Mini360 get's super hot, why?

Hi guys,

I am new to Arduino and this forum, so bear with me if I do something wrong :wink:

I have two battery, both 11.1v, one 1,5A and other 6A
I am connecting the 1.5A to the Mini-360 and check the output voltage to set the output voltage to 4v to 5v(going to later feed it to my small DC motors).
But now I am at the phase of setting the potentiometer on the Mini-360 to get the proper voltage result.

It gets so hot after a few minutes(perhaps even in 1 minute) which I cannot even touch.
Is it normal? or I am feeding it with the battery that has too much current(Not sure this is the case since I did not connect anything to it to consume and generate the flow(except my volt-meter))

Since it gets super hot with the 1.5A battery, I scared to test it with the 6A battery and also scared to use it. My final project is going to go inside the box and has not the fan :disappointed_relieved:

Your advice is so much appreciated.
Thanks in advance.

Regards,
Amir

Since it gets super hot with the 1.5A battery, I scared to test it with the 6A battery

It will get no hotter with the high capacity battery as it does with the smaller one.

Basically it is getting hot because you are asking it to do too much or too little.

You could try extra output capacitors.

Try putting a resistor on the output for a load, say 100R. Some buck converters don’t like running into no load. Or connect it to your Arduino, that will draw about 30mA.

Hi Grumpy_Mike,

Thanks for the reply. It makes more sense now, to me.
Just to understand the capacitor and the resistor position, I create the sketch as the following picture. It would be something like the following sketch to be able to test the output voltage properly an dI can measure the voltage around R1, right?

Thanks again
Bests,
Amir

It would be something like the following sketch

Yes that would be the way to do it.

Have you looked at the MP2307 datasheet? The typical application in there shows 2 * 10μF capacitors on the input and 2 * 22μF capacitors on the output. I can't be sure looking at they image on Amazon but it doesn't look to me like they are there. If that's the case then try adding them, as close as physically possible to the MP2307, similar to what GM suggested.

How much current are your drawing?

It should not get very hot at all in normal operation.

Thanks Grumpy_Mike.

Hi PerryBebbington, it is new for me to look at the data-sheets and follow their best-practices. Thanks for pointing it out.
But, since I am not using the MP2307 directly and I am using the Mini-360 module, I thought they have simplified the MP2307 into the module that I can use it easily, right?
By looking at the board, it seems, to me, the 360-mini has almost the same number of capacitor and resistors as the MP2307's datasheet.

In my final plan, I will connect this to two DC motors in parallel. The amazon description says

Cover Flow: 0.35 – 0.4 A

.
But now I am trying to set the potentiometer properly and just connect the DC motors separately to see how they work. My previous attempts to feed this DC motor with my 11.1v battery has burned one DC-Motor :smiley:

Since I am not using the MP2307 directly and I am using the Mini-360 module, I thought they have simplified the MP2307 into the module that I can use it easily, right?

First, please remember I am working from a poor quality photo on Amazon, so could easily be mistaken. The makers of the Mini-360 can't simplify the design beyond what the manufacturers of the MP2370 specify without running into problems. If the required capacitors are not there then there you can expect problems. Those things are being sold for under €1 each, which means the manufacturer has made it as cheap as possible, possibly by skimping on component quality or leaving things out if they thought they could get away with it. You get what you pay for.

By looking at the board, it seems, to me, the 360-mini has almost the same number of capacitor and resistors as the MP2307's datasheet.

There may well be the same number of components, but are they the right components? Are the capacitor values the ones shown on the datasheet? I can't tell from the photos, but I suspect they are not. Maybe someone else reading this can tell and will reply.

Hi,
Mini360;


2307d.jpg
Tom... :slight_smile:

2307d.jpg

Are the capacitor values the ones shown on the datasheet?

It is not only the value but the type/quality of the capacitors. For this sort of work you need a low ESR ( effective series resistor ) type and these are more expensive. So even if the capacitors are there they are not likely to be good enough.

My previous attempts to feed this DC motor with my 11.1v battery has burned one DC-Motor

Which tells you that the motor is not designed for this high a voltage. What does the motor's data sheet say?

Are the capacitor values the ones shown on the datasheet? I can't tell from the photos,

No one can tell the value of a capacitor from looking at it let alone the dielectric type. But the input and output capacitors are bigger than the others so that would suggest a bigger value / voltage rating than the others.

