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Power through USB ports

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#1 coralaholic

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Posted 29 March 2020 - 02:37 AM

Hello!

 

My polemaster and guide camera (QHY 5L-ii) are connected to my laptop USB 3.0 ports, they draw battery from the USB ports, with an external laptop mobile battery (65Wh) charging the laptop through an USB Type-C port, the laptop can last for around 4 hours at room temperature before it dies, it works just okey but I wonder whether the polemaster and guide camera can be connected to a self power USB hub (connect to a 12V mobile battery) instead to avoid draining off the laptop power?

 

If it works, any one experienced any particular problems if the imaging camera is also connected to the USB hub but not directly to the computer? Will the images sent through the USB cable slow down the frame rates of the polemaster and guide camera?

 

Do I still need the USB hub if I'm getting a raspberry pi based computer (e.g. StellarMate), it needs 5.1V. 

 

Appreciated if anyone can share the experience, many thanks!

 

 

 

 

 

 



#2 Noah4x4

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Posted 29 March 2020 - 03:09 AM

It would help people offer you suitable guidance if you published your equipment list in your signature, because the answer depends on what camera etc. My camera is useless without 12v 2A power. 

 

But USB power is generally fraught with challenges. Cable lengths are very limited, even if using active cables and powered hubs. I reckon more money is wasted on resolving USB/power  issues than almost any other problem.

 

If your sole problem is extending laptop battery life, my recommendation is try to find a way to extend supply to your laptop rather than mess with other solutions. Might buying a spare laptop battery be sensible? A MaxOak K2 50,000 mAh device will externally power a 19v 2.5A laptop for over eight hours.

 

There are also solutions with even greater longevity. For example. If your current solution works, but you run out of laptop power too soon, you could connect a 12v/110v (US) DC/AC inverter to a high Amp hour 12V battery. Then power your laptop from inverter using its regularly mains AC/DC adapter for greater longevity. I am involved with outside sports broadcasting and I use an 12v 18Ah mobility scooter battery and 12v/220v 300 watt (UK) Bestek Inverter to give me an equivalent of off-grid mains power. 


Edited by Noah4x4, 29 March 2020 - 03:14 AM.


#3 coralaholic

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Posted 29 March 2020 - 04:01 AM

It would help people offer you suitable guidance if you published your equipment list in your signature, because the answer depends on what camera etc. My camera is useless without 12v 2A power. 

 

But USB power is generally fraught with challenges. Cable lengths are very limited, even if using active cables and powered hubs. I reckon more money is wasted on resolving USB/power  issues than almost any other problem.

 

If your sole problem is extending laptop battery life, my recommendation is try to find a way to extend supply to your laptop rather than mess with other solutions. Might buying a spare laptop battery be sensible? A MaxOak K2 50,000 mAh device will externally power a 19v 2.5A laptop for over eight hours.

 

There are also solutions with even greater longevity. For example. If your current solution works, but you run out of laptop power too soon, you could connect a 12v/110v (US) DC/AC inverter to a high Amp hour 12V battery. Then power your laptop from inverter using its regularly mains AC/DC adapter for greater longevity. I am involved with outside sports broadcasting and I use an 12v 18Ah mobility scooter battery and 12v/220v 300 watt (UK) Bestek Inverter to give me an equivalent of off-grid mains power. 

 

Thanks, I have included my equipment list in my signature, see if it is useful.

 

I'd like to limit the battery capacity to less than 160Wh since I need to carry the battery on plane, so a high amp hour 12V battery is not an option for me.




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