Honda TRX500FM Owner's Manual page 172

Battery Storage
Refer to Saf ety Precautions
If you plan to store your ATV, we recommend you remove the battery
and store it where it can be charged at least every 30 days to maintain its
service life.
If you do not remove the battery, we recommend disconnecting the
battery cables (negative cable first).
You will get the best storage results from removing the battery and slow
(trickle) charging it every 30 days (see
Before you remove the battery, be sure to read all the information that
follows, as well as the information on the battery label.
The battery gives off explosive hydrogen gas
during normal operation.
A spark or flame can cause the battery to
explode with enough force to kill or seriously
hurt you.
Wear protective clothing and a face shield, or
have a skilled mechanic do the battery
maintenance.
on page 95 .
Battery Charging,
Servicing Your Honda
Battery
page 166 ).
163