Johntammi, if your 12 volt battery is down to 11 volts, it may be ruined. A fully charged 12 volt lead/acid or gell cell should read 13.5 volts or slightly higher. It should never be discharged below 11.9 volts or you risk permanent damage to it. If it is now reading 11 volts, chances are, as soon as you put a load on it like your starter, the voltage will fall to a much lower value. You may be able to charge it up again, worth a try before junking it, but even then it may fall far short of advertised ampere-hours now. A battery tender or battery minder (different names for a device that will keep your lead/acid batterys charged without damaging them is a good investment. Just Google "battery tender" to find some sources.