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This is neat....
- Thread starter a-m-k
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Realistically this only applies to iPhones as of iPhone 6, and even then to a somewhat limited degree as far as how much more power they pull in from a charger that can provide more power.
You know what's really neat? Proper thread titles.
I use the standard iPhone charger next to the bed for when the phone has all night to charge. Then I have a iPad charger plugged in next to the couch for if I need a quick fill up. I also have a 6' lighting cable too so I can charge while using a device.
I found that the impact is even greater when using an external battery for quick charge on the go. Upgraded to a 2.1amp battery and really speeds things up.
Easy there. No need to spread more confusion about batteries than we already have.
I can assure you that the battery won't last 8-10 years if you use a lot of cycles. Not even if you constantly keep the charge between 40-80%. Li-ion batteries doesn't work well with heat, deep discharge or over-charging.
Apple used to claim that the iPhone batteries could remain at 80% capacity after 400 charges. iPad could remain at 80% capacity after 1000 cycles. But I wasn't able to find this information anymore...
I didn't just pull this out of my rear. Below is what Battery University writes on the topic. In addition I have seen these figures in other places. Li Ion power packs in cars are expensive to replace, over $10,000. In order to provide extended life, eight to ten years. The charging circuit in cars like the Prius keep the charge between low 50-60% and no higher than 70-80%. This reduces capacity per charge but provides a very long battery lifetime, as customers would be quite unhappy to replace battery in two years for 10 grand.
I can assure you the battery could get that kind of life. And I don't think knowing that is confusing. I never claimed that after ten years you will still have 80% capacity.
At the end of this eight to ten year cycle the battery will hold less than 50% of its capacity, but it will have lasted that long. I would never limit myself to only charging 20 percent at a time as I would need a power adapter with me everywhere I go. And keep adding this small percentage several times a day.
By the chart below you can see just by keeping the discharge/recharge rate in mid 50% you can triple the battery capacity life to 1,500 full cycles. Easily getting you to 5-6 year point. You won't be able to run phone all day. All I am saying is it is a choice. But again who keeps the phone that long.
Battery University quote:
Although a battery should deliver 100 percent capacity during the first year of service, it is common to see lower than specified capacities, and shelf life may contribute to this loss. In addition, manufacturers tend to overrate their batteries, knowing that very few users will do spot-checks and complain if low. Not having to match single cells in mobile phones and tablets, as is required in multi-cell packs, opens the floodgates for a much broader performance acceptance. Cells with lower capacities may slip through cracks without the consumer knowing.
Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life. The exception may be a periodic calibration of the fuel gauge on a smart battery or intelligent device.
Table 2 compares the number of discharge/charge cycles Li-ion can deliver at various DoD levels before the battery capacity drops to 70 percent. All other variables such as charge voltage, temperature and load currents are set to average default settings.
Table 2: Cycle life as a function of
depth of discharge.
A partial discharge reduces stress and prolongs battery life. Elevated temperature and high currents also affect cycle life.
100% DoD 300 - 500
50% DoD 1,200 - 1,500
25% DoD 2,000 - 2,500
10% DoD. 3,750 - 4,700
Lithium-ion suffers from stress when exposed to heat, so does keeping a cell at a high charge voltage. A battery dwelling above 30°C (86°F) is considered elevated temperature and for most Li-ion a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge for an extended time can be more stressful than cycling.
I had to Google it to find it (I didn't try too hard but definitely couldn't get to this site via Apple's site navigation) - http://www.apple.com/batteries/service-and-recycling/
Someone I know has an iPhone 4s with almost 900 charge cycles (they let me hook it up to my Mac with coconutBattery) and he barely gets 6 hours out of it (standby) - they curse it and swear they'll never get Apple again because of its battery even though I mention the below information. :/
"
Your battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles. The one-year warranty includes service coverage for a defective battery. If it is out of warranty, Apple offers a battery service for $79, plus $6.95 shipping, subject to local tax.
