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12v power problem w/ mount, PC

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#1 GoldSpider

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Posted 29 March 2020 - 07:08 PM

I'm looking for some help from people more electronics-inclined than myself.

 

I have my mount, ZWO cameras, and mini PC (which runs off 12v) connected to a rigrunner, which is powered by a 30-amp 12v power supply.  The mount and cameras are connected to the PC over USB.  There are no 12v cable runs longer than 6 feet.

 

I power on the PC and cameras first to do polar alignment, and then power on the mount.  When I power on the mount, the PC shuts off.  It powers back on without a problem, but I don't like that this is happening and would like to get to the bottom of it.

 

Any ideas?

 

Thanks!



#2 Aaron Small

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Posted 29 March 2020 - 07:29 PM

Sounds almost like just enough of a surge where the voltage drops just enough to power off the PC.  Normally I would think a mount wouldn't have a draw like that though.    What I have seen is a capacitor or some other power storage device (battery) to maintain the voltage for a second or two while other things are turned on.

 

You probably want to throw out some more specs on your rig as your description is pretty generic.  What is your power supply and mini-PC.  Those specs could be the key.  

 

My 12V supply is a marine cycle battery so it can take the quick draw.



#3 scopewizard

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Posted 29 March 2020 - 07:29 PM

Mini pc are very sensitive to voltage below 12vdc. If it drops to 11.8 it may shutdown. You can use voltages higher but first check if it has tolerance above 12 vdc before trying this out. I operate mine with 13 volts without problems. I have seen some with max voltage of 20 vdc. When you turn your mount on, it might have a quick drop due to demand which could be enough to create a shutdown.



#4 GoldSpider

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Posted 29 March 2020 - 07:37 PM

Sounds almost like just enough of a surge where the voltage drops just enough to power off the PC.  Normally I would think a mount wouldn't have a draw like that though.    What I have seen is a capacitor or some other power storage device (battery) to maintain the voltage for a second or two while other things are turned on.

 

You probably want to throw out some more specs on your rig as your description is pretty generic.  What is your power supply and mini-PC.  Those specs could be the key.  

 

My 12V supply is a marine cycle battery so it can take the quick draw.

 

I'll provide as much detail as I can; I'm not terribly fluent in the language of electronics!

 

Power Supply:

https://www.amazon.c...y/dp/B06XY8P44G

 

Mini PC:

https://www.amazon.c.../dp/B07WWDBM83/

 

The AC adapter that came with the PC provides 3A max.  In general the system sips power, but I too suspect that the mount is drawing an unusual amount of power when it starts up.  I think the wire I have running to the mount might be a bit thin (only 24AWG but the mount is specced to draw 2A max) but I'm not sure if that might be a contributing factor.  Short 18AWG run from rigrunner to the mini PC.

 

Happy to provide any additional details you need.



#5 GoldSpider

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Posted 29 March 2020 - 07:38 PM

Mini pc are very sensitive to voltage below 12vdc. If it drops to 11.8 it may shutdown. You can use voltages higher but first check if it has tolerance above 12 vdc before trying this out. I operate mine with 13 volts without problems. I have seen some with max voltage of 20 vdc. When you turn your mount on, it might have a quick drop due to demand which could be enough to create a shutdown.

I have an inline ammeter/voltmeter I plan on putting between the rigrunner and mini PC to see if the voltage is indeed dropping when I power on the mount. 



#6 Michael Covington

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Posted 29 March 2020 - 08:20 PM

Is this some strange problem with unequal grounds?   The mini PC is attached to other things through the USB cable, and they are all on the same power supply.  Is USB ground connected to the mini PC's power supply ground?  Or is the PC supposed to be separately powered?  



#7 GoldSpider

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Posted 29 March 2020 - 08:21 PM

Is this some strange problem with unequal grounds?   The mini PC is attached to other things through the USB cable, and they are all on the same power supply.  Is USB ground connected to the mini PC's power supply ground?  Or is the PC supposed to be separately powered?  

Mini PC is separately powered.  I've experienced this a few times in the field, and while I'm cooped up for a few weeks I can try a few more combinations; see what it does with the camera disconnected, for example.

 

Edit:  To clarify, the mini PC is powered separately from USB, but all devices are on the same 12v power supply.


Edited by GoldSpider, 30 March 2020 - 06:53 AM.

