H&H HES Series Modular Electronic DC Loads

The HES series from Höcherl & Hackl is a modular platform of electronic loads designed for testing DC power supplies, energy storage systems, and other power electronics. The range covers power levels from 600 to 14,400 watts and offers a wide variety of voltage and current configurations. Models are available from 60 to 1200 V and up to 1350 A. With the zero‑volt option for the 60 V models, the unit can operate from extremely low input voltages, making it particularly suitable for testing fuel cells. All models feature a 4.3‑inch graphical touchscreen for easy operation.

The HES series supports all common load modes: constant current, constant voltage, constant resistance, and constant power. These modes can be combined into CC+CV, CR+CC+CV, CP+CC+CV, and CV+CC. For applications requiring precise control of small currents, Multi Range variants are available with three or four current ranges. For energy‑storage applications, an advanced discharge mode is available, including IU‑a profiles.

Measurement and Analysis Functions

All models include an internal DAQ engine that records voltage and current synchronously with timestamps. Up to 40,000 records are stored in a ring buffer and can be retrieved via USB, LAN, or RS‑232. For slow processes, static data logging is available, writing measurement values directly to USB.

The LIST function enables the creation of complex load profiles with individual ramp and dwell times. For fast square‑wave load transitions, a dedicated square‑wave editor is provided. The modulator function supports sine, square, and triangle modulation on a DC setting, with adjustable frequency and depth. Frequency sweeps can be performed in CC and CV mode.

For characterizing power electronics, functions such as U/I sweeps, MPP tracking, and internal battery resistance measurement are available. The MPP function combines periodic sweeps with continuous tracking of the maximum power point.

Interfaces and Automation

All models come standard with RS‑232, USB, LAN, CAN, and an analog I/O port. GPIB is optional. The analog I/O port supports real‑time control of current, voltage, resistance, and power, as well as analog protection limits and monitor outputs. For applications requiring galvanic isolation, the HES06 option is available.

The HES series supports master‑slave operation with up to five identical units. The master controls the total current and presents combined measurement values through the data interfaces. For synchronization between different H&H devices, SyncroLink technology is available, minimizing jitter between units.