Elgee - Model 534-B - Battery Powered Industrial Vacuum Cleaners Manual

For use where gasoline and propane engines become a hazard, use of two 12 volt deep cycle type batteries produce a 24 volt system for longer operation time. An optional charger is available. Batteries may be charged on the Power Vac by plugging into the charger, or batteries may be removed to a charging table and a fresh set replaced for continuous use. Depending on batteries, 90 minutes of operation are available. Batteries purchased locally.