Thebuttsniper
Posts: 5
Joined: Thu Jul 04, 2019 12:25 pm
Location: Oregon

Y usb cable for power?

Thu Jul 04, 2019 12:42 pm

I am totally new to pis and all this fancy stuff, That being said I am typing on it currently! Although sometimes while doing certain task I get a lightning bolt in the upper right hand corner! I bought a multi usb charger that is rated at 5v 2.4a (https://www.amazon.com/gp/product/B018Q ... UTF8&psc=1) I was wonder if it was would safe and or practical to use an external HDD power cord such as (https://www.amazon.com/gp/product/B0047 ... UTF8&psc=1) to power and if it would help get rid of the lightning bolt problem. So far the only time I get the bolt is during internet browsing.

Thanks for reading that mess.

epoch1970
Posts: 3538
Joined: Thu May 05, 2016 9:33 am
Location: Paris, France

Re: Y usb cable for power?

Thu Jul 04, 2019 6:16 pm

Doesn't sound like the best idea
https://electronics.stackexchange.com/q ... -usb-cable

Especially when said cable is half the price of the official PSU for Pi. Which performs well and comes with a long, non-detachable cable (a good thing indeed).
"S'il n'y a pas de solution, c'est qu'il n'y a pas de problème." Les Shadoks, J. Rouxel

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jbeale
Posts: 3474
Joined: Tue Nov 22, 2011 11:51 pm
Contact: Website

Re: Y usb cable for power?

Thu Jul 04, 2019 6:53 pm

When the lightning bolt appears sometimes (meaning low voltage detected on the Pi) it means either a cheap USB cable with too high resistance (smaller wires with less copper are cheaper) or a not-good-enough power supply. Not all power supplies deliver what the label says they should, especially less expensive types. Power supplies can also work OK at first but then get worse over time, especially the cheaper kinds. These cheap USB supplies can still work OK for charging phones (just more slowly) which is why people get away with selling them, but not so good for the Pi.

Get a good quality power supply including heavy duty cable, and this will not happen.

Thebuttsniper
Posts: 5
Joined: Thu Jul 04, 2019 12:25 pm
Location: Oregon

Re: Y usb cable for power?

Thu Jul 04, 2019 10:56 pm

My setup prevents me from using the standard power supply. I 3d printed a retro computer https://www.thingiverse.com/thing:3478048 I am limited in room inside this thing and I wanted to limit the amount of cables coming from the back of this thing. maybe I could find an alternative powering thing about the same size as this? is there a certain spec I should be looking for? from what I understand amps is what controls the speed of which the phones are charged/power is delivered. I guess I could go back to the board.

Would this cable damage the pi? double the amps is what I am really worried about. Are there also alternative to the micro usb plug?

W. H. Heydt
Posts: 10741
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: Y usb cable for power?

Fri Jul 05, 2019 1:25 am

Thebuttsniper wrote:
Thu Jul 04, 2019 12:42 pm
I am totally new to pis and all this fancy stuff, That being said I am typing on it currently! Although sometimes while doing certain task I get a lightning bolt in the upper right hand corner! I bought a multi usb charger that is rated at 5v 2.4a (https://www.amazon.com/gp/product/B018Q ... UTF8&psc=1) I was wonder if it was would safe and or practical to use an external HDD power cord such as (https://www.amazon.com/gp/product/B0047 ... UTF8&psc=1) to power and if it would help get rid of the lightning bolt problem. So far the only time I get the bolt is during internet browsing.

Thanks for reading that mess.
First things first. What model of Pi are you using? The Pi3B and Pi3B+ can use up to 2.5A, though 2.4A should be sufficient for *most* setups. The new Pi4B can use up to 3A and 2.4A *might* be enough. That said, repeat after me "a charger is not a power supply unit (PSU)". Most things being charged can tolerate having the voltage drop as low a 4.2v. A Pi can't. A Pi will give a low voltage warning (that lightning bolt) when the voltage dips to 4.65v.

So...either your "charger" can't deliver the rated current *and* 5v at the same time (pretty likely for a charger), or the voltage drop in the USB cable is enough that, under a reasonable load, that causes the low voltage indication.

The real solution: get an official RPF PSU for the Pi you're using. It *will* deliver rated current and maintain proper voltage, and the built in cable has thick enough wires (18 ga.) to minimize voltage drop from the cable.

