The Apple charger is very good but isn't the best.
http://www.righto.com/2012/10/a-dozen-u ... le-is.html
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Richard-TX
- Posts: 1549
- Joined: Tue May 28, 2013 3:24 pm
- Location: North Texas
usb chargers - lab tests
Richard
Doing Unix since 1985.
The 9-25-2013 image of Wheezy can be found at:
http://downloads.raspberrypi.org/raspbian/images/raspbian-2013-09-27/2013-09-25-wheezy-raspbian.zip
Doing Unix since 1985.
The 9-25-2013 image of Wheezy can be found at:
http://downloads.raspberrypi.org/raspbian/images/raspbian-2013-09-27/2013-09-25-wheezy-raspbian.zip
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FTrevorGowen
- Forum Moderator
- Posts: 5621
- Joined: Mon Mar 04, 2013 6:12 pm
- Location: Bristol, U.K.
- Contact: Website
Re: usb chargers - lab tests
Not quite "lab tests", but I've performed some "current load" measurements of a number of U.K. style USB chargers over the last 18 months or so and, FWIW, the results can be found here:Richard-TX wrote:The Apple charger is very good but isn't the best.
http://www.righto.com/2012/10/a-dozen-u ... le-is.html
http://www.cpmspectrepi.webspace.virgin ... plies.html
and here (including an Apple one and its "clone"):
http://www.cpmspectrepi.webspace.virgin ... dPSUs.html
Trev.
Still running Raspbian Jessie or Stretch on some older Pi's (an A, B1, 2xB2, B+, P2B, 3xP0, P0W, 2xP3A+, P3B+, P3B, B+, and a A+) but Buster on the P4B's. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm
Re: usb chargers - lab tests
I tried also today with LM2576-ADJ. I was using a 2.2 ohm/25 W load resistor which gave a current of about 2.2 A. That was only about 4 hours test. The LM2576 can give a current of up to 3 A, so should try a smaller resistor too. The input voltage to the regulator was taken from a solid 12 V power supply. The regulator starts to get hot at these current levels and a heat sink is needed. RPi B alone takes 0.4 - 0.5 A. With a WiFi dongle and a USB hard disk the total current stays below 1 A in my case.