Battery question

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

Thanks for all the replies ! I was leaning toward a 50K bank but now will re think replacing the SLA.

Originally Posted by SoaringXCellence

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

My last flight I noticed the cooling fan running constantly before I closed the canopy . I believe I have the Pi 3 version . Crew Dog electronics purchase from 2 years ago

On Sat, 20 Jun 2020 21:13:49 -0700, SoaringXCellence wrote:

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.

Don't forget that that's a peak rating, and that most Pis only hit that
value during boot or when working continuously on a compute-intensive
task.

The Pi Zero uses 140mA during boot and 50-70mA when idle, but may not
have the connectivity to run, say, a navigation system which will need a
serial connection to a GPS receiver and, maybe, another to a FLARM.

The model A+ peak consumption is 500Ma peak and typically 180MA but, like
the Zero, may not have the connectivity needed for some applications.

The model B+ uses 600Ma peak and 330mA average, but you're unlikely to
want its Ethernet connection in your glider, but it does have 4 USB
sockets.

Its only the models 3 and 4 that start to use serious amounts of power.

All models can drive touch-sensitive displays that connect via the 40 pin
GPIO header. You can now find these using both multi-colour TFT displays
and eInk display technology with decent display resolution (I have a 4"
TFT display with 480x400 pixels) and, of course, a TFT screen turned up
bright will use quite a lot of amps too. Advantage, eInk.


--
Martin | martin at
Gregorie | gregorie dot org

On 6/21/20 6:56 AM, Martin Gregorie wrote:
On Sat, 20 Jun 2020 21:13:49 -0700, SoaringXCellence wrote:

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.

Don't forget that that's a peak rating, and that most Pis only hit that
value during boot or when working continuously on a compute-intensive
task.

The Pi Zero uses 140mA during boot and 50-70mA when idle, but may not
have the connectivity to run, say, a navigation system which will need a
serial connection to a GPS receiver and, maybe, another to a FLARM.

The model A+ peak consumption is 500Ma peak and typically 180MA but, like
the Zero, may not have the connectivity needed for some applications.

The model B+ uses 600Ma peak and 330mA average, but you're unlikely to
want its Ethernet connection in your glider, but it does have 4 USB
sockets.

Its only the models 3 and 4 that start to use serious amounts of power.

All models can drive touch-sensitive displays that connect via the 40 pin
GPIO header. You can now find these using both multi-colour TFT displays
and eInk display technology with decent display resolution (I have a 4"
TFT display with 480x400 pixels) and, of course, a TFT screen turned up
bright will use quite a lot of amps too. Advantage, eInk.



Since we're talking about a Stratux, it requires two rather high-powered
Software Defined Radios and a GPS to make it work, which adds
considerably to the power drain. You should use a high-current charging
cable to supply power, as short as possible, as you can lose several
tenths of a volt in the cable due to IR drop.

You might look at a uAvionix pingUSB as a better alternative, somewhat
more expensive though.


-Dave

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

Be careful when you evaluate the capacity of "power banks". The AH rating is often misleading, even if it is true. E.g., if it has one 3.7V lithium-ion cell (or several in parallel) then when it converts that up (internally) to 5V the AH would be less, by the factor 3.7/5 (plus some energy loss in the conversion). If the power bank has cells in series, e.g., 2 cells, 7.4V, then the voltage conversion to 5V is downwards, and the AH at 5V should be higher - unless (and likely) they rated it at 5V, or simply added up the AH of the cells in series. But all the (smaller) power banks I've seen just had one cell (or two in parallel). The best way to rate them is in watt-hours not amp-hours, but the sellers prefer to make the rating sound better.

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.

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.

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.

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..

Originally Posted by kinsell

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.

Haha Just ordered a 12v 15 ah Lifpo battery and a 12v to 5 v converter.
The SLA was powering an old radio yes. I would like to keep using the Stratux with Foreflight . It's also nice to have all the airport/weather info with a touch . It also has AHHRS ,I'm not planning on cloud flying but it's there if needed.
I am exploring Flarm purchase . Is there a Power Flarm that will give voice alerts with direction ? Currently I'll get a pretty specific warning "Traffic 12 O clock one mile same altitude " . For the money it provides a lot .