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 donāt have a picture but will explainā¦
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 āunder voltage warningā 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?
Iām having the same problem 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, thatās more that the OPās 200ma, but this thingās rated at 5A. My neopixels donāt draw that much Itāll drop with well under 1A sometimesā¦
Note that I switched it out for a 5V BEC rated at 3A and it has no troubleā¦ I might switch to that, but Iād like to know if thereās something weird I should know about for this design? I have a few of these Iāve been using, but normally Iāve apparently gotten away with it.
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 āmight be dying over timeā. 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 āworseā over time, however itās not being consistent. I plugged it back in to check and it was 5Vā¦ then 4.99Vā¦ I couldnāt get it to misbehave, and I was wondering if something odd had happened, then it went down to 4.7V or soā¦
The input is 13.3V, big motorcycle lifepo4. I figured youād ask about Amps (goes and measures)ā¦ looks like < 0.9A. Itās āworseā with the LEDs āonā, 4.7V (closer to the 0.9A, though it never actually got that high), and ābetterā with the LEDs āoffā, .2A or so (closer to 4V).
As mentioned, using a little R/C BEC rated at 3A I donāt have any voltage drift at all.
I didnāt 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 ābetterā with the LEDs āoffā, .2A or so (closer to 4V).
I think this was just a typo and you meant 5V, but can you confirm that?
Hi, Iāve 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 robotās 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 ā it runs but thatās at the very bottom of its acceptable range. I havenāt measured the current consumption but it wouldnāt 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.
Iām guessing thereās no way to adjust the output of the regulator.
Iāve 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 5.1Vā¦
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.