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Old 06-03-2020, 19:52   #1
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Low Power Icon on My Pi

Iím a new Open CPN and Pi user just starting to install my equipment in the boat. Iíve been playing with it in the house and had everything working pretty well when plugged in the house voltage. Now that I have everything installed in the boat, using one of the recommended power converters, Iím seeing the low power lightning bolt when I power up.

Hereís my stuff:

Rasp Pi 3
Official 7Ē screen
Powered USB HUB
12v to 5v converter (see pic)


I took the output of the 12v to 5v converter and ran it to a splitter with one side going to the PI and the other going to the powered USB hub. The lightning bolt is not on constantly, itís intermittent. Other than the low power icon, everything is working, but I have not had a chance to run it for a long period of time yet.

Any help would be appreciated, thanks.
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Old 07-03-2020, 04:43   #2
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Re: Low Power Icon on My Pi

It all depends on how you have implemented the connections to split the wiring. The Pi is very sensitive to voltage losses due to weak connections or too thin cables. Especially when working in burst mode.

Also, it doesn't make much sense to power the separate hub using the same source. The right thing to do is to use one converter device for the Pi and a second identical converter device for the HUB. Otherwise the supposed advantage is minimal as we would still only have 3 Amps for the whole.

By using two converters you will have 3+3 Amps which does represent a noticeable improvement.
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Old 07-03-2020, 04:59   #3
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Re: Low Power Icon on My Pi

Yep, 3A aint enough. I use a 5A supply for a similar setup with a rPI, USB powered hub and a few RS422 adaptors and it's happy as. Avoid the leads with teeny wires too. They're designed to charge phones.
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Old 07-03-2020, 07:51   #4
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Re: Low Power Icon on My Pi

What others said. Get a better cable too. You canít really power a Pi from a USB hub. It needs a dedicated 3A 5V supply with extra heavy USB wire and keep it as short as possible. Less than 10cm is a good rule of thumb.
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Old 07-03-2020, 09:03   #5
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Re: Low Power Icon on My Pi

Thanks for the quick replies. I will get another power source and redo it. The output of the pictured converter is a micro USB. Any suggestions on how to use bigger wires? Should I cut off the micro connector and solder bigger wire on to it?
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Old 07-03-2020, 10:36   #6
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Re: Low Power Icon on My Pi

The official RPi 2.5A power supplies have the right wire. No, donít cut and solder the wires.
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Old 07-03-2020, 11:56   #7
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Re: Low Power Icon on My Pi

I have used that same 3 Amp adapter for years with an Rpi3 and lately with an Rpi4 -using a Micro-usb to USB-C adapter- without problems. Its micro-usb connector is just right. Don't even think about cutting it to change the wires. You'll probably ruin it.

YOUR problem is that you want to draw too much power from where there isn't that much. Just use another extra adapter to power the USB HUB so you have enough power.

Test it using only the Rpi with the power supply and use it without connecting the hub. If you don't see the power icon anymore you need a second adapter for the hub. If it continues to appear you may need a more powerful 5 to 10 Amp converter to avoid problems. Check it out first.
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Old 07-03-2020, 15:42   #8
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Re: Low Power Icon on My Pi

Thanks again to all for the great info. I have ordered another unit and will redo it.
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Old 07-03-2020, 16:07   #9
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Re: Low Power Icon on My Pi

The bigger units have bare wires on the output. Grab these and wire to it and plug the cables supplied with the Pi and hub into them directly...
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Old 07-03-2020, 18:37   #10
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Re: Low Power Icon on My Pi

Quote:
Originally Posted by Reefmagnet View Post
The bigger units have bare wires on the output. Grab these and wire to it and plug the cables supplied with the Pi and hub into them directly...
I understand my assignment. Thanks for the excellent ideas.
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Old 11-03-2020, 07:57   #11
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Re: Low Power Icon on My Pi

I got a new/different power converter and installed it. Also used the wire terminal to usb adapter suggested by Reefmagnet. Everything is installed and working good now. Here's a pic of the new unit. Thanks again for all the help.
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Old 11-03-2020, 11:26   #12
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Re: Low Power Icon on My Pi

It's exactly the same one I have, and it works great. I'm very happy with it.

Also Your installation looks very well done. Congratulations.
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Old 11-03-2020, 12:21   #13
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Re: Low Power Icon on My Pi

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It's exactly the same one I have, and it works great. I'm very happy with it.

Also Your installation looks very well done. Congratulations.
Thank you pinquino. I still have plenty of other issues to learn about with the Pi, Open CPN and instruments. But it feels good the have the basics installed in the boat. Hope to launch in a month. I also have the pypilot to figure out later.
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