A method of controlling an electrically heated aerosol-generating system is provided, the system including a charging device including a first rechargeable power supply, and an electrically heated aerosol-generating device configured to receive an aerosol-generating substrate and including a second rechargeable power supply, and at least one electrical heating element; and the method including monitoring an ambient temperature adjacent the charging device, determining a charging current, for charging the rechargeable power supply of the charging device, in dependence on the ambient temperature, and charging the rechargeable power supply of the charging device at the determined charging current. There is also provided a system and device for performing the method.