On 06/02/18 02:19, Kees Nuyt wrote:
> On Mon, 5 Feb 2018 13:06:26 -0000 (UTC), Gordon Henderson
>  wrote:
>
>
>> If you have a screen connected then you'll see a yellow "lightning bolt"
icon
>> appear if the power is too low (and a red thermometer icon if it's too hot)
>>
>> 99% of issues like this is the power supply. Change it. Try another,
>> and if you have one, get your multimeter out and measure it when
>> it's powering a Pi.
>
> I agree, and I'd like to add that many USB cables have very thin
> wires and are too long, so they have too much resistence and cause
> unacceptable voltage loss. The buffer capacitors in the Raspberry
> Pi are too small to even supply short peaks current demands, so
> every peak has to be supplied by the power adaptor.
>
> I replaced those cables with a "charging cable", they just have
> thick power wires, no data lines, and haven't had any problems
> ever since (RPi 3, with an USB harddisk that draws 500 mA).
>
> Search on eBay for "Micro B USB Fast Quick Charge Cable 2.1A
> Android SmartPhone 18AWG" from Korea (or equivalent).
>
> Although the offer states 2.1A, they will carry 2.5A with ease.
> I prefer a length of 15 cm or 30cm.
>
> Not cheap, but really good.
>

I never thought that a USB charging cable would or could power up a pi3.
That is really helpful, thank you.

I have now attached a charging cable which I already have, and the pi 3
is up and running.
At the moment it is drawing 4.84 volts and 1.58 amps, but the red or
green leds are not lit up.

--- SoupGate-Win32 v1.05