nachiketh
Posts: 45
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Raspberry Pi Power Source

Tue Sep 04, 2018 11:55 am

I'm currently powering the raspberry Pi from a 27V DC SMPS via a step down transformer having the following specification:

Code: Select all

Input - 8V-50V 
Output -  5V 3A(Max)
However recently the pi burnt out and i lost the board, this happend after it was running fine since the last few weeks. Is there any additional precautions I can take to prevent this from happening in the future, I am open to using a spike buster if required. any suggestions in this regard are welcome.

LTolledo
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 12:49 pm

Get the RPF recommended power supply unit. Simple as that.
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Come to me with 'problems' and I'll help you find solutions"

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nachiketh
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 12:58 pm

LTolledo wrote: Get the RPF recommended power supply unit. Simple as that.
Unfortunately I do not have a AC power in the environment where i'm using this RPi, hence I cannot use the RPF recommended power supply unit.

LTolledo
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 1:25 pm

How do you power the SMPS?

A step down transformer only works with AC sources.
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

pws
Posts: 92
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 1:38 pm

nachiketh wrote:
Tue Sep 04, 2018 11:55 am
I'm currently powering the raspberry Pi from a 27V DC SMPS via a step down transformer having the following specification:

Code: Select all

Input - 8V-50V 
Output -  5V 3A(Max)
However recently the pi burnt out and i lost the board, this happend after it was running fine since the last few weeks. Is there any additional precautions I can take to prevent this from happening in the future, I am open to using a spike buster if required. any suggestions in this regard are welcome.
Have a look at these: https://www.amazon.com/gp/product/B01GJ ... UTF8&psc=1

Just attach the OUTPUT of your 27V DC SMPS to the INPUT of this "buck converter", adjust the OUTPUT VOLTAGE, then attach the OUTPUT to the Raspberry Pi.
Last edited by pws on Tue Sep 04, 2018 5:51 pm, edited 1 time in total.

Brandon92
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Location: The Netherlands

Re: Raspberry Pi Power Source

Tue Sep 04, 2018 2:39 pm

nachiketh wrote:
Tue Sep 04, 2018 11:55 am

Code: Select all

Input - 8V-50V 
Output -  5V 3A(Max)
Can you provide more information about this power supply. For example what is the exact type?

nachiketh
Posts: 45
Joined: Wed Sep 25, 2013 4:54 pm

Re: Raspberry Pi Power Source

Tue Sep 04, 2018 2:46 pm

Brandon92 wrote:
Tue Sep 04, 2018 2:39 pm
nachiketh wrote:
Tue Sep 04, 2018 11:55 am

Code: Select all

Input - 8V-50V 
Output -  5V 3A(Max)
Can you provide more information about this power supply. For example what is the exact type?
This is the power supply i'm using: https://www.amazon.com/GERI-Converter-M ... c+to+5v+dc

hippy
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 4:42 pm

nachiketh wrote:
Tue Sep 04, 2018 11:55 am
recently the pi burnt out and i lost the board
If you could describe how your Pi was being used, what it was connected to, and how it "burnt out" - stopped working, burst into flames, started smoking, etc - it might be possible to suggest why that may have happened, what might have caused it, and how it might be prevented in future.

nachiketh
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 5:14 pm

hippy wrote:
Tue Sep 04, 2018 4:42 pm
nachiketh wrote:
Tue Sep 04, 2018 11:55 am
recently the pi burnt out and i lost the board
If you could describe how your Pi was being used, what it was connected to, and how it "burnt out" - stopped working, burst into flames, started smoking, etc - it might be possible to suggest why that may have happened, what might have caused it, and how it might be prevented in future.
the power related components and the fuse on the board are fried :? check the image below...

ImageImage

Ernst
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 6:23 pm

Could this be the result of a lightning strike ?
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nachiketh
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 6:44 pm

Ernst wrote:
Tue Sep 04, 2018 6:23 pm
Could this be the result of a lightning strike ?
I doubt that, there is another motherboard drawing power from the same SMPS which is working perfectly fine. :roll:

However a power shutdown happens every now and then. I'm guessing it's got something to do with a power surge happening when the power transmission resumes, causing it to spike the input voltage.

hippy
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 6:49 pm

nachiketh wrote:
Tue Sep 04, 2018 6:44 pm
I'm guessing it's got something to do with a power surge happening when the power transmission resumes, causing it to spike the input voltage.
Whatever caused the damage it seems to be a quite substantial adverse condition to have done that. Did the step-down providing 5V survive that ?

