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Old June 21st 20, 04:42 PM posted to rec.aviation.soaring
kinsell
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Default Battery question

On 6/21/20 8:18 AM, wrote:
On Sunday, June 21, 2020 at 12:13:51 AM UTC-4, SoaringXCellence wrote:
Another item on your list has a very high current draw: The Stratux is based on a Raspberry Pi and those have more current draw than most of the rest of your panel!

I have a 15000mAh LimeFuel external pack I run with my Stratux (Pi 3 based). It goes too low for effective operation of the Pi in about 4.5 hours. The spec for the Pi says it needs a 2.5 Amp 5-volt power supply.

But I have found that some of the Pi devices have lower current needs, and especially if you are making your own Stratux, you should check out a few different units and pick the one with the lowest power draw.

The Stratux software will run on a Pi 2 or 3. The Pi 4 is definitely over kill and uses the most power of the bunch.

Mike




Talking about watt-hours, a "12V" LFP battery outputs 13.x volts through most of its discharge, thus outputs somewhat more watt-hours than an SLA that yields the same amp-hours. Most of our modern avionics use less current when fed a higher voltage, very unlike ye olde light bulb. I've measured that behavior in my Portable PowerFLARM, for example.


The OP said he was using a 14 volt SLA, which I suppose proves how he
absolutely must use SLA.

Back to the original topic, he said he's thinking of adding Flarm, and
most of those products have ADS-B In. I'd suggest going ahead and add
that, get a decent size screen, and forget the Stratux and iPad.