Mini Voltage Regulator For Mobius Quadcopter RC Model Review

I recently discovered this very neat voltage regulator on eBay, it’s very small (size of a coin), and it’s very light weight as well (2 grams). That makes it perfect for RC planes and quadcopters. It can convert 4.5V to 28V (2S, 3S, 4S all the way up to 7S) battery to 0.8V to 20V (which includes the most used 3.3V, 5V, and 12V) by the trim pot. The maximum current it can provide is up to 3A. Most importantly, it’s only $3 a piece, which is cheap for a voltage regulator!

3A Mini Voltage Regulator Spec

Not only for multicopters and RC planes, It could be great for general use as well, for example as a mobile external power source (with some lipo batteries), use it to power your mobile phone, or your Gopro camera etc. Let’s have a look at the specs.

3A-mini-back 3A-mini

  • Input voltage: 4.5-28V
  • Output Voltage: 0.8-20V (adjustable)
  • Output current: rated current 3A(MAX).
  • Switching Frequency: 1MHz
  • Output Ripple:less than 30mV
  • Efficiency:96%(max)
  • Operating temperature: Industrial grade (-40 C to +85 C)
  • Module Properties: Non-isolated step-down module (buck)
  • Size:22*17*4mm
  • Weight: 2g

Some of my thoughts

I use it to power my video transmitter and both my FPV camera (Sony 600TVL) and Mobius Camera, off my 4S main Battery. I have to say it performs decently. With a LC filter the signal and video quality is excellent, voltage ripple is reasonable, no worse than my the other chunky voltage regulator (about the same specs, only larger and heavier ~ 15g).

lc-power-filter1

voltage-regulator-power-filter

 

Although it can provide up to 3A of current, I would not recommend to use it for anything above 2A without a heatsink. I use it to output 1.5A and it’s already getting very warm. Also there is quite a big inductor on the regulator, which will generate some electro-magnetic field around it. So remember to keep it away fromall of your sensors on the flight controller (mag/compass//gyro/acc sensor).

Mobius Action Camera External Power Source

The reason I started digging is because I needed a stable power source for the mobius camera. With the built-in Lipo battery, it can only record for 60 to 80 mins. If you want to record any longer, External power source is required.

These cameras can draw up to 0.5A which is way more than the 808 cameras. I could just use the 5V BEC off one of my spare ESCs, but I am worried about the voltage ripples and noise from these power source. I am sure it will work too and save you some troubles, but it’s just more reliable to have a dedicated voltage regulator for all the FPV equipment. Do NOT tap power off your flight controller for the mobius though, try to connect the camera power cable directly to the ESC 5V output. That’s because you don’t want to run a large current though your flight controller, which could potentially fry it.

How to buy it?

Search for “Mini 3A voltage regulator” in eBay.com, and find the cheapest one! :-D

20 thoughts on “Mini Voltage Regulator For Mobius Quadcopter RC Model Review

  1. Callum

    Hi Oscar, I purchased a few of these recently but I am struggling to get them to do their job.

    I wired them up like this Just confirming all I have to do to change voltage is to screw the screw left or right?

    My wiring is exactly the same as rcmodelreviews http://imgur.com/XKVLpHh. (the same as rcmodelreviews review video, I don’t have a pic of my own on hand right now.)

    When I plug it in I measure 12.4v (straight battery voltage) coming out.

    When I turn the screw I have zero change in voltage.

    What am I doing wrong? Frustrated to be stuck on what seems like such a simple part of this build.

    Reply
    1. Oscar Post author

      are they behaving all the same? if just 1 then i would say might be a faulty knob…
      but if it’s happening to all, then it’s probably how you turn them? or just they have a defective batch?
      i have used more than 10 of these and i have never seen this problem myself

      by the way, I recommend joining this forum, it’s very useful and there are lots of helpful people there. I am a daily user too :) http://intoFPV.com

      Reply
      1. Callum

        Hi Oscar, thanks for your reply.

        I bought 3 and have tested 2 so far. All I have to do is turn that big outer screw right?

        I contacted the seller and they told me to use a very small screwdriver to turn the inner screw?????