What else did you have connected to the Pi ?

nachiketh
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 6:56 pm

hippy wrote:
Tue Sep 04, 2018 6:49 pm
nachiketh wrote:
Tue Sep 04, 2018 6:44 pm
I'm guessing it's got something to do with a power surge happening when the power transmission resumes, causing it to spike the input voltage.
Whatever caused the damage it seems to be a quite substantial adverse condition to have done that. Did the step-down providing 5V survive that ?
Nope that's blown too.
What else did you have connected to the Pi ?
There is an ethernet connection connecting the pi to a switch and that's it, nothing else.

Brandon92
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Location: The Netherlands

Re: Raspberry Pi Power Source

Tue Sep 04, 2018 7:10 pm

Okay, can I also ask what for kind of 27V SMPS are you using. And did he survive? Because, it looks like the 5V supply didn't survive it and the 27V did get straight to you Rpi.

Back to you 5V power supply. I can't tell you if this is a good quility supply. Because, even on the manufacture side, they don't tell you what for kind of protection is avadable. And how stable the powersupply itself is and the tolerance are. And if you want a good powersupply you can take a look at this for example (note: this is the first one I could fine)

By the way, this is also a reason why I don't by product that don't give all the (imported) information. And the powersupply could be cheap, but now you need to buy another one and you are a Rpi down.

nachiketh
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 7:22 pm

Okay, can I also ask what for kind of 27V SMPS are you using. And did he survive? Because, it looks like the 5V supply didn't survive it and the 27V did get straight to you Rpi.
I'm collecting this information as that's a 3rd party supplier, will probably have this information in a day or two.
And if you want a good powersupply you can take a look at this for example (note: this is the first one I could fine)
This seems like a good fit, but getting a working product out of this buck converter would be time consuming I think, is there a temporary solution such as an external fuse which I can use which can cut off any power> 5v between my power supply and the pi.
By the way, this is also a reason why I don't by product that don't give all the (imported) information. And the powersupply could be cheap, but now you need to buy another one and you are a Rpi down.
Agreed! But I was in a little bit of a hurry and dint really think a buck converter would cause me such damage :? will make sure I have a good quality one going forward and have it designed myself.

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davidcoton
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 7:30 pm

nachiketh wrote:
Tue Sep 04, 2018 6:56 pm
hippy wrote:
Tue Sep 04, 2018 6:49 pm
Did the step-down providing 5V survive that ?
Nope that's blown too.
Was the power connected through the microUSB connector or via the GPIO connector?

In either case it might be difficult to determine cause and effect of the two faults, but a step-down fault that applied too much voltage through the microUSB should have been "safe" for the Pi, because the protection zener diode would work long enough the open the polyfuse. Worst case the protection diode itself fails, but can be replaced. In this case it looks like catastrophic failure of both diode and polyfuse.
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nachiketh
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 7:38 pm

davidcoton wrote:
Tue Sep 04, 2018 7:30 pm
nachiketh wrote:
Tue Sep 04, 2018 6:56 pm
hippy wrote:
Tue Sep 04, 2018 6:49 pm
Did the step-down providing 5V survive that ?
Nope that's blown too.
Was the power connected through the microUSB connector or via the GPIO connector?
It's connected via the microUSB
In either case it might be difficult to determine cause and effect of the two faults, but a step-down fault that applied too much voltage through the microUSB should have been "safe" for the Pi, because the protection zener diode would work long enough the open the polyfuse. Worst case the protection diode itself fails, but can be replaced. In this case it looks like catastrophic failure of both diode and polyfuse.
Yes and also there's another motherboard board drawing power from the same source as mine, and that's not got affected. I'm unable to arrive at a conclusion as to what might have caused this and fried the pi.

pfletch101
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Re: Raspberry Pi Power Source

