Yamaha JWX-1 Owner's Manual page 58

If you mishandle either of these batteries or their chargers, it may result in heat generation,
rupture, electric shock, or injury. Be sure to adhere to the items below.
Do not short the terminals
of the battery with wires
or other metals. Always
put on the protective cap
when the battery is not in
use.
Do not store the battery in
a place where children or
pets could come near it.
Do not drop or apply impact
to the battery.
Do not use a broken or
damaged battery.
Do not charge the battery
in a place where children or
pets could come near it.
Use the charger on a level
surface. After use, do not
keep it plugged into the
power outlet.
WARNING
Protective
cap
7
Protective
cap
53