The Universal laptop battery (16500 mAh & 16.8 V) on sales for £124.82. Do you need it? The Universal battery Pack is a 20-cell, rechargeable, Li-ion battery designed to work with the all brands of laptop. What is more! This External Universal Laptop Battery works with devices which require a 10V-19V Power supply equipment. Comes with connectors that will replicate the connector you have on your AC Adapter. The battery has a capacity of 155W that will run the laptops for 4-7 hours based on your model and normal power settings.