Honda EU1000i Owner's Manual page 38

OPERATION
Disconnecting the battery charging cable (optional equipment):
1.Stop the engine.
2.Disconnect the black lead of the battery charging cable from the 
negative (–) battery terminal.
3.Disconnect the red lead of the battery charging cable from the 
positive (+) battery terminal.
4.Disconnect the battery charging cable from the DC receptacle of the
generator.
5.Connect the vehicle battery ground cable to the negative (–) battery
terminal.
36
BATTERY CHARGING CABLE
(optional equipment)
BLACK LEAD
RED LEAD