Thebuttsniper
Posts: 5
Joined: Thu Jul 04, 2019 12:25 pm
Location: Oregon

Re: Y usb cable for power?

Fri Jul 05, 2019 2:03 am

W. H. Heydt wrote:
Fri Jul 05, 2019 1:25 am
Thebuttsniper wrote:
Thu Jul 04, 2019 12:42 pm
I am totally new to pis and all this fancy stuff, That being said I am typing on it currently! Although sometimes while doing certain task I get a lightning bolt in the upper right hand corner! I bought a multi usb charger that is rated at 5v 2.4a (https://www.amazon.com/gp/product/B018Q ... UTF8&psc=1) I was wonder if it was would safe and or practical to use an external HDD power cord such as (https://www.amazon.com/gp/product/B0047 ... UTF8&psc=1) to power and if it would help get rid of the lightning bolt problem. So far the only time I get the bolt is during internet browsing.

Thanks for reading that mess.
First things first. What model of Pi are you using? The Pi3B and Pi3B+ can use up to 2.5A, though 2.4A should be sufficient for *most* setups. The new Pi4B can use up to 3A and 2.4A *might* be enough. That said, repeat after me "a charger is not a power supply unit (PSU)". Most things being charged can tolerate having the voltage drop as low a 4.2v. A Pi can't. A Pi will give a low voltage warning (that lightning bolt) when the voltage dips to 4.65v.

So...either your "charger" can't deliver the rated current *and* 5v at the same time (pretty likely for a charger), or the voltage drop in the USB cable is enough that, under a reasonable load, that causes the low voltage indication.

The real solution: get an official RPF PSU for the Pi you're using. It *will* deliver rated current and maintain proper voltage, and the built in cable has thick enough wires (18 ga.) to minimize voltage drop from the cable.
Repeat after me; being condescending isn't a proper way to relay a point. anyways, dud who posted about crappy cables was correct, it wasn't the POWERSUPPLY/charger I bought.it was the really poorly made after market cable with a power switch that goes to the PSU/charger from the wall. problem solved! thank you!

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davidcoton
Posts: 4007
Joined: Mon Sep 01, 2014 2:37 pm
Location: Cambridge, UK

Re: Y usb cable for power?

Fri Jul 05, 2019 9:02 pm

Thebuttsniper wrote:
Fri Jul 05, 2019 2:03 am
Repeat after me; being condescending isn't a proper way to relay a point. anyways, dud who posted about crappy cables was correct, it wasn't the POWERSUPPLY/charger I bought.it was the really poorly made after market cable with a power switch that goes to the PSU/charger from the wall. problem solved! thank you!
In @W. H. Heydt's defence, a little humour should not be confused with condescension. His reply stems from answering dozens of posts where the issue was about chargers that coannot supply the rated current while maintaining the rated voltage.

I would be really surprised if the real cause of your problem was a cable on the mains side. The current there is much lower, and voltage losses are less significant anyway. It would have to be faulty or of completely incompetent design to cause the charger output to drop significantly. In which case the proper place for it is the WEEE recycling bin -- preferably cut in pieces first.
Signature retired

PhatFil
Posts: 1341
Joined: Thu Apr 13, 2017 3:55 pm
Location: Oxford UK

Re: Y usb cable for power?

Fri Jul 05, 2019 9:39 pm

Nice Pi Case btw..
A post detailing the design/print and build inc pics would be a nice read with my morning coffee.. ;)

Thebuttsniper
Posts: 5
Joined: Thu Jul 04, 2019 12:25 pm
Location: Oregon

Re: Y usb cable for power?

Sat Jul 06, 2019 4:04 am

Sorry if I don't find being spoken to like I'm a child funny. lol

I went ahead and tried that y cable and it definitely made it run a lot better! I was thinking my pi was just slow! so the details of the build are as follows!

Rpi 3 b+
63 key RGB mechanical brown switch keyboard.
10.1 inch 1024x768 monitor
a cheap o usb floppy and some cheap ol speakers

I started printing June 25 and it finished yesterday! it was 5 pounds of PLA
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Thebuttsniper
Posts: 5
Joined: Thu Jul 04, 2019 12:25 pm
Location: Oregon

Re: Y usb cable for power?

Sat Jul 06, 2019 4:05 am

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