Brand Electronics
BPM 20-1850/CI & BPM 21-1850/CI
Digital Power Meters
with Computer Interface

The Brand Electronics line of Digital Power Meters make it simple to determine how much energy an appliance or light is consuming.  As the diagram below shows, plug the Meter into the wall outlet and then plug the appliance into the meter.  The meter then shows you how much power the appliance is currently consuming and how much total energy the appliance has consumed since the meter was last reset.

Featured in Home Power Magazine's "Things That Work" section.
Download article (pdf)

• Find the Large Electricity Users in a Home. 
  Did you know that a water bed can cost $15 per month to heat?  A portable HEPA air cleaner can also use a similar amount.  The monitor on your computer probably uses twice as much power as the system unit (my monitor uses 90 Watts while the main system unit only uses 45 Watts).   The Digital Power Meter makes it easy to measure the energy use of these appliances and measure the savings from efficiency measures that you may apply to the appliance.
  
• Measure Intermittent Loads. 
  Appliances such as refrigerators, air conditioners, electric heaters, and computer printers cycle on and off periodically or vary their power draw.  Measuring the power at one point in time will not give an accurate picture of the monthly energy use of the appliance.  Because the Digital Power meter is an accumulating meter, it can accurately predict the consumption of these intermittent appliances.  Just leave the power meter connected to the appliance for a representative time period, and the meter will show the total energy consumed, including low and high use periods.
• Help Diagnose Equipment Problems. 
  For example, your computer won't turn on.  The Digital Power meter can tell you whether the power supply is working and how much power it is drawing.  This could save valuable diagnosis time.

FEATURES

Measures the Real Power Consumed by an Appliance.  A common misconception is that power is the product of voltage and current and can be determined by a standard multimeter.  This is only true in a few special cases, such as incandescent light bulbs and appliances where all the power consumed is due to electric heating elements.  For most AC appliances, the current waveform is out of phase with the voltage or the waveform is distorted.  Measuring the real power consumption, which is what the utility company measures and charges for, requires a sophisticated device such as the Digital Power Meter.

Measures Voltage and Current 4,000 times per second for Accurate Power Measurement.  By performing so many measurements in a second, the Digital Power Meter can accurately measure power from unconventional power sources such as battery-powered inverters or generators with non-standard frequency.  Also, appliances that draw complex current waveforms, such as most electronic devices, are accurately measured with the Digital Power Meter..

Model 21-1850/CI:

The key feature of this new meter is the ability to log power usage (the meter still has all of the basic functions of a Model 20-1850 as well). Through an easy to use computer interface the meter can be programmed to log average power use during a user set interval ranging from 1 minute to 2 hours. To use this feature, simply program the meter by using the PC, then connect the meter to the load to be measured - the meter does not need to be connected to the PC. The meter will automatically begin logging average power usage during the set interval. The meter has a built-in battery backed clock/calander so power outages will have no effect on the meter logging. The meter will continue logging until reprogrammed by the user, and will collect up to 8, 121 entries (memory is non-volital, so is unaffected by power outages)! When data collection is complete the data is easily and quickly uploaded to the PC for use. The data is stored in any easy to use ASCII text file format. This data can then be used by any program (such as a spreadsheet) for display or analysis.

Software screen shots:

Specifications

Article: Measuring Power and Energy with the Brand Power Meter

by Windy Dankoff
Brand Electronics Digital Power Meters take the guesswork out of load analysis. They measure the power and energy consumption of any AC appliance, including difficult-to-meter load such as pumps, refrigerators and freezers. The results are displayed on an easy to read 16-character LCD. The meter measures power in watts, energy in kilowatt-hours, and elapsed times in hours. You can also enter energy cost per kilowatt-hour, and it will calculate running cost.

The Brand Digital Power Meter has a heavy grounded cord and plug which you insert into any 115VAC outlet. Plug any load into the back of the meter and analysis begins automatically. Anyone can do this, as easily as plugging in an extension cord.

NOTE: For a 230V load like a water pump, the meter must be adapted for hard wiring by a qualified electrician. The model 4-3700 will handle a pump as large as 2 HP.

Brand Power Meter 4-1850 (115VAC, 1850 watts at 1 watt resolution)
Brand Power Meter 4-3700 (115/230VAC, 3700 watts at 2 watt resolution

The Brand Digital Power Meter is accurate under all conditions, at a very reasonable price. It belongs in every solar-electrician's toolbox and every solar dealer's merchandise shelf. 

Downloadable Documentation

Model 20-1850CI
Model 21-1850CI