Tue Sep 04, 2018 7:58 pm

nachiketh wrote:
Tue Sep 04, 2018 7:38 pm
Yes and also there's another motherboard board drawing power from the same source as mine, and that's not got affected. I'm unable to arrive at a conclusion as to what might have caused this and fried the pi.
Is the 'another motherboard' also a Pi? If not, is there anything on or connected to the other motherboard that could have produce a power spike? You should also, perhaps, consider the possibility (admittedly not prima facie very likely) that the Pi failed catastrophically for some reason unconnected to bad power, taking the step-down with it.

nachiketh
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Re: Raspberry Pi Power Source

Wed Sep 05, 2018 4:56 am

pfletch101 wrote:
Tue Sep 04, 2018 7:58 pm
nachiketh wrote:
Tue Sep 04, 2018 7:38 pm
Yes and also there's another motherboard board drawing power from the same source as mine, and that's not got affected. I'm unable to arrive at a conclusion as to what might have caused this and fried the pi.
Is the 'another motherboard' also a Pi?
The other motherboard is an Intel base board
If not, is there anything on or connected to the other motherboard that could have produce a power spike?
The only input source to the DC-DC buck converter is the SMPS, I dont think the SMPS by design allows a current in reverse, correct me if i'm wrong :?
You should also, perhaps, consider the possibility (admittedly not prima facie very likely) that the Pi failed catastrophically for some reason unconnected to bad power, taking the step-down with it.
I will have to test it for a longer duration to narrow down the possibilities.

Brandon92
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Re: Raspberry Pi Power Source

Wed Sep 05, 2018 5:46 am

Can you tell us what the 27v power supply is feeding. If I read it correctly it also power the other motherboard directly? And are there any kind of inductive (aka motor) or ?

I believe that something happends to the 27v power rail. Because a 5v 3a doesn't have enough power to blow a tvs diode like that. And the fuse is before the tvs. And if there is some short of "spike behind" the Rpi the tvs is one of the last component that will see it. And if the tvs dies from that, a 15w power supply doesn't blow up the poly fuse like that. Also, a I think a cheap 5v power supply has a over current protection?

However when there is some spike on the 27v line. A cheap power supply, I think, will not have some short of input filtering and that voltage spike will go to the buck converter. And will kill the (high side) MOSFET. When this happens the MOSFET is almost always a short. So, the input voltage is now present at the output. And a 27v power supply has enough power to blow up the tvs diode and the poly fuse, like there are event there. And if there are any sensitive devices (sd card) on the Rpi, there are also gone. And I can speak this out of experience, with a other product. A 24v @10A will do fun stuff to a 5v input :?

However, we can speculate about what happens for a while. But, a block diagram of how all the pieces are connected could be very helpful for this.

nachiketh
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Joined: Wed Sep 25, 2013 4:54 pm

Re: Raspberry Pi Power Source

Wed Sep 05, 2018 5:31 pm

Brandon92 wrote:
Wed Sep 05, 2018 5:46 am
Can you tell us what the 27v power supply is feeding. If I read it correctly it also power the other motherboard directly? And are there any kind of inductive (aka motor) or ?
Ok so here are the output rating of the SMPS:
Rated voltage Vout DC 24 V
Total tolerance, static ± 3 %
Static mains compensation, approx. 0.5 %
Static load balancing, approx. 1 %
Rated current value Iout rated 20 A
Current range 0 ... 20 A
Supplied active power typical 480 W
Brandon92 wrote:
Wed Sep 05, 2018 5:46 am
A cheap power supply, I think, will not have some short of input filtering and that voltage spike will go to the buck converter. And will kill the (high side) MOSFET. When this happens the MOSFET is almost always a short
My knowledge in this area is limited, but dont you think then the whole purpose of a buck converter is lost :? how do I prevent the full 24V to go through

Brandon92
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Re: Raspberry Pi Power Source

Wed Sep 05, 2018 7:51 pm

Don't get me wrong. But, a buck converter is still a good product. To convert high voltage to a lower voltage. But you need to find a good one.

I don't know exactly what you want and for what for kind of application, but take a look at: I think you want something like the last one. And here you could find more from that brand. But, there are also other good brands.

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