rosetta power consumption

[ls8pilot]

Just wondered what the average current draw of a Rosetta setup is. I see PAW recommend power supply that will deliver 2Amp at 5V, but assume the average is lower than this. Also I guess you have some inefficiency in the 5V to 12V conversion, so if (for example) the average is 1A at 5V, that is 5W, or 417ma at 12V, assume 80% efficient conversion then that implies around 500ma current draw from a 12V battery supply.

Any real-world measures would be appreciated.

[JCurtis]

I can dog out some readings from the Classic PAW which I suspect will be slightly lower than the Rosetta, given the fan and higher power Pi. From memory I think the average was around 750ma with peaks to 1.5A, it’s a very dynamic load and even depends on how much ADSB traffic is about.

Power conversion between 12 to 5 is dependent on the supply, some are better than others. I can take some real world readings during my supplies, which are quite high in terms of efficiency. Are you just looking for basic power consumption? 

Happy to take some definitive readings if loaned a Rosetta, I have calibrated bench meters available.

[ls8pilot]

Thanks for the information, so looks like rosetta likely to be 1A to 1.5A at 5V if slightly more powerful than "classic" unit ?

From what I read the converters run 80% to 90% efficient, which gives me 500ma to 750ma (in round numbers). This compares to a classic Flarm that runs at 150-200ma (12V) and is a similar load to a PNA (eg Oudie) charging it's battery.

I'm just trying to assess impact on a glider installation, my current setup of equipment draws about 500-600ma total (assuming radio not receiving), so this implies PAW would be a significant additional load. Probably means easiest route to is to make the PAW portable with it's own power-pack.

If anyone has a Rosetta and can do some actual measurements that would be useful, or any experience of running Rosetta (I know they are new) on a power pack. I'd be looking for at least 6 hours and ideally 10.

[JCurtis]

Found some old data, but it gives an idea, I would expect this to be higher on a current unit as the software does more than it did back when I took this data.

My supplies are over 90% efficient, and are factory fitted by a glider manufacturer in Europe.  Depending on what battery you can carry, there are amazingly light 12v batteries with decent capacities out there.

[JCurtis]

This shot covers a few seconds worth of data, but shows the 'spiky' nature of the power draw.

[Paul_Sengupta]

Just for reference, a 20,000mAh portable battery gives about 17 hours operation for a classic.

That's 20,000mAh at 3.7V-ish on a lithium pack with about a 90% up-conversion efficiency to 5V.

[ls8pilot]

Thanks - sounds like a power pack is the way to go. You can upgrade the batteries to LifoPE - but the cost of doing so (including chargers) is about twice the cost of a PAW.

Thanks for all the info.

[rogellis]

Is8pilot.

Some useful info for you, from a current glider Paw installation.

The Rosetta may not be ideal in its current format, as it has no speaker system.

We have a standard 7ah lead-acid battery running the Classic Paw, giving 10 to 12 hours duration.

I have used this DC converter, as it is small and mostly RF screened.  No problems with this unit.
https://www.amazon.co.uk/gp/product/B01KFBF1S4

You will need a mini amplifier and speaker to get audio functions.
https://www.amazon.co.uk/gp/product/B00XJF8GM2

But this gets terrible interference from the PAW, if on the same power supply, so you will need a GLI to stop the buzz.
https://www.amazon.co.uk/gp/product/B01IETQQQK

Which is why you will probably need a bigger box than the Rosetta. 
Or another box to go alongside it.

Rog

[ls8pilot]

Thanks very much for the info, I had naively assumed you could just plug a speaker in and get the audio. Sounds like it needs a bit of work to get a carry-on system that is practical in a confined glider cockpit - I'm following the other threads on this subject with interest...

[Paul_Sengupta]

Maybe use a rechargeable amplified speaker.

[Mig29fuk]

I've used one of these as an iPhone Speaker. iS a hardwire Audio. No Bluetooth.
Has USB Charging and ON/OFF Switch. Quite small
https://www.amazon.co.uk/XAM16-B-Portable-Speaker-Compatible-Smartphones-Black/dp/B00GRKSAGI/ref=sr_1_3?ie=UTF8&qid=1527225454&sr=8-3&keywords=x-mini+speaker
Regards
Gerry

[rogellis]

Is8

That combined amplifier-speaker unit I linked to (the little ‘hamburger’) does have a small internal battery, so if you want to charge it up before every flight you can just plug it into the Rosetta 3.5 mm audio socket - with NO interference.   Sort of simples - but with the hassle of something else to charge up after each flight.

R.

[Paul_Sengupta]

Rog, have you tried running the PAW and amplified speaker from a USB power bank rather than from that 12V battery and DC-DC converter? Just for testing purposes.

By the way, the CPT DC-DC converter was previously known to be noisy on here, and there was another recommendation from the forum:

http://forum.pilotaware.com/index.php/topic,745.msg9675.html#msg9675

Another thread on testing a CPT unit here. Results not good for interference:

http://forum.pilotaware.com/index.php/topic,838.msg10029.html

[rogellis]

Yes - I ran the PAW off my computer and it was still noisy.    And I ran it from three different DC converters (including the recommended one) and it was still noisy.

The give-away that it is the PAW creating the noise (and sending it back down the power cables) is that the noise is perfectly in time with the PAWs flashing lights.  And if you disconnect the amp-speaker from the PAW, and run it off a battery, the noise disappears - so the noise is not due to RF interference. 

I have overcome the noise via a ground-loop isolator on the 3.5mm outlet jack.  The GLI is a PFM-box that works surprisingly well - no noise at all now.

But do beware that if the PAW can send interference back down the power lines, it may be interfering with other components in your aircraft.   It might be nice to have some kind of suppression in the system.  (I tried placing ferrous rings all over my circuitry, but even with eight rings installed I could not get rid of the noise...)


R   

[Admin]

Hi Rog

out of interest, in your testing which of the recommended power supplies did you try ?

- Anker PowerCore
- Anker 12v AUX
- Charge2/Charge4

Its worth noting a computer peripheral USB connector is only rated at 500mA Maximum, which is 4X lower than the recommendation.
I cannot comment on the DC converters because there are a plethora in existence.

Thx
Lee