Charge via laptop

AFPoster

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Oct 23, 2011
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One of my biggest complaints in the past is the fact that no Android device could charge off of my MacBook Pro. Has anyone with a Nexus 9 been able to charge the device off a laptop? I'm getting this device this week and just want to make sure it can charge this way.
 

phlow

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It will charge off a USB from your laptop (I'm on Windows 8, but as long as you have a powered USB it should work. This tablet is a pretty slow charger so I think you are still going to want to carry your charger with you, it's much faster directly off mains voltage via HTC adapter.
 

Shilohcane

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Computer USB ports were never designed to charge big peripheral devices and limit the amps they send out the computer port. If laptops didn't limit the Amps it would overload the laptop computers battery causing them to overheat and short their life. This is like a circuit breaker in your home. Also, there are different types of USB ( 1, 2, and 3 ) ports and USB cables rating that limits Amperes to power peripherals. USB ports on computer don't produce enough Amps to charge big lithium polymer batteries.

Most tablets need 1.2 A to 2.1 A to charge. My old 2012 Nexus 7 needed a 2.1 A charger or it discharged when I plugged it a lower 1.2 A charger. My 2013 Nexus 7 will charge with a 1.2 A charger but the 2.1 A works faster. Even the higher computer ports USB 3 only produces 0.900 A ( or 900 mA). The Nexus 9 has a 6700 mAh battery that would take forever to charge with a USB 3 computer port and most likely would get stuck below 10% of the charge which could also reverse directions trying to charge you laptop.

I had a friend that told me his Samsung Tab 2 tablet wouldn't charge past 10%. I looked at it and he was using a 800 mA Chromecast USB charger and his tablet needed a 12000 mA ( or 1.2 Amp) charger. The weak Chromecast USB charger could only produce enough Amps to get his table to about 10% before it stops charging.

Since you have a Mac Pro this is from their site on USB and charging peripherals

Apple computers and displays with USB 1.1 or USB 2 ports provide:

Up to 500 mA (Milliamps) at 5 V (Volts) to most Apple USB peripherals and all USB peripherals not made by Apple in compliance with USB specifications.

Apple computers with USB 3 ports provide:

Up to 900 mA (milliamps) at 5 V (Volts) to most Apple USB peripherals and all USB peripherals not made by Apple in compliance with USB specifications.
Note: Some USB peripheral devices not manufactured by Apple may have unique power requirements. These may exceed the power allotment on an individual USB port. Those devices may require you connect them to multiple USB ports or may have external power sources that must be present for them to function.

Apple peripheral devices may request more than 500 mA (Milliamps) at 5 V (Volts) from a port to function or to allow for faster charging. Such Apple peripheral devices include:

Apple Computers and Displays: Powering peripherals through USB - Apple Support
 
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AFPoster

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Oct 23, 2011
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Thanks for your detailed response. I guess that's one of the advantages of using an iPad is it can charge off of any Apple device (MacBook Air, Pro, Mac Book) and provide the same charging times as if it were directly into the wall.

HTC support said it would take 9-10 hours to charge, obviously I highly doubt it. They said in the wall is 6 hours, but as most of the posts have written that seems to be not enough time. Android devices are the only ones that struggle to charge off laptops.

Computer USB ports were never designed to charge big peripheral devices and limit the amps they send out the computer port. If laptops didn't limit the Amps it would overload the laptop computers battery causing them to overheat and short their life. This is like a circuit breaker in your home. Also, there are different types of USB ( 1, 2, and 3 ) ports and USB cables rating that limits Amperes to power peripherals. USB ports on computer don't produce enough Amps to charge big lithium polymer batteries.

Most tablets need 1.2 A to 2.1 A to charge. My old 2012 Nexus 7 needed a 2.1 A charger or it discharged when I plugged it a lower 1.2 A charger. My 2013 Nexus 7 will charge with a 1.2 A charger but the 2.1 A works faster. Even the higher computer ports USB 3 only produces 0.900 A ( or 900 mA). The Nexus 9 has a 6700 mAh battery that would take forever to charge with a USB 3 computer port and most likely would get stuck below 10% of the charge which could also reverse directions trying to charge you laptop.

I had a friend that told me his Samsung Tab 2 tablet wouldn't charge past 10%. I looked at it and he was using a 800 mA Chromecast USB charger and his tablet needed a 12000 mA ( or 1.2 Amp) charger. The weak Chromecast USB charger could only produce enough Amps to get his table to about 10% before it stops charging.

Since you have a Mac Pro this is from their site on USB and charging peripherals
 

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