TDK Corporation has released the TDK-Lambda brand, EVS series constant current AC-DC power supplies. The board-style, 300 W rated models can operate without forced air cooling, and the enclosed 600 W models have an internal cooling fan. These five-year warranty power supplies are ideal for charging batteries in energy storage systems, or for other applications requiring constant-current outputs such as water purification or plating.

The EVS series will accept a wide 85 to 265 V_AC input and has nominal 18 V (300 W only), 36 V, and 57 V outputs for use with 12 V, 24 V, and 48 V lithium ion, nickel hydride, and lead acid batteries. The float voltage is user adjustable down to the nominal battery voltage, and the charging current can set from 50% to 100% of the rated current. Parallel operation is possible.

The units can operate in ambient temperatures ranging from -20 to 70°C with model-dependent derating. The 300 W supplies measure 3.31” x 1.65” x 7.09” with an optional perforated cover, and the 600 W supplies measure 4.72” x 2.4” x 7.48”. A remote on/off function can also be selected on both power levels.

An external, stand-alone reverse protection module is also available which prevents backflow of current into the power supply from the battery. Rated at 20 A and offering 7 to 60 V_DC, the EVS-RP6020 uses a low-resistance MOSFET to reduce the voltage drop to less than 200 mV. This module is available as a board assembly or with a mounting bracket and measures 1.97” x 1.02” x 3.05” and 2.36” x 1.26” x 3.68”, respectively.

The power supplies have 3 kV_AC input to output, 2 kV_AC input to ground, and 500 V_DC output to ground isolation. All are certified to UL/CSA/IEC/EN 60950-1 and carry the CE mark for the Low Voltage and RoHS2 Directives. The EVS series complies with EN55011/EN55022-B conducted emissions and the IEC 61000-3-2 harmonics and IEC 61000-4 immunity standards.