Kevin Hardy, Senior Development Engineer
Scripps: Institute for Geophysics and Planetary Physics, Marine Biology Research Division
Turn your laptop into an advanced battery tester for between $150-$300. You can then easily determine what effect current drain, temperature, or pressure will have on the capacity of your system battery. The CBAIII Pro from West Mountain Radio will be demonstrated. Set-up is easy with a USB cable to the PC, software CD, and battery leads.
Unlike a simple resistive load tester, where current will change with decreasing voltage, the CBA will perform a constant current test on virtually any type or size of battery, any chemistry, with any number of cells up to 55 volts, recording data continuously to your PC. Your results of single battery, or series and parallel stacks may be surprising. The CBAIII has a few quirks, but all and all it's quite useful.
The CBA is capable of test rates of up to 40 amps or 150 watts, whichever is higher. Versions to handle up to 2000 watts are possible. It graphically charts voltage versus amp-hours until a pre-determined cut-off voltage is reached, where you see total amp-hr capacity.
Graphs may be displayed, saved and printed. Multiple graphs of the same battery, or multiple batteries, may be overlaid for comparison. Battery tests may be printed on a color or black & white printer, or saved as a pdf and e-mailed. Test results can be printed on Avery 5160 labels to be affixed to individual batteries to log their test date and performance.
More info on the CBA III is at:
http://www.westmountainradio.com/content.php?page=cba
Bonus presentation: Deep water plastic spheres
In any time remaining, moderate-cost injection molded trawl floats will be shown which have the potential for use as instrument housings to 1,400m. Injected molded hemispheres of styrene plastic are thermally fused into a hollow sphere. Some interesting opportunities exist. ABS (Acrylonitrile butadiene styrene) and styrene plastic maybe solvent welded to create ports. All plastic model building techniques apply. Samples will be shown. If anyone is willing to try this, see the speaker afterwards. We'd ask the experimenter to share their results, good or bad, at a later STF meeting.