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A roommate has bought a OnePlus One (OPO) phone. When I tried charging my Nexus 5 with the charger of OPO I found that it charged my Nexus device amazingly fast. I'm talking 3-4 times faster charging than the normal charger does (and about 20-30 minutes to charge completely).

I was told this fast charger could result in negative long term effects on the battery. Is there any truth to it? And why would it happen?

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    It appears the default charger for the Nexus 5 is only .85 amps. Most newer chargers put out at least 2.0 amps. So that would charge a lot faster. In your 20-30 min charging session, is that from dead to full or what? But to be honest, as long as you are getting the same battery life out of the battery and the battery isn't getting super hot while charging, I wouldn't worry about it. Heat is the number one killer for batteries. I use my Note 4 charger for all my devices and I haven't notice any type of battery life degrading. That being said, OEM's would like you to use the default charger.
    – jer3my
    Commented Jul 15, 2015 at 23:59
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    Yes that's from dead to full. It's insane. It doesn't get hot or anything so maybe it's ok
    – yuvi
    Commented Jul 16, 2015 at 5:20
  • Point of comparison: The Nexus 6 has the second-best rated charge time in a phone on Anandtech, at 1.89 hours compared to Nexus 5's 2.54 hours. I have it plugged into a QC 2.0 charger right now. It's pulling only 1.75A. Nexus 5 can't pull 2A from a 2A charger. It's simply not possible. The best I've ever seen a Nexus 5 do, across a wide range of chargers, is 1.2A, and it certainly gets warm. As well, 2A wouldn't add up to 20-30 minutes. 30 minutes would require a 5.5A flow, which simply doesn't exist.
    – TurboFool
    Commented Jul 16, 2015 at 5:34
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    I edited my answer to reflect all my research. Any way you look at it, that speed is impossible. As for checking flow, I use an app called Battery Monitor Widget that's always been extremely helpful. It's saved my butt in figuring out what combinations of charger and cable allowed each of my phones to charge at their fastest. Highly recommended.
    – TurboFool
    Commented Jul 16, 2015 at 5:50
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    You can see my answer here for more details android.stackexchange.com/a/133785/131553
    – beeshyams
    Commented Jan 9, 2016 at 4:59

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Your phone isn't capable of charging any faster than it's built to charge. The Nexus 5 had very limited support for Quick Charge 1.0 due to its processor, although my understanding is that this functionality wasn't enabled for the 5. But the phones are designed to pull only as much power as they can safely pull. If it can't take it, it'll negotiate a lower rate with the charger.

That said... 20-30 minutes to charge completely doesn't sound possible. I'm not aware of a single phone that can do that. So something's a little bit odd there...

EDIT: Did some research and confirmed that this charge speed simply isn't possible. A few points:

  1. The most current I've ever seen a Nexus 5 pull from any charger (and I've tried a very wide range) was 1.2A. And boy was that fleeting. At that rate, it would charge fully in 2.3 hours, according to this battery charge time calculator. That's actually a little less than Anandtech found in their comparison chart found in the OnePlus One review, listing its charge time at 2.54 hours. That's more realistic, because as I said, getting a full 1.2A for more than a moment or two was quite rare, and phones draw less current the closer they are to full.
  2. According to that same review, the Nexus 6 is the second-fastest charging phone on the market (or was at that time), charging from 0% to 100% in 1.89 hours. Faster than the Nexus 5, but still a quarter of the speed you're saying you're getting on the Nexus 5. I just plugged my Nexus 6 into a QC2.0 charger, which I believe is still considered the fastest phone charging tech anyone's using, and right now it's pulling about 1.75A, which would be about 2.25 hours to fully charge. That said, it's nearly full, so that's when it slows down, which likely accounts for the difference between my figure and Anandtech's.
  3. Using that same battery charge calculator, to fully charge the Nexus 5 at your WORST-case scenario of a full 30 minutes, would require 5.52A of power. 8.29A for 20 minutes. Even the iPad, which has a massively larger battery and needs much more power to charge at a reasonable rate, uses only a 2.1A.
  4. The OnePlus One charger outputs only a maximum of 2A according to its own label. The best that charger could possibly do in an ideal world where it somehow can charge the Nexus 5 at full speed the ENTIRE time, is 1.38 hours.

Any way you slice it, it's not possible for a Nexus 5 to fully charge, with ANY charger, much less the OPO charger, in 20-30 minutes. If yours is informing you that it is, your Nexus 5 is faulty and displaying incorrect battery information. It's either displaying 100% when it's not full, or shutting itself off WAY before it's reached 0%. It's possible that this is an indication of the OPO charger somehow interacting badly with it, in which case I may rescind my initial advice that it can't hurt.

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    I timed it and found it charged 22 percent within 16 minutes, meaning a 1.375 percent for each minute, or around 72 minutes to charge completely. That's less than my estimated 20-30 minutes, but it's still faster than what you claim is the fastest possible
    – yuvi
    Commented Jul 16, 2015 at 12:44
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    But as I mentioned, they charge at their fastest speed when the battery's low and slow as the battery fills. So that would still be pretty much in line. My figures were also based on the industry-standard expected 20% efficiency loss. If we go with a rare 10% efficiency loss, with it somehow maintaining that speed the ENTIRE time, we get 76 minutes, which is within the margin of error of your figure. Sounds like the charger is very efficient. Also keep in mind when the phone reports the battery's empty, it's usually not really empty. All-in-all, your new figures aren't impossible. 20-30 was.
    – TurboFool
    Commented Jul 16, 2015 at 21:32
  • Also, were you able to use that app to get actual figures on current?
    – TurboFool
    Commented Jul 16, 2015 at 21:35

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