When using a voltage adapter to work outside the US, you may have difficulties charging the battery or the battery may not charge.
HP Notebook PCs - Battery Does Not Charge when Using a Voltage Adapter with the Power Adapter
HP power adapters are created for World Wide voltage and frequency specifictions. HP power adapters do no require any power conversion other than the use of the correct power cord and plug to match the power outlet used at your location. Plugging a power adapter into a power converter may cause the adapter to malfunction.