RCU Review: RC Electronics Watts Up Meter

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    Contributed by: Greg Covey | Published: January 2005 | Views: 140974 | email icon Email this Article | PDFpdf icon
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    Article by: Greg Covey

    Watt's Up Wattmeter

    The new "Watt's Up" RC battery Watt meter from RC Electronics measures and calculates all the electrical parameters you need to get high performance from your R/C cars or planes. It is an essential tool for increasing the performance and safety of your electric-powered R/C model. With the best balance of specifications and features on the market, you can stop guessing and start knowing "Watt's Up" with your performance!

    Why do I need a watt meter? The "Watt's Up" watt meter helps you:

    * Predict model airplane flight time
    * Ensure peak currents are safe for motor, wiring and connectors
    * Check battery health and whether battery should be retired
    * Evaluate R/C battery charging efficiency
    * Verify that the minimum voltage while operating is within specifications
    * Choose the best propeller or gearing and the most efficient motor
    * Check for wiring and connector power losses
    * Measure power and energy consumption of ANY device with a battery

    Key Features:

    • Measures energy (Wh), charge (Ah), power (W), current (A) and voltage (V)
    • Connector to use a receiver battery for measurement down to 0 V
    • Captures current peaks and voltage minimums(droops)
    • Accurate & precise - 0.01 A current and 0.01 V voltage resolutions
    • Rugged - handles 50 A continuous and 100 A peak at 60 V
    • 14 ga., 7 x 37 stranded, high temp silicone rubber insulated wire without connectors
    • Small & Light: 2.8" long x 1.7" wide x 0.83" thick (70 mm x 44 mm x 21 mm), 2.5 oz.
    • Acts like a wire so doesn't affect model's performance. Precision current sensing resistor, with only 0.001 Ohm resistance and circuitry only draws 0.007 Amps
    • Uses DSP to increase ADC resolution and differential measurement amplifiers to increase noise immunity
    • Factory calibration stores constants in EEPROM to compensate for component tolerances
    • One Year Warranty
    • Complete User Manual


    • Voltage 0-60 V, resolution 0.01 V. That's a 14 cell series li-poly pack!
    • Current 0-100 A peak, 50 A continuous, resolution 0.01 A
    • Charge 0-65 Ah, resolution 0.001 Ah. That's ~32 Amps for two hours!
    • Power 0-6500 W, resolution 0.1 W. That's ~8.7 Horsepower!
    • Energy 0-6500 Wh, resolution 0.1 Wh. That's lifting a 50 pound model into outer
      space (65 mi.)!
    • Operates from 4.0-60 V, 0 V with optional receiver battery pack
      16 x 2 STN LCD display
    • Powerful, 8 MIPS micro-controller

    The "Watt's Up" watt meter comes with a manual but without connectors. I soldered a set of Dean's Ultra connectors onto my meter for testing in a variety of applications.

    The "Watt's Up" watt meter (bottom) goes beyond the specifications of my original Astro Flight meter (top)

    I've been using other watt meters for years like the popular Astro Flight "Super" and "Micro" whattmeters. The single "Watt's Up" watt meter can not only perform the range of both Astro Flight meters but can even go beyond it for specifications not before seen in any other unit.

    Since the "Watt's Up" watt meter can use an external receiver battery, it can measure a voltage range from 0-60v with a 0.01 volt resolution and a current range from 0-100amps with a 0.01 amp resolution. Now, even single-cell Lithium setups can be measured for micro-flight applications.

    Sample measurements I took on a power system that draws around 15amps

    The first screen of my sample measurements (left) shows that the alternating LCD display can capture current peaks and voltage minimums (or droops). It also measures energy used (Wh) and power in watts (W).

    The second and third screens show the same display alternate at different times. The charge level (Ah), power (W), current (A) and voltage (V) are all shown. Only the power in the lower right corner keeps the same units.

    The "Watt's Up" watt meter has been optimized for the needs of the R/Cer with added features like charge display in Ah and power in Wh. Conventional equipment like a DVM often has insufficient current range and too much insertion loss due to internal resistance or long leads.

    My next test of the "Watt's Up" watt meter was to verify the voltage measurement against a Fluke 79 series multimeter
    I measured 0.01v difference which was probably correct since my Fluke meter was tapped at the output connector side after about a 6" wire length at 14amps

    The current peak and voltage minimum capture features allows
    for hands-free measurements

    It can be very difficult to hold the watt meter while holding the plane and transmitter. On larger planes, the prop wash blows the watt meter so you can't see it sometimes. The "Watt's Up" ability to capture even brief current peaks and voltage minimum values can help. The Peak Amps value and Voltage Minimum values will be the peak and minimum captured following the "Watt's Up" power on sequence. Be careful in adjusting test setups to not accidentally cause a current peak or voltage minimum that isn't the one you are watching for. This might happen if, for example, you connect another component to the system while it is measuring. When you throttle back down, your peak current reading and lowest voltage reading will be maintained until you disconnect the flight pack.

    The Peak Amps and Voltage Minimum values are cleared whenever the "Watt's Up" watt meter turns on (i.e. is powered up). So remove all power sources when you need to clear them for a new measurement.

    The watt meter can also be used to measure the charge going into a flight pack

    Another application that comes in handy is to measure the charge going into a flight pack for the lower-end chargers. You can monitor the charge that you put back into the pack and keep a closer eye on the actual current being applied to the pack. I love the inexpensive Apache 2500 chargers for 1-4 cell Lithium packs but often want to measure just how much I depleted the pack after a flight. The "Watts Up" watt meter allows me to do it if I reverse the connector sex by using adapters. Shown above is an already charged 2-cell Kokam 1500mAh pack that I am just peaking up to 8.4v.

    The "Watt's Up" watt meter documented my baseline measurement for a power system upgrade

    When I measured the power on my new ProJeti wing power upgrade with the "Watt's Up" watt meter, it confirmed my suspicion with an eyebrow raising 43amps and 440watts! The finished wing not only balanced perfectly with the new 3-cell Kokam 3.2AH pack but the Lithium pack held a higher voltage at 43amps than any other pack I own.

    The flight test should be fun and I'll have a documented reading to refer back on.


    When racing cars or flying electric planes, there are times when you need to verify the performance of your power system. The "Watt's Up" watt meter can be used to keep your power system in top condition by measuring critical parameters under load or battery pack capacity. The values measured by the watt meter can then be compared to manufacturer's specifications or your own baseline measurements.

    There have been times when I have suspected poor motor performance, when in fact, a watt meter has proven the issue to be poor battery performance. Fine-tuning your R/C electric model for great performance doesn't have to be a guessing game. The watt meter easily showed me that the battery I was using could not deliver the current needed for my motor. Without a tool like the "Watt's Up" watt meter, I would still be guessing about which component of my power system to change.

    RC Electronics
    2980 East Capitol Expy. #50-194
    San Jose, CA 95148
    (408) 705-1980

    Comments on RCU Review: RC Electronics Watts Up Meter

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    The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.

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