Power pack for Pi 4

[Ags]

My laptop lasts barely 2 hours out in the cold, so it severely limits imaging time. I did get a Pi 4 running Astroberry a while back, but I had trouble getting it to run the AZ-GTi successfully so gave up on it. Tonight I could have got three of four hours of imaging in (instead of just 90 minutes), so I need to get the Pi working. It just needs to capture the images, I can put up with being deprived of my phone for a night while it runs the AZ-GTi (probably good for me). But... what can I use as a portable power source that can last for 6 hours? Ideally the Pi would be writing the data to a thumb drive.

[vlaiv]

Maybe something like this:

 

[vlaiv]

Just did some research, and maybe someone will find this useful.

Using power bank to power camera cooling in the field.

Problem is that power banks are 5V and we need 12V, right? Well, appears that above power bank and many others that support QC 2.0 (quick charge protocol 2.0) can deliver 12V.

We just need to figure out how much running time we can get from one of these fully charged. In above video we have two important bits of information - 20000mah (that is at internal cell voltage of 3.6V) which equates to 20ah at 3.6V which again equals to 72wh

My camera - ASI1600 uses up to 2A at 12V - which is 24W of power at maximum load.  In above video we saw 80% efficiency at 30W, so that would make it about 57wh at 24w or about 2.4h of operation.

If we don't assume 100% cooling utilization all the time (in colder climate, or not trying to reach maximum deltaT) - we could get 4h out of one charge - but at max load - I'd say top limit is 2h

By the way - in order to power it - one would need special cable

https://m.ubitap.com/12V-USB-to-DC-5-5mm-x-2-1-mm-Quick-Charge-QC-2-0-3-0-Trigger-Cable-p249434148

That one triggers Quick charge protocol and outputs 12V. You can also get step up - but these probably cause some power loss, so get that qc trigger cable - or use trigger module and put your own cable onto it.

https://www.amazon.com/5-Pack-JacobsParts-Adjustable-Voltage-Trigger/dp/B08NFK8BPP?th=1

[Ags]

This might do the trick -2 3 Amp USB ports.

https://www.amazon.nl/Anker-PowerCore-Powerbank-Technologie-Smartphones/dp/B00Z9UY65G/ref=asc_df_B00Z9UY65G/?tag=nlshogostdsp-21&linkCode=df0&hvadid=430640613250&hvpos=&hvnetw=g&hvrand=5697410519504224895&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9065148&hvtargid=pla-563106500803&psc=1

[vlaiv]

As far as RPI4 goes - I did see 3A requirement, but I also saw people powering it with 2A and having no issues.

 

[Ags]

My TalentCell battery might actually work. The Pi runs, and it looks ike there is enough current when the camera is connected to the USB 2 port. I can't however connect to the Pi over VNC when the camera is connected on USB 3. I disabled Bluetooth to save a bit of power, but still couldn't get the camera working on USB 3. Not a problem for DSO imaging. It's still not clear if the TalentCell will still work when it is powering the AZ-GTI too.

Edited December 28, 2021 by Ags

[Ags]

The TalentCell nearly works, but a miss is as good as a mile. It can power the Pi4, ASI485MC and AZ-GTi simultaneously, but the Pi4 is very slow, perhaps it enters a power-saving state when current is low. Also the Pi4 only boots when the camera is plugged into a USB 2.0 port. Testing indoors with everything connected, with several random slews of the AZ-GTi during the test, the Pi4 captured 250 images before capturing ceased. That's a long way short of the 1200 or more captures I was looking for. I will try out a fast charging power bank, although it will mean toting two power banks around. This is a useful review of various powerbanks, forgive the Nederlands:

https://tweakers.net/reviews/9200/powerbanks-dertien-20ah-accus-getest.html

Gives a rundown of maximum current of 13 different power banks on this page:

https://tweakers.net/reviews/9200/6/powerbanks-dertien-20ah-accus-getest-maximale-stroomsterkte.html

[vlaiv]

5 minutes ago, Ags said:

