Power supply fail head's up

[Miguel1983]

Hi all,

i've recently had some issues with my power supply's.

I use two regulated 13,8V 10A (voltcraft FSP-11312 ) power supply's on my main imaging rig, one for the mount and one that powers all the rest via a pocket powerbox (PPB) from Pegasus astro.

The power supply's are placed under the raised platform of my obs and connected to two cigarette lighter style sockets next to my pier, so i never see them, i do have a switch at my desk to turn of the power when not in use.

So 2 weeks ago i powered up my gear and i heard a weird noise, went to investigate in the cold room of the obs and i immediately smelled a burnt scent, crap !, my EQDIR cable was literally melting, i pulled out the power cords and found my EQDIR RJ45 socket was stuck in the socket of my EQ6R, the plastic had molten. 

When pulling it out i damaged the RJ45 socket on the motherboard of the EQ6R, luckily my neighbor repairs PCB's for a living so my EQDIR cable and motherboard were fixed within a few days, the conclusion was the the EQDIR cable RJ45 socket was probably faulty and caused a short circuit.

 

Happy that everything was fixed i reassembled my rig and powered up... another weird noise ! 

This time the burnt smell came from my ASI1600 😱 

 

After some investigation i discovered that one of the power supply's was giving 28.6V in stead of 13.8V , that's what caused the damage on my EQ6R and after reassembly i probably switched the power cables causing an over-voltage on the PPB, luckily only the ASI1600 suffered damage.

Although the PPB has a protection against over voltage, it clearly does not cut the power outputs fast enough to prevent damage.

Once again my neighbor was able to fix my camera and he checked the power supply and suggested never to use those kind of power supply's again as there is no sufficient protection built in, so he provided me with two new power supply's. (wallet next to it for size)

 

So to all, please be aware of this, this happend to my with a one year old power supply, i'm lucky to have a neighbor that can fix these kind of electronic problems, i'm sure i would have lost lots of time and effort dealing with these issues trough customer service from SW an ZWO.

Clear skies !

 

 

 

 

Edited September 7, 2020 by Miguel1983

[Robindonne]

Even while i dont have very expensive equipment, this is what im afraid of happening every time i plug in a powersupply.   Not traumatized orso but having read so much issues and fried parts.   Almost daily/weekly.   I did last week a check on one of my power supplies.  Steady 12 volts.  But a peak of 18/19 volt at the start.   We should protect more of our equipment against these fluctuations.   Its probably cheaper then being late an having to replace mounts or cameras

Edited June 21, 2020 by Robindonne

[Davey-T]

I prefer to use 40ah Tracer LifePo battery for ancillaries and two smaller ones for mount and laptop, no chance of overvoltage.

Dave

[Dr_Ju_ju]

With power supplies, the old adage "You get what you pay for" holds very true.

If you want peace of mind, then buy a respectable brand, good quality supply, with the safety features built in and not just given lip service too, but it won't be cheap.... 

[Skipper Billy]

I went back to using leisure batteries for this reason - smooth, clean, quiet reliable cheap power. 

[saac]

I can see a trend here with what Miguel has experienced.  In my case the power supply was a Maplin unit , but I'm sure these are all cones of each other using same/similar components.  I ended up modding the supply by installing a programmable voltage controller with over-volt protection.  So far all has been good but it definitely looks like these units are prone to failure. 

Jim 

 

[StuartJPP]

If people knew how Switch Mode Power Supplies operate then they'd think twice about using them.

Think of a Switch Mode Power Supply as a nest full of angry wasps buzzing away, until something (anything) upsets them.

I am of course being a bit facetious, and allegedly they can be designed properly.

On the flip side, a freshly charged 12V leisure battery can deliver at most about 14V, give or take. It can deliver a lot of current, so it can melt wires and set fire to things if wired incorrectly, but it will never deliver more voltage than chemically possible.

Now if only the manufacturers would put an "idiot" diode in line with the circuit board or better yet a FET and derate the component operating voltages/currents then it would be practically impossible to blow a board up by plugging it in, except for actual component failure on that board.

[Robindonne]

2 hours ago, Dr_Ju_ju said:

With power supplies, the old adage "You get what you pay for" holds very true.

If you want peace of mind, then buy a respectable brand, good quality supply, with the safety features built in and not just given lip service too, but it won't be cheap.... 

