A BIG one. It should be rated to deliver at least 2500 watts continuously. Such an inverter would be very costly, and run even a very large battery down very quickly. A generator rated for 2500 watts or more would be much easier, and probably cheaper, to feed.
Vacuum cleaners need power inverters that can handle the start-up and running surge. This is why we really like to get the specs of the unit you hope to use in your mobile application. Here is a sample setup for a 6.5 HP Vacuum Cleaner. Electrical Rating: 120V~60Hz - 11 amps 11 Amps X 120 Volts = 1320 Watt Load I always try to add an extra 30% to any motorized loads. 1320 Watts X 1.3 = 1716 Watts So on this vacuum cleaner I would recommend the following inverters: 1750 Watt Vacuum Cleaner Heavy Duty Inverter 2000 Watt Sine Wave Inverter for Vacuum Cleaner Applications
