Honda 2005 VTX1800C Owner's Manual page 159

Battery
We recommend using a ''trickle'' charger
( ) for home charging. These units can be 1
left connected for long periods without
risking damage to the battery. However,
do not intentionally leave the charger
connected longer than the time period
recommended in the charger's instructions.
Avoid using an automotive-type battery
charger. An automotive charger can
overheat a motorcycle battery and cause
permanent damage.
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Servicing Your Honda