What is a respectable brand?   I googled a lot in out country for 12v power supplies.  Its like they’re all the same unknown brand bricks.  The only thing i thought of was buying a laptop ps to be sure its a “brand”.  And because most of them deliver good amps but high voltages i thought using a stepdown converter.  But while mentioning and asking in various threads, non of the reactions are telling me to go this way.  
“Nevada” powersupplies seems a common choosen brand but i bet nobody ever heard of that brand.  Its just that a big shop offers it, otherwise it just wasnt sold and used this much.   
if you can help me with choosing respectable brands?  Thx in advance 

[Robindonne]

30 minutes ago, StuartJPP said:

On the flip side, a freshly charged 12V leisure battery can deliver at most about 14V

Its probably the safest route to power your stuff.  But do you know any with a bypass function?   Or is it then The same Risk of being open to overvoltage.   If a brand sells a battery pack with a bypass function its definitely a good choise for an all-in-one power solution

Edited June 21, 2020 by Robindonne

[Dr_Ju_ju]

A couple of reputable brands Meanwell, TDK-Lambda, PowerPax, Omron, Yuasa ..... and there are loads more a good\reputable suppliers would include the likes of RS-Components, Farnell etc...

this is a link to one that Farnell sell, note that its designed for medical usage, therefore MUST comply with all safety specs (sorry about length of link)... https://uk.farnell.com/mascot/2026-9726-12v/power-supply-ac-dc-medical-13/dp/1183935?pf=113225634&st=12v+power+supply&krypto=WblLZvI1hmq24vQ%2Fc1ALh2i9PrTCuEWkeTd%2BaNArEcjhNKWVBZDPJFN70u78oEfNmasxcyaqeZK6lpR%2FN5UDJ3bJtRAzs0MYSghs5xP2kCQcJ%2BN%2BzL89ijYqdDiI3X63ZD1JJQbqm4SKQrEB6OJkkxmHqIjce9gCS0J0T07Kqcq4Iv9M2DvDtJpNvHn7RMtUjNgd%2FGiemK%2BEu2cyPufIm6LOsqIKfdNItq6UThUn3hLcsoysPmWdNzw8KW5uGhVqwAB1KFTTcVUtXUYnDElRrV3hP9v%2BM1MirIoZzwN15iTzfyFRxtksKWg3exO%2BfpTjCl45hNyoLJcQ8REAdvvE%2F1WBtvVKagiHTfn3%2BZs0oz15Vzp5ohRf8qSIi37y3vUEu3nUVm09rx7kuP6KnE%2BIxxBXFWN6KloYtve6ee5p5w4mwy4bwtg0yNqRYf%2BciVY5ildhktZ3Q04tlWMdQ74b1v%2Bz1PZqNOcF4gbBNHVSoD25WGQ2q8aBdbrWZEIN6w5G7dhzR4ZBxLF3ayVUeFHCZww5AMP%2FRs9ibeXKNQBHLEDZMCkssrpgGfxvuu82QXmdLD0Y4Brq8zYlcJgN0fekqojVCqIvRr%2F%2BLD83LRcng80%2FWmDISx4ZTs3SSQD8YpKgddHlCSTz17CO8nRb1I6Lo1Gq2n7nZJYVA413bVYqWKs4vPXMjapDRjz6vIdHsUzC4hA1T%2FkB6DjFi%2FSGDomLK0MlicEjRJcXGj9gotF4QyedKO94o5l6WZhWgzFFdYcTkyeCJLau7x1uSgxxFSsri5XX7Y0t3uDhs5TJwIFLR6mRNHHvF2yx5Nvkon%2BE4Ru8zZGagWhQEBkU157m3hwTGhdSrGppJK2p6dK6MJy1SgtKM6m8GcXpLfskIzhZBnM8nn7D5W3aPEPQNfCYOPxPESRoiLXsZIrAPwmHbueesUXv5cRFmHAKDQ3mzH%2B5WKcEyyH6ERDa%2Bp%2BVVlkbYPCTmQ%3D%3D 

[Robindonne]

2 hours ago, Dr_Ju_ju said:

A couple of reputable brands Meanwell, TDK-Lambda, PowerPax, Omron, Yuasa ..... and there are loads more a good\reputable suppliers would include the likes of RS-Components, Farnell etc...

Really big thx.  Wouldnt have come up with any of the brands.  Dont know why its. So hard here in Holland to find These results when searching for powersupplies.   

[malc-c]

Whilst expensive, you can't beat genuine meanwell power supplies.  I've been using a 48v Meanwell to power my DIY LED rig for the reef tank which has been running 24/7/365 for the past 8 years and not so much as a blip.

Sounds like you have picked a good person for a neighbour... saving you a fortune on new motor boards and cameras

 

[david_taurus83]

Am I right in thinking this issue is not possible with a transformer type linear power supply?

[Dr_Ju_ju]

Nope, transformer supplies can go high voltage (failure in transformer), and linear supplies have their own suite of problems (weight being the least of them), and must also be designed & built to high standards.....