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#8 Aaron Small

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Posted 30 March 2020 - 06:54 AM

Dave,

 

Saw this user review of your PSU on Amazon:

 

Reviewed in the United States on July 7, 2018

I bought this item to power an amplifier that draws 15 amps. It will not power up the amp using the Anderson power poles but powers it up just fine using the binding posts on the rear.
3 people found this helpful

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See all reviews from the United States

 

You may want to check those Anderson poles on the front with your ammeter/voltmeter.

 

Scopewizard described (better) the issue I was thinking of with the PC dropping out.



#9 macdonjh

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Posted 30 March 2020 - 07:23 AM

GoldSpider,

 

I know you're looking for an actual solution rather than a work-around, but could you unplug your PC and let it run on its internal battery while you power your mount up?  Then plug your PC back in?

 

Perhaps the actual solution is a beefier power supply for your PC; one with better regulation to prevent the voltage drop when you turn your mount on?



#10 Noah4x4

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Posted 30 March 2020 - 07:25 AM

I'm looking for some help from people more electronics-inclined than myself.

 

I have my mount, ZWO cameras, and mini PC (which runs off 12v) connected to a rigrunner, which is powered by a 30-amp 12v power supply.  The mount and cameras are connected to the PC over USB.  There are no 12v cable runs longer than 6 feet.

 

I power on the PC and cameras first to do polar alignment, and then power on the mount.  When I power on the mount, the PC shuts off.  It powers back on without a problem, but I don't like that this is happening and would like to get to the bottom of it.

 

Any ideas?

 

Thanks!

This is where a lot more equipment information could be revealing.

 

For example, a lower specification Intel NUC will run on "12 - 19 volts + or - 10%". If running on a "12v" supply, it doesn't take much of a voltage drop to witness a cut off. I had a load of problems with cheap Asian batteries that start at 12v but soon deplete to as little as 9.6V.

 

Whilst most devices will only draw the amperage they require, if too great, some will cut off. I tried running my camera (seeks 2A, Focuser 1A, NUC 3A) using a 12v 10 Amp AC/DC supply and my NUC didn't like that. I now use two 5A supplies and all is fine.  It could be 30A is just too much.

 

EDIT

Just read note 2.2.4.3 of my Intel NUC specification. This states that the maximum current rating is 10 Amp. You need to sort out power if your mini PC is similar. 


Edited by Noah4x4, 30 March 2020 - 07:33 AM.


#11 GoldSpider

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Posted 30 March 2020 - 10:08 AM

GoldSpider,

 

I know you're looking for an actual solution rather than a work-around, but could you unplug your PC and let it run on its internal battery while you power your mount up?  Then plug your PC back in?

It's not like a laptop that has a battery; it needs an external power source.

 

 

 

Just read note 2.2.4.3 of my Intel NUC specification. This states that the maximum current rating is 10 Amp. You need to sort out power if your mini PC is similar. 

The wall wart adapter that comes with the PC specifies a maximum 3 amp at 12v.  The power supply is more than up to the task at supplying enough current for the rig.  I think the key here is getting the ammeter/voltmeter to see if there is a spike happening at the mount end, or a drop at the PC end.

 

The more I'm reading, the more I suspect a voltage problem at the PC end.  I recall the power LED on the unit is normally blue when it is on, but recall seeing it turn red before powering off.  According to the Minix forums, this (on other models at least) indicates a voltage problem.



#12 Noah4x4

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Posted 30 March 2020 - 12:31 PM

We need to be careful not to confuse 30 Continuous Amps and 30 Amp-hours. The power device mentioned is belting out 25 Amps continuous and 30 Amps peak. A UK house circuit is a maximum of 30 Amps. Most quite powerful UK devices (like vacuum cleaners)  are rated a maximum of 5 to 13 amps.This is a monster of a power supply, albeit low voltage.

 

Convention  says that a device will only draw what amps it needs, so a 12V 30 Amp continuous  supply, will, in theory, support multiple  12v x 3A devices.  However, some devices will cut out if voltage or amps (hence volts x amps = watts) are too high or low. I discovered the hard way that an Intel NUC (12v/5A or 19v 3A) won't work with a 12v 10A supply. It sparked as I plugged in the adapter,  but fortunately no damage! I suspect a Minix has similar limits and should be powered by 12v 3A and certainly no more than 5A.



#13 NoDarkSkies

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Posted 30 March 2020 - 12:56 PM

I would just use a Powered USB 3.0/1 Hub and only one USB port on the Mini for the Mount and Camera Stuff.

Maybe a Non LED or RGB KB and Mouse on the Mini as well.


