PSU or Wifi problems ? Check your USB cables

[mikerr]

I've just had a morning of wifi problems with the pi3,
and traced it to the USB power cable - fine with a B+ - but the pi3 needed more juice.

All USB cables are not equal for power purposes, they vary massively by resistance.
I thought I had this sorted by using "thick" cables - but just found you can't rely that.

I now use an android app to help me check cables quickly:

Galaxy charging current:
https://play.google.com/store/apps/deta ... e&hl=en_GB

Here's two identical looking "thick" USB cables on the same 2A USB charger:

[evilkitty]

you can also use a multimeter to check the resistance on the power leads, well if you have a adapter to get the micro USB accessible enough, i have resorted to making my own cables from time to time, monoprice (the have both ebay and amazon accounts in addition to there own site) sells some good quality ones though (24AWG)

i tried making one with 20awg wire but the micro usb terminal could not handle it and broke after only a few uses

USB cables usually are in these grades:
31/31 (no name knockoff junk)
28/28 (low grade)
28/26 (moderate)
28/24 (high grade)

[blaablaaguy]

That app didnt work for me but another called ampere did

[mutley]

This was on kickstarter, seems like a great little gadget for testing USB Power Supplys & Cables
http://www.qoopow.com/

I've been using this
http://www.amazon.com/PowerJive-Voltage ... B013FANC9W

[jahboater]

you can also use a multimeter to check the resistance on the power leads, well if you have a adapter to get the micro USB accessible enough, i have resorted to making my own cables from time to time, monoprice (the have both ebay and amazon accounts in addition to there own site) sells some good quality ones though (24AWG)

i tried making one with 20awg wire but the micro usb terminal could not handle it and broke after only a few uses

USB cables usually are in these grades:
31/31 (no name knockoff junk)
28/28 (low grade)
28/26 (moderate)
28/24 (high grade)

The "official" Raspberry Pi power supplies have thick cables.
The old 5V 2A psu was 20awg, the new 5.1V 2.5A psu for the Pi3 is 18awg.
The 2.5A Pi3 psu will of course work fine for any Pi including the Zero.