Sunday, August 07, 2005


Ultralife Batteries - U9VL

This is Ultralife's specs for the battery that Thomas sells:Ultralife Batteries - U9VL. Note that the maximum pulse discharge is rated at 400 ma... that is just adequate for the ATS-3, which draws about 420 ma at 7.8v (see AE5X's statistics for a 9v alkaline transistor radio battery).

Weight is good at 33.8 grams. Also note the discharge/capacity curve for 60 ohms (125 ma) shows a decline to 7.0 volts at 80% capacity (960 mah apparently.) Short circuit current is initally 3 amps, but falls to about 1.3 amps and then levels off until minute 3, where the current falls again, presumably when the current limiter kicks in (and that's not reversable.)

Current draw from the ATS3 would be about 110 ma in a QSO. The battery will probably last a bit over 5 hours to 7.0 volts. [How did I get that? Assume 44% key down while transmitting... that's exact for "PARIS", 50 elements, 22 with key down... and say 50% transmit time in a QSO, that's 22% transmitting and 78% receiving time. At 7.5 volts, the ATS3 has an output of 2.05w, drawing 404 ma transmitting and 27 ma receiving.]

On continuous recieve, the battery would last around 42-45 hours.


9 Volt Ultralife Lithium Battery

Thomas Distributing carries the 9 Volt Ultralife Lithium Battery, with a 1200 ma nominal capacity... at 10 ma drain, to 5.4 volts. At 27 ohms, it briefly supplies about 10 volts, drops quickly to about 8.3, and remains above 7.2 for 39 hours (see curve at Thomas site, note 27 ma into 300 ohms is 8.1 volts.)
That's about 1,050 mah.

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