On Sunday, June 21, 2020 at 11:42:58 AM UTC-4, kinsell wrote:
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.

- not necessarily. Some of the older radios misbehaved when the "12V" SLAs were depleted down to under 12V. So people used 7-cell "14V" SLAs. With the LFP batteries maintaining above 13V through their discharge, I believe those 14V SLAs can be abandoned. Not to mention that very few of those old balky radios are still in service.