The TalentCell nearly works, but a miss is as good as a mile. It can power the Pi4, ASI485MC and AZ-GTi simultaneously, but the Pi4 is very slow, perhaps it enters a power-saving state when current is low. Also the Pi4 only boots when the camera is plugged into a USB 2.0 port. Testing indoors with everything connected, with several random slews of the AZ-GTi during the test, the Pi4 captured 250 images before capturing ceased. That's a long way short of the 1200 or more captures I was looking for. I will try out a fast charging power bank, although it will mean toting two power banks around. This is a useful review of various powerbanks, forgive the Nederlands:

https://tweakers.net/reviews/9200/powerbanks-dertien-20ah-accus-getest.html

Gives a rundown of maximum current of 13 different power banks on this page:

https://tweakers.net/reviews/9200/6/powerbanks-dertien-20ah-accus-getest-maximale-stroomsterkte.html

It looks like Xiaomi 20000mah is indeed very good power bank. It's not very expensive either, around 50e at our local Mi store.

Just be careful - there are two (or more) models available. One that says 50W (at least on our local site) has 3A for 12V (same as in review)

[AstroKeith]

20 minutes ago, Ags said:

The TalentCell nearly works, but a miss is as good as a mile. It can power the Pi4, ASI485MC and AZ-GTi simultaneously, but the Pi4 is very slow, perhaps it enters a power-saving state when current is low. Also the Pi4 only boots when the camera is plugged into a USB 2.0 port. Testing indoors with everything connected, with several random slews of the AZ-GTi during the test, the Pi4 captured 250 images before capturing ceased. That's a long way short of the 1200 or more captures I was looking for. I will try out a fast charging power bank, although it will mean toting two power banks around. This is a useful review of various powerbanks, forgive the Nederlands:

https://tweakers.net/reviews/9200/powerbanks-dertien-20ah-accus-getest.html

Gives a rundown of maximum current of 13 different power banks on this page:

https://tweakers.net/reviews/9200/6/powerbanks-dertien-20ah-accus-getest-maximale-stroomsterkte.html

The RPi4 doesnt have a power saving mode. Sounds like you have some other issues going on. I have a number of RPi4s running astroberry or similar and all with no problems.

Your VNC issues in particular seems strange. Is this just down to poor wifi range. What ever is in USB 3 shouldn't affect it. Are you trying to power a cooler via the USB3?

What RAM size is your RPi4 and what SD card are you using (brand and type)?

[vlaiv]

1 minute ago, AstroKeith said:

What ever is in USB 3 shouldn't affect it.

I'm not really sure of this.

USB3.0 by specification needs to deliver higher amperage than USB2.0.

Maybe some "power allocation" happens when device is plugged into USB3.0 versus USB2.0 connector and that leaves less power for the rest of the system?

3 minutes ago, AstroKeith said:

The RPi4 doesnt have a power saving mode

It's not power saving mode - but there is something called throttling

https://www.martinrowan.co.uk/2019/09/raspberry-pi-4-cases-temperature-and-cpu-throttling-under-load/

RPI4 will lower CPU speed if it overheats.

Maybe it can lower CPU speed in response to low power detection as well?

[Elp]

I've got a Ravpower RP-PB043 20100mAh and off hand it powers a raspberry pi running astroberry with 1 zwo camera attached for 6-8h+ I found, and mines a few years old. Can't say exact time as I topped up the charge between two consecutive days shooting.

 

[AstroKeith]

6 minutes ago, vlaiv said:

I'm not really sure of this.

USB3.0 by specification needs to deliver higher amperage than USB2.0.

Maybe some "power allocation" happens when device is plugged into USB3.0 versus USB2.0 connector and that leaves less power for the rest of the system?

It's not power saving mode - but there is something called throttling

https://www.martinrowan.co.uk/2019/09/raspberry-pi-4-cases-temperature-and-cpu-throttling-under-load/

RPI4 will lower CPU speed if it overheats.

Maybe it can lower CPU speed in response to low power detection as well?

The Pi doesnt have any USB power management. 

The symptoms the OP describes just point to an issue that isnt directly power related. I have literally built about 50 systems using PI's and the biggest culprit is the SD card. Interestingly ASIAIRs also point to this and the stock card supplied by ZWO is notoriously dodgy.

