# Is Fast Charge Safe?



## TenderloinShadow

Hey so I'm running AOKP JB Build 1 with Imoseyon's Lean Kernel 0.7 on my VZW S3. I notice one of the options I have is for a fast charge feature. Now the concept of charging faster sounds awesome to me, but I've held back thus far because I have some concerns. I'm under the impression (and please, correct me if I'm wrong about all this) that batteries and chargers are designed to deliver a certain amount of power, and if we pump extra power faster through them we risk damaging/decreasing the lifespan of our batteries.

So my question is: is this the case? Or is fast charge truly safe? What, in general, are the risks involved in fast charge, and would anyone really recommend it?

Thanks.


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## bobloblaw1

All fast charge does is allow you to charge at the wall charger rate from a usb port. That's it.

Risks: you lose usb connectivity until you disable fast charge. So defer making any changes that might require adb use to get out of a boot loop.

Sent from my htc_jewel using RootzWiki


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## joemagistro

bobloblaw1 said:


> All fast charge does is allow you to charge at the wall charger rate from a usb port. That's it.
> 
> Risks: you lose usb connectivity until you disable fast charge. So defer making any changes that might require adb use to get out of a boot loop.
> 
> Sent from my htc_jewel using RootzWiki


true to a point... its safe for your phone.... however it allows the device thats charging your phone to put out more voltage and could actually mess it up if its not meant to do that.... Regardless i use 12volts dc to fastcharge my phone witth usb fastcharge soo it really dont matter


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## Tidefan22

I've always used it and it ain't hurt my nexus

Sent from my Galaxy Nexus using Xparent Blue Tapatalk 2


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## MistaWolfe

There has been many reports of it borking your USB port to the point of being unusable.

I believe it happened to a dev here.

Sent from my SCH-I535 using Tapatalk 2


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## mendedtimbo

I have messed up two usb ports on my nexus, I'm sure it was because of the fast charge option.

Sent from my SCH-I535 using Tapatalk 3


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## kameleongt

I've used it from gnex to gs3 since its availability and have had no issues I rarely connect to my PC and by rare only time I did it since owning the gs3 was to load old pics ringtones backups

Sent from my SCH-I535 using Tapatalk 2


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## yarly

Read through this

http://rootzwiki.com/topic/31181-att-kernel-devs-usb-fast-charge/page__hl__%2Bfast+%2Bcharge


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## joemagistro

I don't understand or agree that it could mess up the usb port on the phone. Only because it puts out the same voltage as if you were to use ac to charge the phone.... The host device maybe, but not your phone

Sent from my T999 SGS3


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## yarly

There's more to electricity than voltage. Otherwise shocking someone with static electricity (where voltage is well over 1000 volts or more) would be severely hurting people







.

In other words, it's all about the current and that can vary while the voltage remains the same.

EDIT: forgot to mention the phone will regulate how much ampage it can pull...well unless there's some sort of bug that's very unlikely, but plugged into USB, it gets 500 milliamps and plugged into AC it gets I think 700 milliamps. Fast charge just tells it to pretend it's plugged into AC.

So fry your device? No, probably not unless someone was really screwed up in the kernel.

Fry your charging port on the charger's end? More likely if it has faulty wiring.


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## icanhazdroid

yarly said:


> There's more to electricity than voltage. Otherwise shocking someone with static electricity (where voltage is well over 1000 volts or more) would be severely hurting people
> 
> 
> 
> 
> 
> 
> 
> .
> 
> In other words, it's all about the current and that can vary while the voltage remains the same.
> 
> EDIT: forgot to mention the phone will regulate how much ampage it can pull...well unless there's some sort of bug that's very unlikely, but plugged into USB, it gets 500 milliamps and plugged into AC it gets I think 700 milliamps. Fast charge just tells it to pretend it's plugged into AC.
> 
> So fry your device? No, probably not unless someone was really screwed up in the kernel.
> 
> Fry your charging port on the charger's end? More likely if it has faulty wiring.


I read through all the comments on the attempted CM commit you linked, and seeing it from their viewpoint it just sounds scary to me now. I never had a problem on my Nexus but I'd rather not risk my S3


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