Abusing a poor power supply I got cheaply on amazon... but is it so innocent?

Am I wrong to abuse my power supply? Will it get revenge?Or does it deserve it for the false claims?

  • It will not get revenge and continue to deal with the shorts.

    Votes: 0 0.0%
  • It is innocent! Stop abusing it!

    Votes: 0 0.0%

  • Total voters
    2

Thread Starter

-live wire-

Joined Dec 22, 2017
956
A few weeks ago I got this power supply off of amazon. I needed one that was moderately powerful and cheap for a robotics project. It actually did work well enough.
https://www.amazon.com/KNACRO-Switc...1525554774&sr=8-1&keywords=6v+6a+power+supply
Long story short:D, one of my friends' teenage child shorted it out and melted a hole through the breadboard used to control the servos. Teens. :mad:

Thankfully not too much was ruined, but this claim here is clearly BS:
"With overload overvoltage overheating short circuit protection, multi-filter with magnetic interference."
"overcurrent protection"?!? As in when the burning wire turns into a fuse? Or "overcurrent protection if your breakers are working :)".
"Overheating"? Well, it didn't explode. So that's a plus.
"multifilter with magnetic interference"? Umm.... what are they talking about? And since when was susceptibility to EMI a good thing? o_O
"overvoltage"? I guess you'll notice when you load blows up. But I think they mean it is not a direct wiring from mains to your output. Actually though, it does seem to be around the rated voltage.

"Low operating temperature and long service life." Assuming you don't use it, of course.

"Good insulation performance, high resistance to electrical strength." WTF? I guess it didn't start arcing.

Miraculously it still seems to work fine. It supplies many amps, much greater than 6, when shorted. So I decided to have some fun. I used it to charge my 2.7V 500F supercapacitors, which were just sitting on the shelf. I didn't use any resistors. It kind of acted like a CC power supply. It charged 3 in series (166F) from 0V to 6V within 30 seconds. So I'd say it works pretty well. One interesting thing I noticed is a faint 60Hz hum when there is overcurrent.

So am I wrong to abuse my power supply like that? Or does it deserve it for all the BS claims? And will it get it's revenge by failing terribly? And thoughts in general?
 

Hymie

Joined Mar 30, 2018
1,090
A few weeks ago I got this power supply off of amazon. I needed one that was moderately powerful and cheap for a robotics project. It actually did work well enough.
https://www.amazon.com/KNACRO-Switc...1525554774&sr=8-1&keywords=6v+6a+power+supply
Long story short:D, one of my friends' teenage child shorted it out and melted a hole through the breadboard used to control the servos. Teens. :mad:

Thankfully not too much was ruined, but this claim here is clearly BS:
"With overload overvoltage overheating short circuit protection, multi-filter with magnetic interference."
"overcurrent protection"?!? As in when the burning wire turns into a fuse? Or "overcurrent protection if your breakers are working :)".
"Overheating"? Well, it didn't explode. So that's a plus.
"multifilter with magnetic interference"? Umm.... what are they talking about? And since when was susceptibility to EMI a good thing? o_O
"overvoltage"? I guess you'll notice when you load blows up. But I think they mean it is not a direct wiring from mains to your output. Actually though, it does seem to be around the rated voltage.

"Low operating temperature and long service life." Assuming you don't use it, of course.

"Good insulation performance, high resistance to electrical strength." WTF? I guess it didn't start arcing.

Miraculously it still seems to work fine. It supplies many amps, much greater than 6, when shorted. So I decided to have some fun. I used it to charge my 2.7V 500F supercapacitors, which were just sitting on the shelf. I didn't use any resistors. It kind of acted like a CC power supply. It charged 3 in series (166F) from 0V to 6V within 30 seconds. So I'd say it works pretty well. One interesting thing I noticed is a faint 60Hz hum when there is overcurrent.

So am I wrong to abuse my power supply like that? Or does it deserve it for all the BS claims? And will it get it's revenge by failing terribly? And thoughts in general?
Based on your post, you are complaining that under short circuit/overload of the output of the power supply resulted in an excessive current flow. But following removal of the fault the power supply functions correctly; so I would say unless the specification includes a maximum output short circuit current – you have nothing to complain about.
 

be80be

Joined Jul 5, 2008
2,069
That is really not for sure known you may of turned it off before over current kicked in.

I've seen this happen I have a 2 amp supply I use it doesn't cutout till about 3.5 amps.

The little jumper wires I use melted off the wire at 2 amps.

I hooked a motor to it without the jumpers it shut down at 3.5 amps turned it off unhooked the motor supply still works like new.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
956
I guess going into CC is kind of overcurrent protection, but it is still certainly a hazard. So I connected it in parallel to my supercapacitor bank and got many 10s of amps. I need to actually get an amp clamp, but it was clear a lot of current was flowing. And the best thing is the supercaps are always being charged, so if I take a break, they charge back up.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
956
Many tens of amps through those skinny wires? I think your meter is telling you fibbs :)
I am not using my meter! That would instantly blow a fuse! And those wires are about 12-14 AWG. That means 2ish milliohms per foot. The real problem would be ESR. The total resistance, including ESR, is probably about 50-100 milliohms. This means 6V/.05O=120A. maybe 60A due to stuff heating up and more ESR than I thought.
 
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