        I will join that forum you mentioned, thank you!

    2. jeff

      Do you have the output / input reversed? … cause mine did the same thing until I realized I wired it backwards, lol!

      Additionally, these regulators put out decent current … I am running 4 Mobius boards off one of these units … I did mount it externally so prop air will cool it.

      Reply
  2. max

    hi oscar,

    i also discovered this regulator as well and picked one up.
    i hooked it up to my multimeter and the 12 volt rail of an old pc psu. when i turn the potmeter the output voltage’s range is only 0.8 to 1v, way of the desired 5v.

    now i am wondering how you were able to get a voltage of 5v out of it.

    thanks

    Reply
  3. Alexandru

    Hi,
    What if to use an UBEC 12V instead of LC filter + Voltage Regulator? As I know LC filter, filters noise coming from ESCs. I’m not sure for 100%, but I think OPTO ESCs don’t make noise. So just a voltage regulator should be fine. And I was wondering if I will use an UBEC for FPV instead of voltage regulator. That will give me filtered 12V… Isn’t it?
    Thanks.

    Reply
    1. Oscar Post author

      HI Alexandru, that’s a very idea, I will look around for a light weight 12V UBEC and test it :)
      But i think LC filter is still required possibly at the UBEC output

      Reply
  4. Tunedis95

    Great blog and very informative just as everyone else said. Kuddos! Building my first quad following your blogs.

    Question, how do you adjust the output on this voltage regulator? Use a phillips to turn that “screw”. Moniter with a voltmeter on the output side as adjusting? Just trying to be crystal clear.

    Thanks again for all your time and effort, hope to do my part with my build and help others too.

    Reply
    1. Oscar Post author

      Glad you enjoy it! :D
      Yes, you are correct.
      There is a knob you can turn to adjust the output voltage, using a philips.
      connect the output to a voltmeter, or a multimeter, to monitor the voltage.
      Make sure you wrap the regulator with heatshrink or something similar, just to avoid the output voltage get accidentally changed.

      Reply
      1. Tunedis95

        Ahhhh. Good words of wisdom. As far as the rest of the electrical components, I will be applying a clear Urethane Seal Coat to prevent any shortages from blades of grass and what not. I was Planning on spraying this regulator too. Spray alone i’m sure will keep adjustment screw in place.

  5. Colin Conway

    Oscar,

    Great site by the way, a wealth of knowledge here. I’ve built two quads since reading your blog, both working excellently.

    Quick question for you, what order is best for the voltage regulator and power filter? I presume your battery is connected to the regulator and the power filter wired next and then your fpv camera system???

    Reply
    1. Oscar Post author

      Hi Colin, that’s what I always like to hear :D

      I prefer to place the filter before the voltage regulator, because when power filter (LC filter) is removing noise, you will see a voltage drop at the output of the filter, but the voltage regulator would not mind the drop, and will still output the desired voltage (or close enough). But if you have them the other way round, the voltage drop could be noticeable and it might upset the devices you are running on your regulated voltage.

      Apart from this, there are also performance concerns (noise-removing result) that suggests LC filter should be placed before the regulator. But I am not familiar with this myself.

      Reply
      1. Colin Conway

        Excellent. Thanks a million. Hooking up my FPV system to a 4S battery today so hopefully it works out alright.

  6. Tony

    Thanks for the interesting article. I have a few questions. Except being cheaper, how is this device different from a bec? Is it a switching regulator versus a linear regulator? In the photo showing the heat sinks, it looks like a different board (perhaps a higher resolution resistor for setting the voltage?) . I guess it is the one from this page: https://oscarliang.com/linear-regulator-vs-switching-regulator/. What is the difference between the two devices?

    On the device pictured on this page, which component would you add a heat sink to?

    Thanks!

    Reply
    1. Oscar Post author

      A few reasons:
      – cheap (as you pointed out)
      – adjustable output voltage
      – wider input voltage range than a BEC
      – smaller and lighter

      In the post, the one with heatsink, is my old linear voltage regulator.
      If you need to put a heatsink, put it on the 8 pin black chip.

      Reply

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