On Sunday, June 21, 2020 at 8:48:18 AM UTC-7, wrote:
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.

They better not be in service because they are illegal to use and have been illegal for many year..