Lapcare Adapter for HP 18.5v 3.5A 65W Yellow Pin A laptop adapter is crucial for the smooth use of the device, as it enables you to charge your laptop batteries with ease. Each brand and model has a specific laptop power adapter that is compatible with it. Thus it is important to know your laptop model well before you purchase a replacement adapter for it. Proper voltage, watts and amperage of your laptop model are some essentials that you need to keep in mind.