Your battery is designed to retain up to 80% of its original capacity at 1000 complete charge cycles. The one-year warranty includes service coverage for a defective battery. If it is out of warranty, Apple offers a battery service for $99, plus $6.95 shipping, subject to local tax."
After 250+ charge cycles on my iPhone 6+ with a 3.8a Anker wall charger (yeah it's fast - and yeah, I know phone only pulls what it wants) - I had 97.8% battery capacity from design capacity according to coconutBattery. Wife was at 96% after almost 400 charge cycles with her iPad charger on her 6+.
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Lots of awesome information in the post above. I give it my stamp of approval. And to help feed my battery OCD I would love to tell the iPhone to keep its battery between 40-80% (yes, I'd need to carry my Anker battery with me everywhere, but less wear and tear would be awesome). That said, I only got to 250~ cycles on my 6+ before I upgraded. So, OCD it is cuz I'll always upgrade way before I hit 500 charge cycles.
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I ran across this post and wondering if anyone has any input on whether its accurate or not. (I'm attaching the text of the post in case the link is not permitted.)
https://discussions.apple.com/message/28978859#28978859
Lawrence Finch:
"The first response is partly right, but for the wrong reason. Every USB adapter ever made has the same voltage output: 5 Volts +-0.5 volts. The important value is the CURRENT (amperes or amps) that the adapter can supply. Any device will only use the amperage it needs, regardless of what is available.
The short answer is the 12 watt adapter (which can supply 2.2 amps) will charge an iPhone 6 or later slightly faster than the adapter that comes with the phone, which can only supply 1 amp. But even though the adapter can supply 2.2 amps, the charging circuit in the iPhone 6 will only use 1.6 amps. So it won't be twice as fast. For all iPhones prior to the 6 there was no benefit to using a higher power adapter, because the phone would only draw 1 amp regardless of what the adapter could supply.
There's another factor at work; the phone will fast charge to about 60%, then slow down the charging rate to avoid any possibility of overcharging. Most of the charge time is going from 60% to 100%. If you watch closely, starting at zero the phone will reach 60% in about 40 minutes with the 12w adapter, and about an hour with the 5w adapter. But the time to full charge will be another 2 hours. The higher current charger is only a benefit in the initial charging, not from 60% to 100%. So overall you save about 20 minutes with the 12w adapter."
https://discussions.apple.com/message/28978859#28978859
Lawrence Finch:
"The first response is partly right, but for the wrong reason. Every USB adapter ever made has the same voltage output: 5 Volts +-0.5 volts. The important value is the CURRENT (amperes or amps) that the adapter can supply. Any device will only use the amperage it needs, regardless of what is available.
The short answer is the 12 watt adapter (which can supply 2.2 amps) will charge an iPhone 6 or later slightly faster than the adapter that comes with the phone, which can only supply 1 amp. But even though the adapter can supply 2.2 amps, the charging circuit in the iPhone 6 will only use 1.6 amps. So it won't be twice as fast. For all iPhones prior to the 6 there was no benefit to using a higher power adapter, because the phone would only draw 1 amp regardless of what the adapter could supply.
There's another factor at work; the phone will fast charge to about 60%, then slow down the charging rate to avoid any possibility of overcharging. Most of the charge time is going from 60% to 100%. If you watch closely, starting at zero the phone will reach 60% in about 40 minutes with the 12w adapter, and about an hour with the 5w adapter. But the time to full charge will be another 2 hours. The higher current charger is only a benefit in the initial charging, not from 60% to 100%. So overall you save about 20 minutes with the 12w adapter."
There is an additional point you failed to take into account, that will cause the older phones to charge faster using the iPad charger. I have timed it and proven it to myself when I still had older phones. So I disagree with your statement that the higher wattage won't charge phones before the 6 faster. Here is why.
Most people do not turn their iPhones off completely when charging. Some use the phones, screen on, other let it sleep, but the radios are still transmitting and receiving while the phone sleeps. Depending on what apps are doing in background, what diagnostics are being reported, what updates are happening, what location data is being collected and sent, there can be a substantial amount going on with a good deal of power being consumed.
