D24V50F5 5v 5A voltage output


I have just purchased a D24V50F5 through my local distributor.

Input voltage 12v with 5A available.

A no load output voltage is 4.98 Volts
A load of anything more than 200mA results in an output voltage of around 4.5 Volts.

I am trying to power a raspberry pi, but the raspberry pi displays the under voltage warning.

Am I doing something wrong? Or have I miss understood the step down voltage regulator?

Thanks :slight_smile:


I am sorry you are having trouble with your regulator. With that input voltage that regulator should be able to handle much more than 200mA without the output voltage dropping to 4.5V. What type of supply are you using? How are you measuring the current draw of your Raspberry Pi? Are you measuring the 4.5V on the output with a multimeter? Could you post pictures that show your setup and how you are connecting the regulator to the Pi?



I have tried with two different power sources. 12v bench top supply and a fully charged 12volt Sealed Lead Acid battery 10Ah.

Both wired directly to regulator (one at a time).

I don’t have a picture but will explain…

Ground out of regulator connected directly to Ground pin on usb male header.
+5v wire connected in series through multimeter and then to +5v pin on male header.

Then another multimeter connected across the regulator.

I have tried another 5v source into the usb cable and connector, and do not see any voltage drop, ruling out the cable voltage loss etc.

I purposely used thick wires to overcome any voltage loss.

Another test was done using a large adjustable resistor load bank, so was able to load the regulator a step at a time and noticed the voltage decrease at around 200mA of load.

The Raspberry Pi 2 also displays an ‘under voltage warning’ on screen as well.

You mentioned that you noticed the decrease in voltage at a load of 200mA. Did the voltage suddenly drop at that current level or did it gradually fall as you increase the current? What size increments were you increasing the current in? Your test setup without the Raspberry Pi sounds fine, but it is hard to really know without seeing pictures of it. Could you take pictures of that test setup and a close up of the components on the regulator?


I’m having the same problem :frowning: It might be dying over time. With a tiny bit of a load (Arduino with nothing going on), it drops to 4.7V. With a bunch of neopixels (30) it drops to 4.4V. Granted, that’s more that the OP’s 200ma, but this thing’s rated at 5A. My neopixels don’t draw that much :slightly_smiling_face: It’ll drop with well under 1A sometimes…

Note that I switched it out for a 5V BEC rated at 3A and it has no trouble… I might switch to that, but I’d like to know if there’s something weird I should know about for this design? I have a few of these I’ve been using, but normally I’ve apparently gotten away with it.

Hi, kresty.

What are you using to supply power and at what voltage? Have you measured the current draw of your Arduino and Neopixels? You mentioned the regulator “might be dying over time”. What do you mean by that? Did it used to perform differently? Could you post pictures of your test setup and close up pictures of the problematic regulator?


I think it used to perform differently. I thought it was getting “worse” over time, however it’s not being consistent. I plugged it back in to check and it was 5V… then 4.99V… I couldn’t get it to misbehave, and I was wondering if something odd had happened, then it went down to 4.7V or so…

The input is 13.3V, big motorcycle lifepo4. I figured you’d ask about Amps (goes and measures)… looks like < 0.9A. It’s “worse” with the LEDs “on”, 4.7V (closer to the 0.9A, though it never actually got that high), and “better” with the LEDs “off”, .2A or so (closer to 4V).

As mentioned, using a little R/C BEC rated at 3A I don’t have any voltage drift at all.

I didn’t notice anything visibly wrong with the part.

If the problem is intermittent, it might be due to a loose connection or solder joint. Could you post pictures that show the soldering and connections?

Your battery sounds fine, but depending on how your connections are made, a 0.3V drop with a load close to 1A might not be that strange. Where are you measuring the output voltage of the regulator? Could you post pictures that show your test setup? When you switch to powering off your BEC, do all of your other wires and connections stay the same?

and “better” with the LEDs “off”, .2A or so (closer to 4V).

I think this was just a typo and you meant 5V, but can you confirm that?


Hi, I’ve got a similar setup (hence not starting a new topic).

I have a Raspberry Pi based robot that uses a Makita 18v 3Ah power tool battery. My bench supply is a Toshiba 19V 6.32A AC converter, basically a very large laptop power supply. I use a Pimoroni ADS1015 AD converter for the robot’s low voltage sensor as well as a good quality multimeter for checking that the ADS1015 is calibrated properly. I generally run a Python script on the robot that displays the battery voltage (around 19.3V typically) and the output from the regulator.

Today I received a Pololu D24V22F (the 2.5A version) in the mail and installed it on the robot as its 5v supply. Using the bench supply, with the load of the Raspberry Pi and a small number of sensors the D24V22F seems to consistently put out 4.71-4.75 volts. To confirm, I also ran it from the Makita battery, and the result is the same. As the OP wrote, 4.75v is too low for the Raspberry Pi – it runs but that’s at the very bottom of its acceptable range. I haven’t measured the current consumption but it wouldn’t be much higher than the Pi itself, maybe 100mA more. This is before I turn on the motors or do anything robot-like. Running a test suite on the robot (that uses LED matrix displays, the motor controller,etc. drops the voltage temporarily as low as 4.69 volts. But quiescent usage of the Pi and a few sensors seems to rest at 4.73v.

I’m guessing there’s no way to adjust the output of the regulator.

I’ve recently ordered the D24V50V5 and expect it in the mail soon. Do you think it will make any difference? Or should I find some kind of tunable regulator and tweak it to get exactly 5V? Noting that the Pi 3 B+ actually likes about 5.1V…

Thanks for your help.


It sounds like you are powering a lot of different components, so it seems conceivable that you might be drawing more than the D24V22F5 can supply, in which case replacing it with the D24V50F5 will help. However, problems like this can also be caused by other things, like long wires or poor connections causing a voltage drop before your load. If you post some pictures of your setup and tell me how you are measuring the voltage from your regulator, I can take a look to see if there might be any other problems.

- Patrick