Power from TV/receiver/cable box USB port safe long term?

goelz83

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May 3, 2011
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So I'm definitely no expert when it comes to amperage/voltage but I was wondering if we should be concerned with powering our Chromecast devices through a USB port because of the low amperage output from the port. The charger that is included in the box outputs at 850 mA whereas most USB ports (USB 1.0 and 2.0 specifically) have a max output of 500 mA.

I was just wondering if it would be possible to damage (or cause performance issues) by not providing sufficient to amperage to the device. I know that amperage draw is determined by the device that is being powered (as opposed to voltage which is pushed from the power source) and I just wanted to make sure that it's safe to plug them into a USB port that can only provide 500 mA.
 

Devlyn16

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Nov 11, 2010
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Interesting question. I wonder if the additional power might assist with those having difficulty connecting via wifi.

on the other hand out putting 850 doesn't mean the chrome cast needs 850 to run.
 

Craig King

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Nov 17, 2012
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It is really a hard thing to answer. On computers the USB ports can either have a single fuse on each port or across an entire hub. If the fuse blows then all of the ports associated with it fail. I have seen it happen a few times. On a TV who knows how the ports are expected to run. I wouldn't expect the port to blow anytime soon though. And considering that the ports turn off with the PC the work load on them shouldn't be that great compared to a PC. I probably wouldn't worry about it after thinking it through like that.

On another note though isn't it suggested by Google.

I would also say that for those cases were the USB ports are generaly avaliable and designed to be functional for other uses like media playback and such it may be more robust then lets say a USB based service port.
 

anon(5021)

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Dec 13, 2009
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It is really a hard thing to answer. On computers the USB ports can either have a single fuse on each port or across an entire hub. If the fuse blows then all of the ports associated with it fail. I have seen it happen a few times. On a TV who knows how the ports are expected to run. I wouldn't expect the port to blow anytime soon though. And considering that the ports turn off with the PC the work load on them shouldn't be that great compared to a PC. I probably wouldn't worry about it after thinking it through like that.

On another note though isn't it suggested by Google.

I would also say that for those cases were the USB ports are generaly avaliable and designed to be functional for other uses like media playback and such it may be more robust then lets say a USB based service port.


I hope you don't mind me asking a somewhat unrelated question... but you seem to know way more about this stuff than I do. I have a Chromecast. My plasma tv is an older one and the only USB port it has is the Service USB port. I know Google said to not use this as the power source for the Chromecast but I am wondering why? I know the power to that port is killed when the TV is off... is that why (is it harmful to the Chromecast itself?)?

Thanks in advance!