Edited by NoDarkSkies, 30 March 2020 - 12:57 PM.


#14 GoldSpider

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Posted 30 March 2020 - 02:17 PM

I would just use a Powered USB 3.0/1 Hub and only one USB port on the Mini for the Mount and Camera Stuff.

Maybe a Non LED or RGB KB and Mouse on the Mini as well.

I do have a powered USB hub I can add into the troubleshooting.  The rig is headless (I remote desktop into it from any convenient device) so it doesn't need anything other than cameras, mount, and (later) focuser motor connected via USB.  If the system behaves differently from a USB hub, I'd be curious to know why.



#15 carolinaskies

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Posted 30 March 2020 - 03:25 PM

A picture of the power unit and how you seperately connect to it via the mini comp and USB Hub would be helpful.  

The front panel of the PS has a V/A switch so you can actually look at that for a quick look at what is happening as you power on the devices.  

Many mounts boot up typically around 1.5-2A and nominally run ~<1A driving the RA and only punch beyond that during slewing.   

If the computer is dropping during mount power up it's because of the way in which you boot off a single point of power. 

Some devices don't care about even minor changes in power supplied, but to protect sensitive electronics computers are typically designed with sensitivity to power fluctuations and the safe course is to cut power vs risk damage from a commesurate spike in either direction.  Even your USB hub has protection built in out the USB lines for this to prevent spikes.

I think it's pretty clear this is routed in your startup sequence as the mini comp acts normal until you boot the mount and then powers fine upon reboot.
So whatever drop is occuring is enough to trouble the mini comp to go out. 

This is why PS for computers use clean power signals, to eliminate those spikes which do happen regularly in AC systems and it allows the PS to provide the constant 12V and amps necessary.  This is why having multiple outputs from a power unit is helpful because they are isolated internal in the unit and don't allow the feedback to affect other devices.  

I don't know if your unit seperates the front ridgerunner and rear screw power connectors, but you might be able to connect seperately(if your not already doing this in your current setup) and test to see if the issue still happens.   Typically it's best to seperately power the mount from all other accessory devices that dont' already run through the mount's system. 

We do this on battery systems of course to keep the mount running even if we lose other non-tracking devices which can be brought back up with seperate sources without having to go through a whole realignment routine.  

You may be able to add a type of surge protector to the computer power line to stop this.  Contact your local electronics supply warehouse and talk with a technician who can likely point you to the best device.  





 



#16 GoldSpider

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Posted 30 March 2020 - 05:17 PM

I don't know if your unit seperates the front ridgerunner and rear screw power connectors, but you might be able to connect seperately(if your not already doing this in your current setup) and test to see if the issue still happens.   Typically it's best to seperately power the mount from all other accessory devices that dont' already run through the mount's system. 

I'll assemble the whole system inside and post some pictures.

 

Regarding this part of your post, perhaps you can guess as to whether or not the two separate powerpole outputs are actually separate outputs.  Easiest thing to do, of course, is to test this.

 

Link to photo of unit showing powerpole connectors

 

Edit:  I could always just use the wall-wart that came with the PC since the 12v power supply is plugged in to AC anyway if I wanted to make this easy on myself, but where's the fun in that?


Edited by GoldSpider, 30 March 2020 - 05:39 PM.


#17 scopewizard

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Posted 30 March 2020 - 05:49 PM

The simple way to define the problem is to start at the source. Get a 12 vdc car battery and attach the wire from your power supply to the battery. Turn the min-pc on and mount later and see if it fails. If it does not your power supply if at fault and you will need an alternative. If it does then somewhere between the battery and mount/mini-pc is faulty, first check the cable by measuring the battery voltage follow by each plug end at the mount and mini-pc. If all is good the fault is either the mini pc or the mount.



#18 OldManSky

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Posted 30 March 2020 - 07:49 PM

Mini pc are very sensitive to voltage below 12vdc. If it drops to 11.8 it may shutdown. You can use voltages higher but first check if it has tolerance above 12 vdc before trying this out. I operate mine with 13 volts without problems. I have seen some with max voltage of 20 vdc. When you turn your mount on, it might have a quick drop due to demand which could be enough to create a shutdown.

This.

My Beelink mini-PC is just fine with 12-13V, and so is everything else in my system (much like yours, and powered by a 30A power supply).  So I set the power supply (via the adjustable output voltage pot) to 12.3V with no load.  On start-up it drops to 12.18V, very briefly -- then stabilizes at 12.28V and stays there all night.  Without the slightly higher setting, it would drop below 12V when everything switches on.  Control box image below.

