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That God %$#@ Lightning Bolt



  • @classicgmr https://www.amazon.com/Mackertop-HSTNN-LA43-PA-1150-22HA-779573-001-761247-002/dp/B01HB44IE6

    This is the power supply that I'm using with my pi3, I am also using the super kintaro case. I have had no issues with this power supply and I'm overclocked.



  • @jonnykesh said in That God %$#@ Lightning Bolt:

    USB cables are just not designed to carry the Amps that a Pi needs.

    Do you have a citation on this? I would think that the wire gauge of USB cables is more than enough to carry the amperage needed.



  • @markwkidd A citation? Really?
    Considering most USB chargers output no more than about 1.2A I would say that is pretty much a given. Why waste money on cables capable of more?
    You might get lucky and actually get one capable of delivering it. Certainly not in my experience.



  • @jonnykesh said in That God %$#@ Lightning Bolt:

    @markwkidd A citation? Really?
    Considering most USB charges output no more than about 1.2A I would say that is pretty much a given. Why waste money on cables capable of more?
    You might get lucky and actually get one capable of delivering it. Certainly not in my experience.

    Yes, when you are making electrical engineering claims that don't make sense, yes I'd like to know how you determined that USB cables can't carry the required amperage since you are advising others based on your determination.

    If you have never had one that could handle the amps, just say that.



  • @markwkidd I just did.
    I'm also making a recommendation based on best case scenario. Are you employed by "big USB" cable or something?
    Obviously you know that not all "wall warts" will output what they claim. They certainly won't if you team them up with a poor quality USB cable.
    I feel like I am being attacked for giving the best advice I can. As always advice is just that, my experience plus my knowledge of electronics. Take it or leave it. YMMV.



  • As an electrical engineer I would doubt whatever the pi is drawing is going to be an issue for the wire itself, but that doesn't mean the wire isn't the problem here either. Amperage plays into it, but it is not directly what this error is about. It's an undervoltage error. The wire doesn't have to be overheating and melting off it's insulation to be failing in this application. It could simply have just barely enough resistance, that with a healthy current draw from the pi, the voltage drop across it is enough to make the lightning bolt come up. Simple wall warts also see their voltage sag under load.

    What you should do is take a multimeter and measure the 5V where it's coming into the board. The connector 5V and ground are easily accessed from the bottom side of the board under the connector, but take care not to short anything to 5V. Try this under load and powered down. You should see a difference. If it is clear the voltage at the pi is too low you can only try a thicker and/or shorter cable that is less resistive, and if that doesn't do it then you're power supply just can't maintain the correct voltage under load.



  • @jonnykesh Not all usb cables are made equal. They can vary in awg. They are not "ideal", but they are usable if you get the lowest awg size you can find. The official pi ac adapter uses 18awg so I suppose you can get away with 20awg.



  • @quicksilver Looks like I may have to go with a hardwired 3A. I've had no luck with all these USB detachable chargers.

    The 2.5A PSU CanaKit (hardwired) gives me "Da Bolt" on occasion. I also have a 2.5A Viaboot hardwired that isn't any better.

    Will check out your PSU next time I put in an Amazon order. :)



  • @classicgmr I have tested that power supply while running cpuburn-a53 which is a test that runs the CPU at full speed. It's a great way to test your pi to see if your cooling and power needs are adequate. It passed without getting the low voltage warning, my 2.5amp canakit did not pass however.



  • @markwkidd said in That God %$#@ Lightning Bolt:

    Do you have a citation on this?

    This may help.



  • @rbaker said in That God %$#@ Lightning Bolt:

    @markwkidd said in That God %$#@ Lightning Bolt:

    Do you have a citation on this?

    This may help.

    Thanks! So we have manufacturers skimping on copper and violating the USB spec by reducing wire gauge.

    From what I'm reading there, it's still no reason to avoid one style of power supply over another. Just like controllers, cases, and anything else that's mass produced there are bogus cables out there. Source one from a reliable vendor or take chances with knockoff or out of spec gear.



  • @clippercm I agree! I'm also not a fan of the whole USB connectors used for power on the Pi's. In the USB 1.0 and 2.0 specs, a standard downstream port is capable of delivering up to 500mA (0.5A); with USB 3.0, it moves up to 900mA (0.9A). I wish they would have gone to a barrel power connector like most laptops use.


  • administrators

    @markwkidd yeah AliExpress is a terrible source for proper usb cables. My hub was proper but anytime the USB was plugged automatic lightning bolt.