Using the 1 amp power adapter cube means that not all the amps are going to the charging circuit. Depending on various radios and their respective reception, weak signal needing more power. Now if the owner is also using the phone while charging, screen on, perhaps bright, and playing a game, listening to downloading music, streaming a movie, etc. Most of the power adapter amperage is being consumed by usage and is not available for charging. Charging will take many hours.
Now switch over and use the iPad 2.2 amp power adapter under the same conditions. All of a sudden you will have abundant power to run the iPhone and plenty, most likely maximum power to charge the battery at the same time. This condition or situation exists for all the iPhones. Pre 6, the 4, 4s, 5, 5s, 5c, 5SE as well as 6 and 6s.
This is why many people have noted that their charge time IS REDUCED using the iPad power adapter on older phones.
I heard that too and used both the original charger + lightning to usb cable from the large iPad Pro for my iPhone 6s Plus and a message came up what said something like this accessory is not designed for using it with the iPhone. I pulled it very fast out then. 
It wasn't my point but I do have a question about yours... If an older phone's max input is 1 amp how would using a bigger charger change that? The consumption rate of the screen and processor is the same regardless of chargers and the max input is limited by the hardware. (Assuming the smaller charger is capable of providing the max consistently of course.)
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Sorry, was Lawarence Finches point.
First off the charger is inside the iPhones. The cube you plug into the wall is the power adapter, not the charger. It's a transformer converting 110v 60 Hz and 220v 50 Hz to 5v DC. The charging circuit is what recharges the battery, it is one of the users of the power provided. Remember a sleeping iPhone can be using a lot of current to run the radios, especially in aweak signal area. Sleeping is NOT off.
The charger inside the phone takes the available current from the power adapter to charge the batteries. This charger in the older iPhones can use up to 1 amp. However if the phone is using part of this current to run other things, the radios, the processor, the screen, not all of the 1 amp of current the power adapter is providing is available for the charging circuit. Something less than 1 amp is left to charge the battery.
The charging circuit in the older iPhones can not use more than 1 amp, so if the phone is off (not asleep) or in airplane mode with screen off the charger gets all of the 1 amp. Adding a stronger power adapter, 2.2 amp iPad adapter does not increase the amps sent to the battery. Still only maximum of 1 amp.
Now if the phone is asleep, with radios going, or is on, screen glowing, processor working, music playing all this consumes a large part of the I amp the power adapter is supplying to the phone. This leaves only the remaining current for the charging circuit inside the phone to charge the batteries. If you use the higher current iPad power adapter then there is enough current to power the phone and still leave the 1 amp the charging circuit can use for the battery.
Think of you taking a shower, you are the battery and the shower head is the charging circuit. You are getting the maximum flow from that shower head. But if someone flushes the toilet, washing machine is turned on, and someone waters your lawn, you get less flow in the shower. The water is being used elsewhere. But if I connect a fire hose to your house, (the iPad power adapter), then all the faucets get more water and the shower head will spray you with the same volume even if someone flushes.
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But then you are saying the phone can take in more than 1 Amp and it's just that only 1 Amp max from that could be used for charging, yet from various discussions about this before the limitation wasn't as much as on how much the charger could use in the phone but how much the phone can take in overall, with that being 1 Amp max until iPhone 6.
Just buy the original Anker 5 port charger, it can charge your phone faster and you can charger another 4 device at the sametime without losing charging speed. I already bought 5 of them, one for each room.
That's been my experience. Charge circuit can draw up to 1 amp to charge battery. My 5s did charge faster using the iPad power adapter when I was using it at the same time as charging. I can only conclude that the phone overall did draw more current than 1 amp. I did not compare charge times with the 5s turned off. I no longer have that phone so can't check but I believe others when they say the charge circuit alone will not draw more than 1 amp regardless of which power adapter is used. Perhaps someone that has the phone can try it both ways and report.
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