For only a month? Fill up the gas tank, and put a "battery tender" on the battery. It's a trickle charge adapter that you plug in the wall and hook to the battery to keep it fresh while it sits...http://batterytender.com/products/automotive/battery-tender-junior- 12v-at-0-75a.html
If you don't have access to electric for a battery tender, as Tom said, simply disconnect the negative (-) battery cable. That way the battery won't run down while in storage. HTH. -Jim
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