A:Answer Thank you for your inquiry. The amount of runtime you will get on the BR1500G depends on the combined power consumption of the items plugged into the unit. To find the total wattage load, it is best to look at the technical specifications or user manuals for your computer, printer, monitor and modem. Monitors and modems usually have a low draw (this can vary depending on the model you have), so the more important task would be to find the wattage of the computer and printer. Once you have the combined wattage load, refer to the runtime graph via the link below to see how much time you will have on the BR1500G. Thank you.
http://www.apc.com/products/runtimegraph/runtime_graph.cfm?base_sku=BR1500G&chartSize=large