Attached Thumbnails

  • obs_march28_6.jpg


#19 NoDarkSkies

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Posted 30 March 2020 - 08:53 PM

I do have a powered USB hub I can add into the troubleshooting.  The rig is headless (I remote desktop into it from any convenient device) so it doesn't need anything other than cameras, mount, and (later) focuser motor connected via USB.  If the system behaves differently from a USB hub, I'd be curious to know why.

Remove the USB Hub Power from your PSU and plug it into the Wall to test, just thinking out of the box.


Edited by NoDarkSkies, 30 March 2020 - 08:54 PM.


#20 GoldSpider

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Posted 30 March 2020 - 09:55 PM

Remove the USB Hub Power from your PSU and plug it into the Wall to test, just thinking out of the box.

I'll try that too, though the USB hub isn't currently a part of the rig.



#21 carolinaskies

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Posted 30 March 2020 - 10:01 PM

I'll assemble the whole system inside and post some pictures.

 

Regarding this part of your post, perhaps you can guess as to whether or not the two separate powerpole outputs are actually separate outputs.  Easiest thing to do, of course, is to test this.

 

Link to photo of unit showing powerpole connectors

 

Edit:  I could always just use the wall-wart that came with the PC since the 12v power supply is plugged in to AC anyway if I wanted to make this easy on myself, but where's the fun in that?

If the power supply came with a manual(can't find one on their website) I would check to see if the front power poles are reduced amperage and the rear output is full peak amp available.   This may be the issue, I don't know. 

I'd check those power poles and see what they output in amps to verify what they are delivering.  It's possible they could be limited. 

That's why I hate cheap PS's, they don't actually give you complete information on operation if you run into issues.





  



#22 t-ara-fan

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Posted 30 March 2020 - 10:54 PM

 I think the wire I have running to the mount might be a bit thin (only 24AWG but the mount is specced to draw 2A max) but I'm not sure if that might be a contributing factor.  Short 18AWG run from rigrunner to the mini PC.

 

 

24AWG is very very thin.  Just because it can take 2A without melting doesn't mean it is suitable.

 

Depending what the electronics are in the mount, the mount could see a huge voltage drop initially and just draw more current to try and get enough power. This transient event can cause the 12V going to the PC (and everywhere else) to drop enough to lockup the PC. Does the PC shut off, or just kind of hang?


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#23 GoldSpider

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Posted 31 March 2020 - 06:41 AM

24AWG is very very thin.  Just because it can take 2A without melting doesn't mean it is suitable.

 

Depending what the electronics are in the mount, the mount could see a huge voltage drop initially and just draw more current to try and get enough power. This transient event can cause the 12V going to the PC (and everywhere else) to drop enough to lockup the PC. Does the PC shut off, or just kind of hang?

My plans for the extended stay at home include replacing all of this thin cable. 
 

 

If the power supply came with a manual(can't find one on their website) I would check to see if the front power poles are reduced amperage and the rear output is full peak amp available.   This may be the issue, I don't know. 

I'd check those power poles and see what they output in amps to verify what they are delivering.  It's possible they could be limited. 

That's why I hate cheap PS's, they don't actually give you complete information on operation if you run into issues.

 

I think I still have the manual and will check on this. That would be disappointing.

 

Edit:  According to the ammeter on the power supply, a portable hair dryer (emergency de-dewer) was able to pull 20 amps from the power supply.


Edited by GoldSpider, 31 March 2020 - 08:54 AM.


#24 GoldSpider

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Posted 31 March 2020 - 03:50 PM

I think whoever suggested that these mini PCs are sensitive to voltage might be onto the right answer.  I've had no problem powering the PC on several different 12v battery sources, but the difference with the Jetstream power supply is that it supplies 13.8v.  I'm betting the PC is just more sensitive to minor over-voltages, and is protecting itself by not running this high.  Would a simple 12v voltage regulator like this fix the problem?  Or should I consider a cleaner, better regulated source of 12v power altogether?

 

Edit:  As of today I am unable to get the PC to power on at all while connected to the Jetstream 12v power supply.


Edited by GoldSpider, 31 March 2020 - 03:51 PM.


#25 OldManSky

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Posted 31 March 2020 - 05:55 PM

Will it power on with a 12v AC power brick?

Hopefully You didn’t over-stress the power regulator chip...




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