you get longer out of ya batteries, it dont make any difference to the beam,try it mate you'll be surprised,i have a 14 amp lithium now running a blitz wid a 50 in,my brother lamped off the back of the van one night on his own(both sides of the road)so the light was on pretty much all of the time,we were out about 4/5 hours cant remember exactly and the battery had only used two of the five indicator lights, if yorkshirelad2 can afford it i would go for the lithium.