Flying High with West Mountain Radio's CBA IV

Fred Schwierske

Article from the West Mountain Radio Quarter 4, 2015 Newsletter


For years, conventional model airplanes used nitro-methane fueled two-cycle engines. Although capable of high power output in small size packages, these "gas" models could be finicky to operate, annoyingly loud, and sprayed a trail of messy oil residue in their wake.

Remote Control (R/C) model aviation entered a new era with the availability of modest cost, high capacity lithium polymer (Li-Po) batteries. Lithium technology offered ease of use, high energy density, long life, and clean operation. Over the years, model airplane electric motors have continued to grow in capacity, requiring ever more powerful battery packs. Hobbyists participating at the "high end" of the sport continually seek maximum performance, and ever larger model sizes - which typically cost from a few hundred to many thousands of dollars. Although gas powered models are still popular, electric powered model airplanes now represent an important and growing segment of the total model airplane market.

Battery packs to power these models are available in a wide variety of sizes. Common pack voltages range from 11.1 to 18.5 volts. Capacities of 2000 to 5000mAh provide for 7 to 10 minute flight times. Even more impressive, when needed, packs are capable of short term discharge rates in excess of 100 Amperes!

Obviously, the cost of a model airplane and its internal electronics, combined with several hundred foot altitudes and impressively high speeds, leaves little tolerance for substandard battery packs.

Enter West Mountain Radio's Computerized Battery Analyzer (CBA IV).

As background, the CBA has long been used by R/C car hobbyists, who historically used conventional NiCad and NiMH based battery packs. However, testing high capacity Lithium Polymer packs required considerable time using the CBA's 100 watt discharge capacity.

Recently, Greg Gimlick - noted columnist and expert on electric model aviation wrote several columns in leading industry magazines using West Mountain Radio's CBA IV and companion 500 Watt Amplifier. He noted that while not for all hobbyists, the 500 Watt Amplifier allowed expanded testing at real world current levels not otherwise available. Evaluating a battery pack at a 20 amp discharge level may reveal serious operational weakness that is not apparent when testing at lower currents.

If you are interested in reading more about LiPo battery pack testing with the CBA and 500 watt amplifier, check out the following articles (Model Airplane News may be accessed on-line):

Model Aviation Magazine (AMA)
Aug 15, 2015 issue
Product Spotlight Column - pages 16 & 17.
(Must have subscriber account to access AMA archives.)
http://www.modelaviationdigital.com/modelaviation/august_2015?pg=1#pg1

Model Airplane News
Sept 2015 p76-79 "Mount 'em Up!"
Ultimate Electrics Column, by Greg Gimlick
See page 79 article: Product Highlight - "Computerized Battery Analyzer".
Includes photo of CBA, Amplifier, Cables, Crimper, and CBA Graph.
http://www.modelairplanenews-digital.com/man/september_2015?pg=78#pg78

Model Airplane News
Nov 2015 p62-65 "LiPo - Charging Basics"
Ultimate Electrics Column, by John Kauk
See page 65 article: "Next Level Battery Management"
Includes photo of computer, CBA, Amplifier, battery, and multi-overlay test graph.
http://www.modelairplanenews-digital.com/man/november_2015?pg=64#pg64

In summary, model aviation hobbyists can now evaluate high performance battery packs to:
* Compare performance of similar capacity batteries from different manufacturers.
* Confirm a battery's actual performance versus published specifications.
* Measure base line performance of a new battery, then re-check capacity as it ages.
* Evaluate varying load conditions on actual battery capacity.
* Determine effect of various ambient temperatures on actual battery capacity.

For complete details on West Mountain Radio's Computerized Battery Analyzer product family, see:
http://www.westmountainradio.com/cba.php