On 06/02/18 09:19, RobH wrote:
> 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.

I realise that 1.58 amps is not enough power to do what I want it to, so
I'll get one of those fast charging cables.

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