I have an Anker Atom 3 4-port power supply (https://us.anker.com/products/a2045). In the USB-C port, I've got a USB-C ub plugged in that goes to my chromecast w/ Google TV as well as a web cam for a cheap video conference setup. I'm also trying to use one of the USB-A ports to power a Raspberry Pi 3b, running the lastest OS with Pi-Hole and Zerotier on it. However, it's giving me a low voltage warning. Everything seems to run fine, but would be nice to get rid of the warning.

Tech specs for the PSU say that each of the USB-A ports should supply 2.4A@5V (4A total), so with noting else plugged in, it should be enough for the Pi. So I don't understand why I'm getting the LVW. Any thoughts?

  • 1
    I have a few Anker supplies and I stopped buying them for this reason. "I don't understand why I'm getting the LVW" To be tautological, you are getting the low voltage warning because the voltage detected by the SoC is low. Setting aside the possibility of defective firmware (which provides the warning), it is pretty simple. Of course, one can believe it is raining without understanding why it is raining:
    – goldilocks
    Commented Dec 16, 2021 at 15:44
  • 1
    Realistically, power supply voltage/amperage ratings are idealized, and will not reflect the fact that, eg., the supply cannot keep the voltage totally level during periods of rapid current fluctuation (such as a working microprocessor based device tends to produce). Over long/thin USB cables are frequently the problem, as you will observe if you persuse the umpteen ^10 other questions here that are much the same.
    – goldilocks
    Commented Dec 16, 2021 at 15:47
  • @goldilocks: Not to belabor this umpteenth LVW question, but the linked question listed in the closure notice asks about the "official" supply, whereas this one is for a battery. Would a "Community" answer be appropriate for this LVW FAQ?
    – Seamus
    Commented Dec 18, 2021 at 17:59
  • The "loaded vehicle weight" FAQ?!? Anyway, it's actually not a battery, it's a multiport charger. In any case, I think the value of using the "official supply" question makes it clear that there is no 100% guarantee any 5V supply will work -- which is more or less my experience. Pis are very fickle this way and I think it is probably their own fault but we have to deal with that or find something else. Often enough the warning never amounts to anything. It does put someone with only 1 new Pi and the official supply in a bit of a conundrum: Do I return the Pi, the supply, or both?
    – goldilocks
    Commented Dec 18, 2021 at 20:34

2 Answers 2


If you get a low voltage warning it is because the voltage is low!

Like the hundreds of similar questions on this site the answer is the same.

Either the "power supply" is inadequate or the wiring is inadequate (or both).

The world is awash with poor chargers, which are DESIGNED to change batteries.

Try an official power supply.


Cable also can be a problem. Bad micro-usb cables can also cause low voltage. Very thin wires, long cables, blackened and distorted usb connection causes voltage drop. Try some qualified micro-usb cables.

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