For out in the field\star parties, I use a linear bench power supply  0-30v \ 10A,  that used to be sold by Maplins (now defunct) at very reasonable cost.   

[Robindonne]

9 hours ago, Dr_Ju_ju said:

Nope, transformer supplies can go high voltage (failure in transformer), and linear supplies have their own suite of problems (weight being the least of them), and must also be designed & built to high standards.....

For out in the field\star parties, I use a linear bench power supply  0-30v \ 10A,  that used to be sold by Maplins (now defunct) at very reasonable cost.   

I found some meanwell ps’s.   Bought 2 12v 6.6 amps. Indeed went for the medical ones.  Like €30,- each.   Looks all ok. 
Really thought this powerbrickmarket was filled with clones who fail now and then. Although while googling for meanwell brought me at first at the well famous aliexpress, they were also sold by conrad and prices were the same(maybe even better when no import-tax at the conrads ones).  Thx again for helping me out a bit

[symmetal]

19 hours ago, david_taurus83 said:

Am I right in thinking this issue is not possible with a transformer type linear power supply?

The OPs power supplies are linear supplies using large transformers. The transformer has to supply sufficient voltage such that at maximum current draw the minimum voltage on the unregulated dc reservoir capacitors doesn't fall below the regulated output voltage plus the dropout voltage of the regulator stage, so an off load unregulated dc of 28V is fairly typical.

On a basic regulated DC supply the only thing keeping the unregulated DC from the output are the  transistors mounted on the large heat sinks on rear of the power supply. These transistors, along with their control circuitry, form a series regulator whose effective resistance varies depending on the current drawn to maintain the constant output voltage. These transistors dissipate the excess power due to the difference between the unregulated voltage and the stable output voltage. If one of them goes short circuit, often due to running too hot for too long, then the scenario experienced by the OP occurs.

More expensive power supplies will incorporate over-voltage protection, current limiting etc. but there's no guarantee that the protection circuitry won't fail too.

I too use Meanwell SMPSUs from Farnell. The original 100W versions I bought had been bench tested at full current by the manufacturer for 100 hours prior to sale and were about £45 each. The latest ones I bought were identical but hadn't been bench tested for 100 hours, and were £20 cheaper. I've never had any issues with them.

Alan

[Corncrake]

I've not yet read all the posts, but has anyone said about this method of protection :

You dont need a very big (high capacity) 12v battery leisure or otherwise to give overvolt protection.

A smaller 12v battery can be supplied by the psu into one clamp on the +terminal.
a second wire (screw, clamp, whatever) is then attached to the  +ve terminal BUT NOT TO the psu point of attachment****.

That way if the psu tries to go high it will be clamped by the battery, such that the psu fuse (if any) or its internals will melt as the battery draws amps attempting to reach it.
The output wire from the battery to your equipment will not go higher than the battery.

**** if you fix the equipment wire to the psu wire and then that combo to the battery, think about it falling away / being dislodged / from the battery. The equipment will then only be attached to the psu, which may, in time, then go high while you didnt notice the detachment !

Anyone want a diag ?

 

[Robindonne]

28 minutes ago, Corncrake said:

I've not yet read all the posts, but has anyone said about this method of protection :

You dont need a very big (high capacity) 12v battery leisure or otherwise to give overvolt protection.

A smaller 12v battery can be supplied by the psu into one clamp on the +terminal.
a second wire (screw, clamp, whatever) is then attached to the  +ve terminal BUT NOT TO the psu point of attachment****.

That way if the psu tries to go high it will be clamped by the battery, such that the psu fuse (if any) or its internals will melt as the battery draws amps attempting to reach it.
The output wire from the battery to your equipment will not go higher than the battery.

**** if you fix the equipment wire to the psu wire and then that combo to the battery, think about it falling away / being dislodged / from the battery. The equipment will then only be attached to the psu, which may, in time, then go high while you didnt notice the detachment !

Anyone want a diag ?

 

Yes.  Please.  A diagram would help a lot. Thx

[Corncrake]

44 minutes ago, Robindonne said:

Yes.  Please.  A diagram would help a lot. Thx

a fuse can be added in the good wire, remember that fuses should not be used to protect electronics, electronics will usually fail before a fuse melts !

Fuses are meant to protect surroundings from fire, molten copper, smoking plastic, etc.

Electronic safeguards are needed to protect electronics, then you have a case of who guards the guardian it can get expensive to ensure all failure modes.

Edited June 22, 2020 by Corncrake

[Robindonne]

14 hours ago, Corncrake said:

a fuse can be added in the good wire, remember that fuses should not be used to protect electronics, electronics will usually fail before a fuse melts !

