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Remote Power options - PPS?

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#1 mtc

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Posted 16 September 2020 - 11:47 AM

I currently image when I am plugged into an outlet but am thinking about imaging via a portable power supply.

It appears that many (all?) Portable Power Supplies (I'm thinking in the ~300w range) are limited to 12v 10A output..

I've done my calculation/estimates and I'm at/around 9 for peak.

 

This is my peak power draw:

Device                    DCV DCA 
Sirius EQ-G Mount     12 2
Power Block (12V 10A)   
  DewHeater-Scope    12 0.25
  DewHeater-Finder   12 0.17
  Focuser                    12 1.2
USB Hub                      5 2.5
533 TEC Camera          12 3
      
total peak Draw      9.12A

 

If I use the cigarette output, which can be 10A, would this suffice?



#2 rgsalinger

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Posted 16 September 2020 - 11:55 AM

First of all, the idea that you will be running at 100 percent cooling and, at the same time slewing the mount and have the dew heater turned all the way up and be focusing seems like a real edge case to me. I have a pretty fancy rig that ran very nicely off a 10 amp PS for a long time. Second, I'm not sure what portable supplies you've been looking at but a lot of people just use a battery with a power distribution unit. Look for some threads about it. Personally,

 

I personally now use a lithium power pack these days https://www.goalzero...-power-station/ which is pricey but really convenient and can be easily charged during the day using a solar panel. 



#3 Jethro7

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Posted 16 September 2020 - 12:59 PM

Hello MTC,

I use a 30 AH LiFePo 4 battery and a power converter 12v DC in 17.4 v DC out. For my G11G mount and dew Strips and other gear, It Will run everything all night plus. 

 

HAPPY SKIES TO YOU AND KEEP LOOKING UP Jethro


Edited by Jethro7, 16 September 2020 - 01:00 PM.


#4 H-Alfa

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Posted 16 September 2020 - 01:45 PM

I currently image when I am plugged into an outlet but am thinking about imaging via a portable power supply.
It appears that many (all?) Portable Power Supplies (I'm thinking in the ~300w range) are limited to 12v 10A output..
I've done my calculation/estimates and I'm at/around 9 for peak.

This is my peak power draw:
Device DCV DCA
Sirius EQ-G Mount 12 2
Power Block (12V 10A)
DewHeater-Scope 12 0.25
DewHeater-Finder 12 0.17
Focuser 12 1.2
USB Hub 5 2.5
533 TEC Camera 12 3

total peak Draw 9.12A

If I use the cigarette output, which can be 10A, would this suffice?

I suggest you to keep your calculation, and redo the calculation in an usual situation. Then decide something between, and then multiply this amps to at least the maximum hours duration of a winter night in your location.

I did it and ended with a 100ah lifepo4 that allows me 1.5 nights in summer, 1 in winter. As a second stage I bought a 320W solar panel that recharges the battery in less that 1 day, so you can stay at your remote dark site as long as your food allows.

Hope it helps.

Enviado desde mi Mi 9 Lite mediante Tapatalk

#5 Phil Sherman

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Posted 17 September 2020 - 02:42 PM

I currently image when I am plugged into an outlet but am thinking about imaging via a portable power supply.

It appears that many (all?) Portable Power Supplies (I'm thinking in the ~300w range) are limited to 12v 10A output..

I've done my calculation/estimates and I'm at/around 9 for peak.

 

This is my peak power draw:

Device                    DCV DCA 
Sirius EQ-G Mount     12 2
Power Block (12V 10A)   
  DewHeater-Scope    12 0.25
  DewHeater-Finder   12 0.17
  Focuser                    12 1.2
USB Hub                      5 2.5
533 TEC Camera          12 3
      
total peak Draw      9.12A

 

If I use the cigarette output, which can be 10A, would this suffice?

You need to redo your calculations. The correct way to do this is to convert all current draws to watts then divide by the supply voltage to get amps draw. If you do this, including a little loss for a dc-dc buck voltage converter for the 5v needed by the hub, you get less than 8A. 

 

When calculating maximum power draw, you can ignore the focuser. Your mount draws less than 0.5A while tracking; its maximum draw occurs while slewing. You'll never be focusing while the mount is slewing. This drops the maximum draw to less than 7A.


Edited by Phil Sherman, 17 September 2020 - 02:52 PM.

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#6 mtc

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Posted 19 September 2020 - 05:52 AM

Thanks for the confirmation - looks like this'll be sufficient.
Clear skies!


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