AP1100 voltage


ap@CaptivePhotons.com
 

I have an AP1100 on the way.  Any moment now. 

I plan to use it in my back yard mostly, where AC power is available, but occasionally take it to a dark site with batteries.  I redid my batteries and wiring in prep, switching to powerpoles, and now have two set up, and the tripod has two 12V inputs; at home I will use two linear power supplies, and in the field two batteries on the same inputs; nice short wires, 10, 12 and 14AWG (in different parts). 

In recent notes I see indications that higher voltages are better (though that was a Mach 2).  I also recall George suggesting a dedicated power supply that is variable.  The manual says do not exceed 16v, and recommends higher for colder and heavier loads, which I will not have (50# or so max, S. Florida temps). 

Honestly I do not much care about faster slew speed, I just want reliability and stability. 

So my question is kind of a two-for: 

What voltage should I dial in on the adjustable power supply I am getting when using AC power?  Just normal batter voltage (let's say 13v)?

And depending on that answer, is there any point in my including a buck converter to get a bit more voltage from the battery scenario for occasional use?   (It's a group 24 deep cycle marine; it's plenty large that I should not even get to half capacity in a long winter night, so it should stay over 12.3v or so).

And yes, this is a minor detail but I have to DO SOMETHING while I wait.  :) 

Linwood


Dean Jacobsen
 

There is a lot of great information in the GTOCP4 Servo Motor Drive System manual that is posted on the AP1100 product page.  Appendix B is titled Power Considerations and has a lot of useful information regarding power for the 1100 in different scenarios.
--
Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/


Roland Christen
 

You can use anywhere from 12.5 to 18 volts on the 1100 mount. So if you have a variable voltage supply, dial it in to about 14.5 volts. It will work at up to 24 volts but will get quite hot, so it's not recommended. The controller will not get fried unless you exceed about 28 volts on the input. Best to stay below 18 for long term health.

Rolando


-----Original Message-----
From: ap@... <ap@...>
To: main@ap-gto.groups.io
Sent: Tue, Jul 13, 2021 8:11 pm
Subject: [ap-gto] AP1100 voltage

I have an AP1100 on the way.  Any moment now. 

I plan to use it in my back yard mostly, where AC power is available, but occasionally take it to a dark site with batteries.  I redid my batteries and wiring in prep, switching to powerpoles, and now have two set up, and the tripod has two 12V inputs; at home I will use two linear power supplies, and in the field two batteries on the same inputs; nice short wires, 10, 12 and 14AWG (in different parts). 

In recent notes I see indications that higher voltages are better (though that was a Mach 2).  I also recall George suggesting a dedicated power supply that is variable.  The manual says do not exceed 16v, and recommends higher for colder and heavier loads, which I will not have (50# or so max, S. Florida temps). 

Honestly I do not much care about faster slew speed, I just want reliability and stability. 

So my question is kind of a two-for: 

What voltage should I dial in on the adjustable power supply I am getting when using AC power?  Just normal batter voltage (let's say 13v)?

And depending on that answer, is there any point in my including a buck converter to get a bit more voltage from the battery scenario for occasional use?   (It's a group 24 deep cycle marine; it's plenty large that I should not even get to half capacity in a long winter night, so it should stay over 12.3v or so).

And yes, this is a minor detail but I have to DO SOMETHING while I wait.  :) 

Linwood

--
Roland Christen
Astro-Physics


ap@CaptivePhotons.com
 

  • You can use anywhere from 12.5 to 18 volts on the 1100 mount. So if you have a variable voltage supply, dial it in to about 14.5 volts. It will work at up to 24 volts but will get quite hot, so it's not recommended. The controller will not get fried unless you exceed about 28 volts on the input. Best to stay below 18 for long term health.

 

Thanks, Rolando, 14.5v.  Perfect, I was hoping for a dial-in number.   Though I am confused by the 18v,24v; the manual says not to exceed 16v (e.g. page 50 of the referenced document below).  But not an issue, 14.5 looks good. It’s not like I’m trying to overclock a PC.

 

So back to the second half – when on batteries, I’ll be closer to the 12.5, probably starting the night at a bit over 13 and dropping.  If I hit 50% capacity I will be more like 12.2v less resistance loss.  So do I need a buck converter to get back up?  Or is the difference for a few hours occasionally moot?

 

I am somewhat resisting the buck converter because since it will hold the voltage up it’s a switching device and introduces some noise.

 

  • There is a lot of great information in the GTOCP4 Servo Motor Drive System manual that is posted on the AP1100 product page.  Appendix B is titled Power Considerations and has a lot of useful information regarding power for the 1100 in different scenarios.

 

Dean, thanks for that pointer, I thought I had downloaded all the manuals but missed that one.  There’s a LOT of documentation, which is good, but it does make it easier to miss pieces.  Thank you.

Linwood

_._,_._,_


M. Collins
 

  There's not much to fear from good switching supplies. I've tested many under load, and rarely see more than a few millivolts of AC measured either with a meter or on an oscilloscope. Some cameras, particularly older designs, may couple noise of that amplitude through to the images they produce, but a GTOCPx will not be adversely affected in the slightest.


Christopher Erickson
 

The actual top recommended voltage isn't an absolutely precise number because variables like altitude, ambient temperature, relative humidity and localized air movement play significant roles in heat dissipation. 

14.5V is a reasonable, average suggestion. Personally I would de-rate that a bit in high, dry, hot environments. Maybe 12 to 13.7 volts.

In some cases I might even consider putting an auxiliary heat sink plate with a fan on the back of some hotter electronic devices in those kinds of extreme environments. Or use liquid cooling and propylene glycol or some other heat conductive fluid with extended temperature specifications.

Usually not issues that most amateurs have to deal with.

I hope this helps.

-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   


On Wed, Jul 14, 2021, 7:05 AM ap@... <ap@...> wrote:
  • You can use anywhere from 12.5 to 18 volts on the 1100 mount. So if you have a variable voltage supply, dial it in to about 14.5 volts. It will work at up to 24 volts but will get quite hot, so it's not recommended. The controller will not get fried unless you exceed about 28 volts on the input. Best to stay below 18 for long term health.

 

Thanks, Rolando, 14.5v.  Perfect, I was hoping for a dial-in number.   Though I am confused by the 18v,24v; the manual says not to exceed 16v (e.g. page 50 of the referenced document below).  But not an issue, 14.5 looks good. It’s not like I’m trying to overclock a PC.

 

So back to the second half – when on batteries, I’ll be closer to the 12.5, probably starting the night at a bit over 13 and dropping.  If I hit 50% capacity I will be more like 12.2v less resistance loss.  So do I need a buck converter to get back up?  Or is the difference for a few hours occasionally moot?

 

I am somewhat resisting the buck converter because since it will hold the voltage up it’s a switching device and introduces some noise.

 

  • There is a lot of great information in the GTOCP4 Servo Motor Drive System manual that is posted on the AP1100 product page.  Appendix B is titled Power Considerations and has a lot of useful information regarding power for the 1100 in different scenarios.

 

Dean, thanks for that pointer, I thought I had downloaded all the manuals but missed that one.  There’s a LOT of documentation, which is good, but it does make it easier to miss pieces.  Thank you.

Linwood