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Old July 4th 09, 09:16 PM posted to rec.aviation.soaring
Eric Greenwell
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Posts: 1,096
Default Battery life when running a transponder

Hal wrote:


With a becker transponder, 302,303, Dittle radio, and pda 4700 I get
about 3 hours on one 7amp/hour battery. Most of the flight at 14k and
above. When I fly in congested areas altitude is lower but 3 hours
seems to be about all I get there also. Older batteries get less. I
also have a hook-up for PCAS but I was not using it this week (in
shop). The solar option on the glider would be nice as that helps.


Your setup sounds like it would have less than 1 amp draw, which would
give almost 6 hours off a new 7 AH battery. Have you measured the actual
draw? What is the battery voltage at the end of 3 hours?

--
Eric Greenwell - Washington State, USA
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* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org