skin off through your bike gear trust me it aint pretty....... oh look my hand dissovled.
the attached photo is from a 1.2amp lithium battery
think about the burns you would get of a 10-20amp lithium battery
dont risk it just get your self a lead battery and replace it when you need to