Core Electronics Forum

RasPi power supplies. UNDER VOLTAGE!

(As though I don’t have enough problems just now)

Back story:

I had a RPZ(W) working happily with a Blinkt LED strip on it. All working happily.

I made a mistake and updated to BUSTER. (the $hit then hit the fan)

So?

I eventually replaced the Z(W) with a 3B(+) (Not sure about the +)

Booted all sweet. Fan keeping it cool. Not really needed, but as it was already there I left it.

But the LED strip was missing because of mechanical problems between the Z and 3B.

Today I got some jumper leads just to test getting the LED strip working.
Carefully I put the leads and powered it up. Seemed to be ok. A couple of LEDs wouldn’t turn off - or more so: stay turned off.

Now:

All looking good (or seemingly) I put it back in place and… (drum roll)
Failed. :frowning:

Took it back out checked things.
UNDER VOLTAGE. ARGH!

So I need a RasPi power supply that can supply more current.
The one I have now is 2A. Yes, I know there are “bigger” ones.
But there’s the twist.

More current, but not in size.

So the one on the left is the one I have. 2A. The one on the right has more output, but is bigger.

(Gotta hate power boards)
(Oh, that’s a whole other set of problems)

So I need one which isn’t wider/fatter than the one on the left.

Open to ideas. Short extension cord… cringe… At a pinch.

1 Like

Hi Andrew,

There’s a good to fair chance you need more voltage, not more current. It’s likely that little plugpack is not capable of the same standards of line and load regulation as the official Pi supply is because they’re designed for different purposes.

If you want/need to use a power source other than the official one, your safest bet is to assume the official supply specifications are the same as the device requirements (5.1V ± 5% ie. 4.85V - 5.36V for a Pi).

If your supply is dropping below 4.85v (which is actually within the USB specification) you’re likely pushing the limits of what the Pi can operate on.

There’s a good discussion of this issue here:

Sometimes if I need a wider gap on my power board, I find a double adapter like this is quite handy:
image

5 Likes

Hi Andrew,

The one on the right looks like (from a distance) a proper RPI 5.1V PSU, so it should be fine. The first thing I do with my RPI PSU’s of that type is grab a pair of pliers and snap the sides off

image

Besides, you don’t truly own something until you void the warranty!

8 Likes

(Love the double adapter)

Yeah, I steer clear of them.

Both are official power supplies. :frowning:

I’ll now read the other thread.

6 Likes

Yeah, I forgot that. :wink:

I’ll have a try at it soon.

If it works, all will be good.

7 Likes

Well, good news!

I cut the lugs off the official PSU and plugged it in.

All working with LED strip working.

Woo Hoo!

One (of many) problems solved.

5 Likes