Monster 659 Owner's Manual page 87

Disconnect the quick-release fittings (18) from the flange.
E Remove the elastic retaining strap (19), remove the caps
from the terminals, unscrew the screws (22) on terminal
clamps (20) and (21), always starting with the negative
terminal, then remove the battery from its seating.
86
18
21
22
19
fig. 82
20
fig. 83