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Question: RAVPower apple fast charger

I was just deciding on buying an apple wireless charger, so I was just looking through amazon. When I started searching things up, I found out about fast chargers, so I went to look to see if there were any that were cheaper on amazon. I found the RAVPower one, and it had apple all over the amazon and website page. I did a little research, and was just wondering, will the RAVPower wireless charger support 7.5w fast charging?

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Nov 18, 2017 10:13 PM in response to Brandon12204 In response to Brandon12204

So, I downloaded the IOS 11.2 Public Beta 4 a couple days ago, and because of that, I decided to see if the fast charging worked with the public beta. So, in my test, i found that it took 26 minutes and 45 seconds for it to charge %25. With that, I did 26.75/25 to get 1.07. 1.07 was how fast it took to charge %1. So with that, I did 1.07 * 100 (for %100) and got 107 minutes for a full charge. This means that it would take 1 hour and 47 minutes for a full charge. With this test, I found out that the RAVpower does charge significantly faster than other chargers even though it doesn't have the flashing green light indication.


*You technically could have just quadrupled the time/charge ratio, but this was a more in depth explanation.

Nov 18, 2017 10:13 PM

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Nov 19, 2017 7:40 AM in response to Brandon12204 In response to Brandon12204

The flaw in your analysis is that the phone does not charge at the highest rate for the entire charge cycle. When the State of Charge reaches 75% the charging rate slows, and tapers off so that it will be zero when the phone reaches 100%. It will reach 75% very quickly, then take much longer to reach 100%. A full cycle will take roughly as long from 75% to 100% as it took to get to 75%.


So the first question is did your 25% figure all occur below 75%. Assuming it did, based on your figures, it will take 3x26.45 minutes to reach 75%, or 80 minutes. It will then take another 80 minutes to reach 100%, for a full charge time of 160 minutes, or about 2 2/3 hours. That's about the same as my 7 Plus using an iPad power source. Note that the estimate for 75% to 100% is from other phones; I don't know the tapered charge rate for the X, as I don't have one to measure.

Nov 19, 2017 7:40 AM

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Nov 19, 2017 9:52 AM in response to Brandon12204 In response to Brandon12204

Brandon12204 wrote:


When was it found that it slows down at %75? It seems unbelievable that it would take an extra 80 minutes just to get %25 of juice.

About 10 years ago. Every iPhone (and every other device powered by Lithium technology batteries) reduces the rate of charge as it approaches full charge. The reason? Overcharging it even once will kill the battery, and possibly cause it to catch fire. Virtually every smartphone and tablet on the market uses the same charge regulating chip, so they all work the same way. It's even described in Apple's battery documentation.


However, I know because I've measured charging currents on many devices over the years. It's easy to do; it requires a ~$20 investment in a USB power meter. That's how I know that iPhones from the first through the 5 charged at a 5 watt rate, regardless of the power source. Starting with the 5S Apple increased the charging rate below 75% to 7.5 watts, so if you have a USB power source with more than a 5 watt output (e.g., an iPad USB adapter) your 5S would charge faster with the iPad adapter than it would with the "cube" adapter the phone ships with. Starting with the 7, the initial charge rate is 10 watts.


The best way for you to check the charge rate of the RAVPower is to do a controlled test using it, then using an iPad power adapter (which will definitely fast charge the X). Use the same SoC range for both tests.

Nov 19, 2017 9:52 AM

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Nov 19, 2017 10:55 AM in response to Brandon12204 In response to Brandon12204

See the following:

https://www.macrumors.com/2017/11/14/ios-11-2-faster-wireless-charging-iphone-x/

It includes:

MacRumors received a tip about the new feature from accessory maker RAVpower this evening, and tested the new charging speeds to confirm. Using the Belkin charger that Apple sells, which does support 7.5W charging speeds, the iPhone X was charged from 46 to 66 percent over the course of thirty minutes.

At 7.5 watts, Apple's wireless iPhones do not support the same wireless charging speeds that are available on some other Qi-based smartphones, as the current Qi 1.2 standard allows for up to 15W of wireless charging power. Still, 7.5 watts is better than 5 watts and should offer some noticeable improvements for iPhone 8, 8 Plus, and X owners.

Nov 19, 2017 10:55 AM

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Question: RAVPower apple fast charger