  • If you have a couple multimeters (or a o-scope better yet) connect them to the output of the power source and look to see if the current is limited and tops out at a certain number or see if you get voltage drops when a load kicks in. I’m guessing cheap cables are the culprit, badly made cables made of cheap materials can act as an electrical shunt and cause unwanted resistance.



  • I cracked open a 2a power supply that I bought for my pi2 from some chinese website for like $5 a few yrs back because it was giving my pi2 the lightning bolt which it never had before. The wires from the plugs to the pcb were really thin and over time, because the way they got shoved in, the wires were getting loose. I replaced them with the thick kind from a dead pc power supply and it works again.



  • Corrupt Install after reboot

    I seem to have a problem with this version of the RPi, RPi3B. It seems that it is a beast of an energy hog where it needs a specific power supply that does not come with it. YES, I get the lightning bolt from hell. After using 6 different USB power supplies I still get the same problem. Did someone give RPiorg the specs of USB power?

    As I had mentioned above that I had used 6 different USB power supplies. 3 were rated at 2.1 Amps, 1 at 4.8 Amps, 1 at 850 MilliAmps and a portable power bank with a rated output at 1 Amp.

    The 3 different USB power supplys(ASUS, STAPLES and RADIOSHACK) that were rated at 2.1 Amps were 120volt mains plugs for charging cell phones. Using a "USB Doctor" and seeing the voltage from 4.8 to 4.9 and the current draw from 230-300 MilliAmps.

    The 1 USB power supply(blackweb) that was rated at 4.8 Amps(I would not recommend this) is a mains plug with 2 USB power outlets. Using a "USB Doctor" and seeing the voltage at 4.8 and the current draw from 230-300 MilliAmps.

    The 1 USB power supply(RIM branded Blackberry charger) that was rated at 850 MilliAmps is a mains plug with 1 USB power outlet. Using a "USB Doctor" and seeing the voltage at 4.8 and the current draw from 230-300 MilliAmps.

    The portable power bank(Circuit City/NEXXTECH) with a rated output at 1 Amp was the worst with using a "USB Doctor" and seeing the voltage at 4.7 and the current draw about 500 MilliAmps.

    After installing retropie on the same LEXAR 16GB MicroSD about 10 times to run on my RaspberryPi 3B. I gave up to come here to see if there is a soft hack to fix this problem of corrupted intalls. I am able to copy the retropie image version 4.4(I had tried 4.2 and 4.3 as well) to the 16GB MicroSD card and it will boot the RPi 3B into the kernal where I am able to update and transfer files and play the games that I loaded onto it. It looks like it shuts down properly when I select the menu option to shut down. When I try to reboot, the RPi 3B does not want to boot up again.

    Understanding what is going on here is the Lightning bolt effect(error). Yes I do see a lightning bolt show up but that is half of the problem. The other half is the system halts itself when it detects the power is low. Is this causing the corrupted installs that I've been suffering?

    I had used a different distro named OSMC and installed without any trouble and rebooted many times without any corrupted install.

    Is there a way to hard-write the RPi 3B to only complain of the voltage if it sees it below 4.5 volts? Is there a way to stop the system being halted on low-voltage errors?

    Buying a 2.5 Amp RPi-Certified power supply is NOT an option if this is the case because it should be included with every single RPi that was sold. Some people are actually having trouble with the RPi-Certified Power supplies not supplying a proper voltage. Just wondering if there is a decent fix for this problem.


  • Global Moderator

    @unrealduke So, in spite of the specs put up by the Raspberry PI team and their recommendations, you try a lot of chargers/power sources that are clearly out of spec, then you experience sd corruption and system shutdown because of it and then you still try to find a software solution because you bought your PI without a proper power source ?
    Get a proper power adapter, it's the only option.



  • @mitu, Show me a spec sheet that demands at least 5.2 volts for each piece of silicon on that circuit board. Did you even check the current draw ratings that I posted?



  • @unrealduke https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md

    The recommendation and the official power supply is 5.1V 2.5A. So buying anything below is a waste of time. Though, 5.1V is the required voltage. Amps can vary but must be at least 2.5A or higher. There is no reason to buy 1amp stuff. I bought the official pi power supply and have no regrets.



  • @all Show me a spec sheet that demands at least 5.2 volts for each piece of silicon on that circuit board.

    Honestly, this thing was is supposed to be USB powered. I probably have the exact same quad-core CPU in my cellphone running off of a 3.8 volt Lithium-Ion battery.



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