Measuring Standby Power
Where to Obtain Meters
Companies that currently sell Watt meters suitable for the recommended test methods:
- Electronic Product Design, Inc.
- Hioki USA
- Hioki, Japanese site
- Voltech Instruments, Inc.
- Yokogawa Corporation of America
FEMP encourages other manufacturers of suitable meers to submit their information.
Unofficial Summary of IEC 62301
A method for testing standby power use in appliances is described in this test procedure. A summary of the key points is given below to introduce you to the general approach. However, you should consult the official document (available at webstore.iec.ch) before undertaking the test.
Scope
The test applies to all devices that are plugged into the electric mains by the end user. The test is designed to measure the energy consumption of devices while in their standby mode and other low-power modes.
Terminology
The standby power consumption is defined as the lowest power consumption while plugged into the mains power supply. Other defined terms include standby mode, rated power, voltage and frequency.
Testing Conditions
IEC 62301 defines testing conditions. The ambient temperature should be 23 (+/- 5) degrees C, with still air. The harmonic content of the supplied power shall not exceed 2% up to and including the 13th harmonic and the ratio of peak value to r.m.s. value of the test voltage (sometimes called the crest factor) shall be between 1.34 and 1.49
The accuracy of the measuring equipment is also defined but depends on the amount of power being measured. Measurements above 0.5 W must be made with an uncertainty of less than to 2% at the 95% confidence level.
Firms That Measure Standby Power
Test labs which currently provide standby power measurment:
- Electronic Product Design, Inc., phone: (541)741-0778
- Wyle Laboratories, Inc. Contact: Davin Lee, Laboratory Manager, (256)837-4411 x494, or Joe Hazeltine, PE, (256)837-4411 x390
- Ecos, Contact: Craig Billingsley, (970)259-6801 x314
FEMP encourages independent testing labs who provide Standby Measuring services to submit their information.
The power measurement instrument must be able to resolve:
- 0.01 W or less for power measurements below 10 W
- 0.1 W or less for power measurements above 10 W (up to 100 W)
Portable Appliances
IEC 62301 defines a "portable" appliance (that is, is intended to operate on rechargeable batteries when not connected to a power source.) For portable devices, the standby mode is measured on the charger or docking/base station with the appliance detached.
Measurement Procedure
If power consumption is stable (defined as less than 5% variation from the mean over an interval of 5 minutes), then the power consumption can be read directly from the meter; if power consumption fluctuates, then energy consumption should be measured over a period of time and then divided by the measurement period to determine average power.
IEC 62301 also lists information to be reported when making a measurement.