Remember here the problem is that it is getting hot with no load. It would not be the first buck converter that didn't like having no load, or having load currents that trigger instability. They are very hard to design, especially in isolation like this one is.

Hi,
Motor spec.

Product description
Pack of 10 130 Micro DC Motor 3 V – 6 V 8000RPM
Feature:
Material: ABS (Acrylonitrile Butadiene Styrene) impact-resistant material
Hardware: Nickel Steel
Nib: Nickel-plated steel
Rivet: No
Wire: 1007 # 26AWG
Exposed wire length: 150 mm x 3 mm
Gear and the propeller shaft:
Length: 25 mm
Diameter: 21 mm
Shaft Diameter: 2 mm
Shaft Length: 9 mm
Voltage: DC 6 V
Main Dimensions: 25 x 15 x 20 mm
Motor Shaft Length: 9 mm, Diameter: 2 mm Shaft
Rated voltage: 3 V
Cover Flow: 0.35 – 0.4 A
3 V speed: 20000 rpm
6 V speed: 40,000 RPM
Package Content:
10 x engines

Basic 3V hobby motors.
Tom… :slight_smile:

Thanks PerryBebbingto, Tom and Grumpy_Mike for the replies.

Dear Grumpy_Mike, I have tried that schema you have said, but with 1kR which I had at home and still cannot put my finger on it for more than 5 seconds.
Is this one normal?

I appreciate your guys' help.
Amir

amir_6:
Dear Grumpy_Mike, I have tried that schema you have said, but with 1kR which I had at home and still cannot put my finger on it for more than 5 seconds.
Is this one normal?

No, it's not normal, it should be no more than slightly warm, certainly not too hot to touch (unless you have super sensitive fingertips :o )

Thank PerryBebbington,

I don't think I have a super sensitive skin :wink:
Attached my Board just to make sure I am doing it right?

Thanks again

have tried that schema you have said, but with 1kR which I had at home

Well 1K at 5V is a 5mA load where as 100R at 5V is 50mA load so you are testing a different part of the current load graph.

It should not get hot at all with this load if it is designed correctly but it seems it is not. A heaver load might find a spot where it is stable. If you are lucky then it might be stable at your final required load, otherwise conclude they are crap, leave a bad review and try and get something better from a more reputable supplier.

These tiny boards probably have undersized inductors, so will not handle the full rated current the chip itself can
handle. Also the boards themselves are too small to act as a pcb heatsink so will inevitably run hotter than larger modules.

Hi,
Can you show us a picture of the underside of the 360 please?
Did you solder the correct solder jumper only?

Thanks, Tom… :slight_smile:

Thank you all for your help.
Really appreciate.

Hi Tom,
I have taken a picture:

But, I didn't understand the soldering part you have mentioned, there is no jumper in the mini-360, is there?

Amir

MarkT:
These tiny boards probably have undersized inductors, so will not handle the full rated current the chip itself can
handle. Also the boards themselves are too small to act as a pcb heatsink so will inevitably run hotter than larger modules.

Hi Mark,
I think I am just putting 5MA current to it but the mini-360 said:

Output current: nominal current 1.8 A (3A MAX- cannot be extended).

This seems to be in the scope, but I will try what Grumpy_Mike said to put less Resistor to have more load to see how it behaves.
Actually, that is why I wanted to compare with others' experiences to see whether it is the problem in just my module or all have the same problem or my wiring have a problem.
Thanks all.

amir_6:
Thank you all for your help.
Really appreciate.
But, I didn't understand the soldering part you have mentioned, there is no jumper in the mini-360, is there?

Amir

Some of the units I have come across with that regulator have solder pads underneath that need jumping.
Here is a link to a guy who did some testing of those units and got varying results.
https://www.epanorama.net/blog/2017/06/17/small-switch-mode-psu-module-mps-mp2307-fail/
Tom... :slight_smile:

Thanks Tom, You have helped me a lot man!
I have seen all of his videos.
It seems he has faced the same problem as I faced. He has mentioned as a conclusion:

I would not recommend this module under 50mA load as linear regulator will do a better job in that range, but going over 50mA this regulator will work excellent. Also recommending additional electrolytic at least 100uF/25V at the input.

I have tried to connect to my DC motors as well, but it gets really hot so fast. Considering my DC motor has:

Cover Flow: 0.35 – 0.4 A

Which shouldn't be an issue as he has said.
Still wonder.
Again thanks a lot.