The AKG CU4000 charging system for the WMS4000 wireless series consists of the CU4000 charging unit and two BP4000 battery packs. The charging unit itself is a stand-alone unit in a rugged plastic housing, featuring 2 charging compartments, each designed to hold either one HT4000 handheld transmitter, a PT4000 bodypack transmitter or a BP 4000 spare battery pack. Two battery packs can be charged simultaneously by the CU4000, and there is no need to remove the battery packs since the transmitters are equipped with on-board charging contacts for a plug-in charge. Safety switch-off occurs by detection of the peak voltage, the negative voltage slope or a predetermined time out. Thus the battery pack is prevented from overcharging. An integrated two-slot power management system allows the charging unit to charge two battery packs simultaneously in approximately 1 hour.

Since the BP4000 battery pack incorporates microprocessor-controlled surveillance intelligence, there is a permanent data stream between the charging unit and the battery pack to protect the batteries from any damage caused by the charging process. The charge balance management also features a self-discharging counter used to detect the exact battery pack status after a long period of storage. With the help of this charge balance management, an accurate remaining battery life display can be realized on the transmitters (transferred via pilot tone to the SR4000 receiver).

The battery pack also features an internal temperature surveillance circuit that adjusts the charging current of the CU4000 to protect the device in case of low or high temperature during loading. To reduce the so-called memory effect which leads to decreasing battery capacity, the communication between the BP4000 and the CU4000 is able to calculate if the batteries need a recovery cycle by the help of the stored date in the BP4000. The recovery cycle refreshes the battery pack by charging and discharging cycles to determine the actual capacity and initialize the capacity counter for accurate use time calculation. Other controls include a 3-step LED display showing the charging status. Due to the sophisticated charging system, the battery pack can power the HT4000 and PT4000 for up to 12 hours with one full charging cycle, plus its gentle charging function will ensure up to 1,000 cycles.

• Intelligent battery supply system with CU4000 charger and two BP4000 battery packs
• Microprocessor-controlled charge/discharge monitoring function
• One-hour quick charging and Battery Recovery Management
• Battery pack can be charged inside the transmitter
• Includes power supply