Power Experiment

[ryanheathheli]

So I just got an Anker PowerCore 10000mAh pack to power my PilotAware Rosetta

https://www.amazon.co.uk/gp/product/B072MH1434/ref=ppx_yo_dt_b_asin_title_o00__o00_s00?ie=UTF8&psc=1

Obviously I was interested to know how long this would power the device for so, being a programmer by trade, I wrote a little bash script to ping the PilotAware IP every 10 seconds and report when it was no longer available. I though people might be interested in my findings.

First off, reliability.. This was pretty impressive. All in all, the device was unavailable on 8 occasions over the entire test. On all of these occasions it only missed one ping, so I doubt it was actually unavailable (if it had gone down, it would have taken longer than 10 seconds to come back up), so I assume that it just took longer than the permitted 5 seconds to respond on these occasions, or (and I cannot stress this enough), it was some other factor of my test other than the PilotAware!

But, the main event.. how long did it last? Well, from a completely full charge on the 10000mAh battery to completely dying, it was....

10 HOURS, 54 MINUTES and 34 SECONDS!

I'm more than happy with that result, not only will it last for a full day of flying, for my typical use, I most likely won't even need to turn it off between flights, I can just leave it running all day!

I chose the PowerCore 10000 because of it's size, at 6cm wide and 9.2cm tall it matches the size of PAW perfectly so the fact it lasts this long is great. I'd be interested to see if it makes any difference actually using it in the air when it's sending and receiving more transmissions, but I can't imagine it will..

[Ian Melville]

Hi Ryan, I accidentally tested a 22000mAh Power Pack, left it on at the end of the flying day, and it was still running mid-morning the next day!

Personally, I don't discharge batteries below 20% as it shortens the life of the cells.

Cheers
Ian

[grahambaker]

Please don’t leave it running all the time between flights. I find audio warnings from aircraft on the ground a bit of a pain as it is, without extra ones from aircraft that aren’t even running their engines.

[Ian Melville]

Agree with you Graham. FLARM is a big issue in this regard as some glider operations just turn it on during the preflight in the morning and off when they pack up at the end of the day

[ryanheathheli]

Oh yeah, i'll take that point. I was getting annoyed with a glider on the ground when I was testing the other day, I hadn't considered that it would also be transmitting to other PAW users.

Still, that makes my battery life even better

[Ben Smith]

Agree with you Graham. FLARM is a big issue in this regard as some glider operations just turn it on during the preflight in the morning and off when they pack up at the end of the day

This shouldn’t be a problem, proper Flarm units don’t register stationary gliders, where I fly there are often 10-20 gliders in the launch queue all with Flarm on, the only time you normally get an alert from something on the ground is when a tug (with power Flarm) is manoeuvring. Otherwise it could be quite distracting on final approach if you suddenly got alerts from them all.
Also with the club fleet it makes sense to switch the Flarm on before the first launch and leave it on till the end of the flying day, otherwise people would forget to switch it on or hold up the launch queue waiting for it to initialise.

[Ian Melville]

Interesting Ben, I wasn't aware of that.

Lee, is there any merit in doing this in PAW? or at least making it an option.

Cheers
Ian

[grahambaker]

There is less likelihood of PAW users forgetting to switch on their devices before flight as they are likely to be using them as a position source as well as a traffic awareness feed to their moving map displays, and possibly for ADSB-out via their Mode S transponders as well.

[Ian Melville]

Graham, it was PAW ignoring static aircraft that I was referring to, not leaving it on all day.

Though one could argue that FLARM shouldn't transmit until it moves. 

[PaulSS]

If the PAWin an aircraft ignored stationary 'targets' would it still be able to talk to ground stations to get OGN-R, MLAT etc, or would it ignore them because they're not moving?

[Ian Melville]

OGN/R transmits in response to your PAW transmissions. PAW only has to listen, so yes. Filters could be coded to ignore only the aircraft anyway, as you still want it to report ground base objects like obstructions etc?

[rogellis]

Please don’t leave it running all the time between flights. I find audio warnings from aircraft on the ground a bit of a pain as it is, without extra ones from aircraft that aren’t even running their engines.

Good point.

The PAW units in the Long Mynd gliders are left on all the time, as they are difficult to disconnect and time on the ground might only be 1 minute.   So yes, it might be useful to have an option to not transmit on the ground.

One problem with using airspeed (gps groundspeed) as a filter, is that a glider in wave may be flying at zero groundspeed at 6,000 ft (yes this often happens).  So you don't want the PAW to stop transmitting because of zero groundspeed.   

I don't suppose PAW can detect zero height...?


P.S.  Yes, our glider PAWs can do 10 hours on a 12v 8 ah battery  (was yours 12v ?)   But I note that on a summer's day with lots of traffic, that time can come down.  I presume the ADSB aerial is working harder.  It is a shame that that aerial (its pcb) cannot be detuned to filter out long range traffic, as it appears to be the main energy draw.  While it is impressive to see traffic out over the Isle of Man from Shrewsbury, it is not entirely necessary... ;-)


R

[rogellis]

This shouldn’t be a problem, proper Flarm units don’t register stationary gliders.

Not sure this is true of all Flarm units.  Certainly at the Mynd, the gliders on the ground are still chirpinjg, because our PAW units pick them up.   Not sure what grade of Flarm units they are using - probably the cheaper ones.

Not sure how Flarm would get around the same old problem of gliders being stationary in wave.  Why would they risk the Flarm unit switching off, while flying at high altitude?

R

[Ben Smith]

This shouldn’t be a problem, proper Flarm units don’t register stationary gliders.

Not sure this is true of all Flarm units.  Certainly at the Mynd, the gliders on the ground are still chirpinjg, because our PAW units pick them up.   Not sure what grade of Flarm units they are using - probably the cheaper ones.

Not sure how Flarm would get around the same old problem of gliders being stationary in wave.  Why would they risk the Flarm unit switching off, while flying at high altitude?

R

I don’t think that the Flarm units stop transmitting, more that the receiving units are programmed to filter out stationary units (I believe that the full Flarm string includes velocity and heading along with position and height) how this is handled in wave I don’t know.

[Admin]

The problem with filtering stationary objects - which can be done.
What do we do with helicopters ?

I guess we could disable transmit on any stationary type other than helicopters ?

Thx
Lee