A system comprising: first and second hearing assistance devices (240, 250, 640, 650) each comprising a rechargeable lithium-ion power source and power management circuitry (644, 654) configured to control charging of the power sources; and a portable charging unit (100, 200, 300, 400, 500, 600, 602, 1000, 1302) comprising: an interface configured to receive a connector of a power cable or a power and data cable; a rechargeable lithium-ion power source coupled to the interface; first and second charge ports (104, 106, 206, 216, 306, 316, 602, 610) configured to receive the first and second hearing assistance devices (240, 250, 640, 650), and charging circuitry coupled to the first and second charge ports (104, 106, 206, 216, 306, 316, 602, 610) and to the rechargeable power source of the charging unit; wherein the power management circuitry (644, 654) and the charging circuitry are configured to cooperate to fully charge the power sources of the hearing assistance devices (240, 250, 640, 650) at a charge rate at or below 1.0C when a state of charge, SoC, of the power sources is outside a predetermined SoC range, and wherein the power management circuitry (644, 654) and the charging circuitry are configured to cooperate to partially charge the power sources of the hearing assistance devices (240, 250, 640, 650) at an accelerated charge rate above 1.0C when the SoC of the power sources is within the predetermined SoC range, and the predetermined SoC range is a range from a fully discharged state to about 45% wherein charging at the accelerated charge rate is terminated in response to reaching a predetermined time limit. first and second hearing assistance devices (240, 250, 640, 650) each comprising a rechargeable lithium-ion power source and power management circuitry (644, 654) configured to control charging of the power sources; and a portable charging unit (100, 200, 300, 400, 500, 600, 602, 1000, 1302) comprising: an interface configured to receive a connector of a power cable or a power and data cable; a rechargeable lithium-ion power source coupled to the interface; first and second charge ports (104, 106, 206, 216, 306, 316, 602, 610) configured to receive the first and second hearing assistance devices (240, 250, 640, 650), and charging circuitry coupled to the first and second charge ports (104, 106, 206, 216, 306, 316, 602, 610) and to the rechargeable power source of the charging unit; an interface configured to receive a connector of a power cable or a power and data cable; a rechargeable lithium-ion power source coupled to the interface; first and second charge ports (104, 106, 206, 216, 306, 316, 602, 610) configured to receive the first and second hearing assistance devices (240, 250, 640, 650), and charging circuitry coupled to the first and second charge ports (104, 106, 206, 216, 306, 316, 602, 610) and to the rechargeable power source of the charging unit; wherein the power management circuitry (644, 654) and the charging circuitry are configured to cooperate to fully charge the power sources of the hearing assistance devices (240, 250, 640, 650) at a charge rate at or below 1.0C when a state of charge, SoC, of the power sources is outside a predetermined SoC range, and wherein the power management circuitry (644, 654) and the charging circuitry are configured to cooperate to partially charge the power sources of the hearing assistance devices (240, 250, 640, 650) at an accelerated charge rate above 1.0C when the SoC of the power sources is within the predetermined SoC range, and the predetermined SoC range is a range from a fully discharged state to about 45% wherein charging at the accelerated charge rate is terminated in response to reaching a predetermined time limit.