Not so, if it's at 36V static (Not being used) it needs to be charged.
Lead acid battery discharge is not a linear function, from nominal battery voltage (i.e. 36 volts) to zero. To put battery voltage versus charge state in perspective - a healthy, fully charged 12 volt lead acid battery will be 12.7 to 12.8 volts (high performance batteries even higher). At 11.9 volts, a 12 volt battery is effectively discharged. You can pull them lower than this (not much useable power), or if not charged they will continue to drop voltage, but this is where damage occurs. An 80% discharged battery (12 volt) measures about 12.0 volts. Multiply these numbers by 2, 3, or 4 for 24, 36 or 48 volt forklift batteries.