SSD Booting : low power issue

[HeviiSailor]

I'm able to succesfully boot my Rpi4 from an external SSD connected directly via USB3 cable. Works like a proverbial charm! Until, that is, intensive work is being done. At that point, the dreaded "low power" warning rears its ugly head just before the Pi hangs .

I understand the limitations of available current from the Pi itself. This is why I subsequently connected the SSD to the powered USB hub instead. However, it's clear that the hub isn't recognised until after booting since the Pi now boots from the original SD card (still installed).

Any suggestions on how this issue can be resolved ?

[Boatingbaileys]

Hi, this still sounds like a low power issue. Have you been able to measure the voltage on the Pi GPIO pins or with a USB voltage tester? You might find that during these periods it's dipping just a little too low. I had a similar issue myself and ended up using adjustable power suppliers on the boat which I kept adjusting until this went away.

[HeviiSailor]

...ended up using adjustable power suppliers on the boat which I kept adjusting until this went away.

Interesting: Can you describe the actual components? At this point I don't have an adjustable power supply. I'm currently powering the Pi from a (12V in, 5V out) powered USB hub. I also have a 12V-5V buck converter which I've never connected as I hadn't had problems with the existing configuration. I suppose that the first thing to do is try to power the Pi directly from the buck.

As I'd like to maintain the convenience of being able to physically disconnect the Pi, I'll cut off one end of a micro USB cable and then splice onto the buck's 5V output. Does this seem to be a reasonable approach?

If I'm still faced with the low power issue after having gone through the above, is there any way of powering the SSD (SATA Connection) separately from the Pi?

[baltika_no_9]

I wonder if this is a manifestation of the well known back powering issue? I am not sure but maybe worth looking into.

The cause is that the hub is trying to power the pi yet the pi is of course providing its own power.

You can search for compliant USB hubs where the back powering is disabled. This may be useful as an example.

https://www.addictedtotech.net/best-powe...4-in-2021/

EDIT - Having re-read your post are you saying the pi and the SSD are powered from the same hub?

[HeviiSailor]

Having re-read your post are you saying the pi and the SSD are powered from the same hub?

Yes, at this point they are. Hence I intend to power the Pi from the 12-5V buck. I'd like to still connect to the pi via the micro USB port.

Although I'll do a deep Google dive to try to find a pin-out, does anybody have such a diagram handy? I'd hate to connect thw wrong leads and fry my board!

  * "Baltika 9". Mmmmm..., one of my favourite beers .

[baltika_no_9]

Any good? https://www.neverstopbuilding.com/blog/w...usb-pinout

 One my favourite beers too but hard to get in the UK.

[HeviiSailor]

Any good? https://www.neverstopbuilding.com/blog/w...usb-pinout.

Thanks for the link. It's a good one. 

I also discovered that I can get a buck ($12) with the appropriate USB whip. If I can't find a USB C cable to cut apart, I just may go this route.


*Armenia was awash in Balika 5, 7 and 9 a few years ago.
**Unibrou in Canada brew a couple of similar style beers. If you can get your hands on them, you might also enjoy Fin du Mond and Trois Pistoles

[Boatingbaileys]

...ended up using adjustable power suppliers on the boat which I kept adjusting until this went away.

Interesting: Can you describe the actual components? At this point I don't have an adjustable power supply. I'm currently powering the Pi from a (12V in, 5V out) powered USB hub. I also have a 12V-5V buck converter which I've never connected as I hadn't had problems with the existing configuration. I suppose that the first thing to do is try to power the Pi directly from the buck.

As I'd like to maintain the convenience of being able to physically disconnect the Pi, I'll cut off one end of a micro USB cable and then splice onto the buck's 5V output. Does this seem to be a reasonable approach?

If I'm still faced with the low power issue after having gone through the above, is there any way of powering the SSD (SATA Connection) separately from the Pi?

I’m running something like these

https://amzn.eu/d/cNIZSCE

And I tested the usb voltage with a unit like this (cheaper on eBay). 

https://amzn.eu/d/5KqSL6c

[url=https://amzn.eu/d/5KqSL6c][/url]I think the official Pi power supply is 5.1v and a lot of these usb power supplies drop when any serious load is supplied. I had to change mine from a plug and play unit to the above and then fine tune the voltage to get rid of any issues. It’s probably set at the device about 5.2 volts to allow for any voltage drop in the cables. I’m running an SSD setup too.

[HeviiSailor]

I’m running something like these...

Thanks for this information. It seems that these adjustable bucks are a much better option than the non-variable unit which I currently have:

Is the output of yours constant if the input varies? This is actually rhetorical since I'll be ordering a handful, regardless. A bonus to this is that now I'll be one step closer to emulating your impressive engine sensors as well!

[Techstyle]

I’m running something like these...

Thanks for this information. It seems that these adjustable bucks are a much better option than the non-variable unit which I currently have:

Is the output of yours constant if the input varies? This is actually rhetorical since I'll be ordering a handful, regardless. A bonus to this is that now I'll be one step closer to emulating your impressive engine sensors as well!

I am using this one, its adjustable:  https://amzn.to/3rvaHif
and I have it connected straight to the 5v and ground pins on the GPIO.  some people say this is not the best practice, as it may bypass some protection but I have had no issues in 2 years, plus I have a 3amp fuse inline with it.  however, you may be better splicing it like you are planning.

All my other peripherals are connected to a 12v usb hub which gets battery voltage - https://amzn.to/32YXCUG, I have 2 of these 

my schematic is attached 

I am also working on an engine sensing project like Boatingbaileys...