Intact Lithium Battery
The cheapest and easiest way to save the most weight is with the battery. Another advantage is the much smaller discharge and more constant starting current of a lithium battery. If you don't ride that often or just go to the track a few times a year, you won't want to be plugging in the battery all the time. Intact is known from racing with its own Moto2 team where Dominique Aegerter rides in MotoE.
The optimal charger for these batteries can be ordered. Attention not every charger can also charge lithium batteries.
The 48 Wh is basically enough for the recommended bike, but there is the possibility to install a battery with more energy output, all three batteries are exactly the same size.
Technical details:
LI-0412,8V, 4Ah, 48Wh, 240A, 1.1kg
LxWxH: 148x86x105 mm
Japan Code: LTM14
Replacement for: YTZ12S = GEL12-12Z-S, YTZ14S = GEL12-14Z-S, YTX12-BS = 51012, YTX12A-BS = 51013, YTX14-BS = 51214, YTX14H-BS, HVT-08
LI-0512.8V, 5Ah, 60Wh, 280A, 1.3kg
LxWxH: 148x86x105 mm
Japan Code: LTM18
Replacement for: YTX16-BS = 81600, YTX16-BS-1 = 81601, YB16B-A = 51615, YB16B-A1, HYB16A-AB = 51617, YB16-B = 51912, YB16-B-CX, YB16C-B, YB18-A = 51816
LI-0612.8V, 6Ah, 72Wh, 330A, 1.5kg
LxWxH: 148x86x105 mm
Japan Code: LTM21L
Replacement for: YTX20L-BS = 82000, YTX20HL-BS = 82003, YTX24HL-BS = 82400, Y50-N18L-A-CX, Y50-N18L-A = 52012, Y50N18L-A2 = 52012, Y50N18L-A3 = 52012, SY50-N18L-AT = 52012, HVT-03