It may be that the SD card driver in the Pi is rather intolerant, and the OS uses the card heavily. I stick to SanDisk or Samsung Class 10  A1, 32GB and even then find about 5% of cards cause issues.

[Ags]

I am using SanDisk Extreme 64GB.

I understand Pi doesn't have any specific USB power management, but assuming the ports are compliant it will support differnt current on the blue vs black ports? I don't have the issue with USB 3.0 when powering the Pi from the mains adapter.

To be clear, I didn't expect the TalentCell to work, so I am not drawing the conclusion immediately that the SD card is at issue...

Edited January 4, 2022 by Ags

[AstroKeith]

32 minutes ago, Ags said:

I am using SanDisk Extreme 64GB.

I understand Pi doesn't have any specific USB power management, but assuming the ports are compliant it will support differnt current on the blue vs black ports? I don't have the issue with USB 3.0 when powering the Pi from the mains adapter.

To be clear, I didn't expect the TalentCell to work, so I am not drawing the conclusion immediately that the SD card is at issue...

The PI4 can supply up to 1.2A to the USB's, no difference between any ports. Its 1.2 total. But a single connection could pull 1.2A on any of the 4 ports. Strictly speaking that makes the 2 USB3 ports non-compliant as they cant BOTH have the mandated 900mA at the same time.

Did you remember to expand the file system after loading the Astroberry image? What RAM do you have?

The Talentcell will probably be limiting its 5V output to 2.4A at best. At boot, 3A is recommended for the Pi if peripherals are connected.

The four USB ports are all connected to the same 5V supply on the Pi pcb. The USB2 and USB3 have different data busses though. Any difference in boot up may be due to the drivers handling things differently.

The Pi's wifi is notoriously weak, especially if in a metal box or near metal. If weak the error correction kicks in and the VNC gets very laggy as info is resent.

 

[Ags]

13 minutes ago, AstroKeith said:

Did you remember to expand the file system after loading the Astroberry image? What RAM do you have?

Expand file system? I am afraid that's new to me. I didn't  see anything about that in the docs unless I missed something (very likely). Regarding RAM, I  got the biggest one, 4GB or 8GB I think... I will verify tonight.

I do have a SanDisk 32GB card currently holding am image of RetroPie. Would 32GB vs 64GB make any difference?

I am sure the TalentCell is below spec, so the first thing I will do is get a better power pack. And look at expanderising the file system 😀

My Pi has a lovely passive cooling metal case, so I'm sure wifi could be an issue.

Edited January 4, 2022 by Ags

[AstroKeith]

28 minutes ago, Ags said:

Expand file system? I am afraid that's new to me. I didn't  see anything about that in the docs unless I missed something (very likely). Regarding RAM, I  got the biggest one, 4GB or 8GB I think... I will verify tonight.

I do have a SanDisk 32GB card currently holding am image of RetroPie. Would 32GB vs 64GB make any difference?

I am sure the TalentCell is below spec, so the first thing I will do is get a better power pack. And look at expanderising the file system 😀

My Pi has a lovely passive cooling metal case, so I'm sure wifi could be an issue.

Looks like the latest 2.0.4 Astroberry has done away with this requirement. As long as your 64GB card is a good one, no need to re-burn your other 32GB card.

I'd get the Pi working smoothly while hardwired to ethernet. Then try the wifi. If its in a metal case then I think its going to be bad. I've never found the need for metal cases for cooling. 

[Ags]

Running the Pi now, it is clearly a 4GB model.

I am very fond of the metal case. They say don't judge a Pi by its cover, but I must be very shallow...

Given that the onboard wifi is weak, I will get an external wifi with an antenna rather than get rid of the case. Something like this:

https://www.sossolutions.nl/wifi-adapter-met-ap-access-point-mogelijkheid

Edited January 4, 2022 by Ags

[vlaiv]

4 minutes ago, Ags said:

rather than get rid of the case

Oh yea, you need a slim one instead :

[AstroKeith]

Yes, USB Wifi dongles can be fine.