US Patent 10483781 Electrically heated aerosol-generating system

A method of controlling an electrical system is provided, the electrical system including a primary charging device including a first rechargeable power supply, and a portable device including a second rechargeable power supply, the method including monitoring an ambient temperature adjacent the primary charging device, determining a charging current for charging the first rechargeable power supply of the primary charging device, in dependence on the ambient temperature, and charging the first rechargeable power supply of the primary charging device at the determined charging current. There is also provided a system and device for performing the method.