Re: 5V power supplies #hampi


Good info.

Also consider lead length and gauge -- too many folks grab random supplies that are just not up to the load.

Many of my Pis for Amateur Radio have a radio interface HAT (DRAWS™) with a built in 9-15VDC to 5.1 VDC supply and feed the 5V to the 5V rail via the GPIO. This eliminates some of these issues.

On Tue, Nov 17, 2020 at 2:12 PM Charles Albert <mrcwa2@...> wrote:
When a power supply is/is not 5V:  Guys, I have experienced the following error on my 3B+ machines- - Low Voltage Warning, check power supply- -when using power supplies 5V, 2.5A.  2 of my 3B+s have given that warning. Also, the video degrades when watching live video.  I have worked with power supplies on the zero w, 3B+ and 4B machines. The 5V, 2.4 A supply is OK with the zero w.  I obtained a few 5.25V, 3A supplies and the 3B+s work perfectly each time. Note, that on the input of the pis, there is a zener and a 47uF capacitor, no other conditioning or regulating. When the 3B+ has both USB ports loaded with the mouse and keyboard, a HDMI port sending video and audio to the monitor, in this case either a 7" or 12" monitor, and the LAN cable connected to a Netgear router/switch; there is a load on the power supply in addition to the machine itself.  After studying the effects of the power supplies on the 3B+, I have come to the conclusion that for optimal operation of a fully loaded 3B+, use NOTHING other than a 5.25V, 3A power supply. Interestingly, the Canakit 5.1V, 3A supply which came with the 4B works perfectly with the 4B.  that other 0.1V obviously helps with the 4B. I wouldn't think about putting the 4B on a 5V supply.  So tolerances matter. I hope this is usable info for y'all, 73 Charles A. KK4AC, incidentally, the 5.25V 3A supplies can be had from Amazon for about $11.00

John D. Hays
Kingston, WA


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