Fuses are meant to protect surroundings from fire, molten copper, smoking plastic, etc.

Electronic safeguards are needed to protect electronics, then you have a case of who guards the guardian it can get expensive to ensure all failure modes.

And what types of batteries do you suggest to make this setup with?   Im not really fan of to big things to move around every night.  Except this setup, because of the similarity with a batterypack that has a bypass function.   If these were available, and deliver enough amps i would choose one.  Just for the reason to never pass the max 12v but also to be able to drive outside and not worrying about power.  At least if this method keeps the battery fully charged.  

Edited June 23, 2020 by Robindonne

[pete_l]

11 hours ago, Corncrake said:

a fuse can be added in the good wire, remember that fuses should not be used to protect electronics, electronics will usually fail before a fuse melts !

Fuses are meant to protect surroundings from fire, molten copper, smoking plastic, etc.

You can add a fuse and a "crowbar" circuit after the PSU (switched or linear) to protect against over-voltage conditions.

Basically this comprises a zener diode to act as an over-voltage sensor and an SCR to short-circuit the output voltage. That short will cause the output fuse to blow. Since the SCR will switch on very quickly, it will protect your equipment for the milliseconds that the fuse takes to cut the power.

[Corncrake]

1 hour ago, pete_l said:

Basically this comprises a zener diode to act as an over-voltage sensor and an SCR to short-circuit

Yes quite so, that is what I meant by electronics to protect electronics ! But it is not easily implemented by those who* dont know what a zenner is and how to rate it so that it does not fail when called upon ! You dont even need the SCR if you choose a big fat zenner.

* and those who will expect it already built in to their higher cost PSU.

The battery crowbar method is not perfect in all circumstances but is an extra easily implemented precaution for those using less than perfect PSUs
The battery is not required to fulfill the load watt-hours, it is just there to cause an over-current event if the PSU tries to go high voltage.

Edited June 23, 2020 by Corncrake

[Guest]

Don't know if this may help, especially if you're handy with a soldering iron...

https://pa0fri.home.xs4all.nl/Diversen/EP925/ep925eng.htm

[wxsatuser]

On 21/06/2020 at 14:14, Robindonne said:

What is a respectable brand?   I googled a lot in out country for 12v power supplies.  Its like they’re all the same unknown brand bricks.  The only thing i thought of was buying a laptop ps to be sure its a “brand”.  And because most of them deliver good amps but high voltages i thought using a stepdown converter.  But while mentioning and asking in various threads, non of the reactions are telling me to go this way.  
“Nevada” powersupplies seems a common choosen brand but i bet nobody ever heard of that brand.  Its just that a big shop offers it, otherwise it just wasnt sold and used this much.   
if you can help me with choosing respectable brands?  Thx in advance 

I have no problem using Nevada PSUs, Mike is well respected on the stuff he sells.

I recently bought two expensive transcievers and with them came two free supplies.
This type in fact
https://www.nevadaradio.co.uk/product/nevada-psw-30/

One supply powers the two transcievers that are worth around 3grand and the other powers
a geostationary satellite transciever plus an expensive 2.4ghz upconverter worth over 2grand.

[Robindonne]

31 minutes ago, wxsatuser said:

I have no problem using Nevada PSUs, Mike is well respected on the stuff he sells.

I recently bought two expensive transcievers and with them came two free supplies.
This type in fact
https://www.nevadaradio.co.uk/product/nevada-psw-30/

One supply powers the two transcievers that are worth around 3grand and the other powers
a geostationary satellite transciever plus an expensive 2.4ghz upconverter worth over 2grand.

Im sure its not a bad brand at all.  I guess its used a lot among hobbyists in this hobby because its implemented through dealers though.  So there must be more out there that will work good.
 For me, and i guess for more, its just a too bulky module to go outside with.  If it were a batterypack It would be more justified To walk around with a medium sized energystation. I hoped to end up with some lightweight and small (attached to the mount legs) powersupply.

 I assume if small boxes/cases with just the protection were available, small as in easy to place between powersupply and the device itself, they would be bought with, in this hobby, the mount.  
Two days ago some here convinced me to buy new switched psu’s.  Ended Up buying Two from meanwell. The costs were low and will have plenty of amps to Feed my devices.   The one thing that keeps missing is that overvoltage protection😬.   The description from another forum member: a switched psu is like A nest of angry wasps that are eager to escape the housing of the psu through the cable stayed in my head.   
maybe i have to go see a doctor for this trauma! 
 

im very open for diy solutions if its good to do for an amateur who can do small soldering. I think all those who have smelled a burned board will say the same.  Its an invisible and unpredictable risk when you rely on a switched psu