The truth about your iPad batteries.

Question

Level 1

4 points

The truth about your iPad batteries.

I like my iPad. What I don't like is the misguided statements made by Apple website about the recommended practices on how to prolong your battery life. I'm writing post to clear some general battery misconceptions. by battery life I mean life expectancy which is defined as a lose of 80% of rated capacity, hence a battery replacement is recommended

#1 " the iPad batteries are rated for 1000 Full charge/discharge cycles before battery capacity is reduced to 80%. ". This statement is 100% false. I'm challenging Apple and their design engineers to prove this. The best you can ever hope for is 500 +/- 10% cycles for lithium ion polymer batteries and I'm being extremely generous. I evaluate batteries for living, 1000 full charge /discharge cycles are not possible unless ambient temperature or the drain level is manipulated to yield the desired results.

#2 "you fully charge and drain your iPad batteries once a month to calibrate the battery meter". Again false statement. The fact is you should never let your battery approach 0% charge Ever. Every time you let your battery drain, you let the battery cells approach polarity reversal and you drastically reduce its life. Every time you let your battery drain below 80% charge you reduce it's life. Always keep your iPad batteries charged as close to a 100% as possible. if you want to calibrate your battery meter, note what your percent charge is, then hold the the button in the top right corner to turn your iPad off and back on. now note your percent charge. Works every time, go ahead and try it.

Hope this helps.

Posted on Dec 31, 2011 6:49 PM

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Answer 1

Dec 31, 2011 7:00 PM in response to mshahwan

I'll take Apple's advice over some random self important person on the Internet, thank you kindly.

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Answer 2

mshahwan Author

Level 1

4 points

Dec 31, 2011 7:05 PM in response to Johnathan Burger

I'm assuming you work for apple. Hi I'm an electrical engineer. What's your qualifications and what part of what I wrote confuses you?

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Answer 3

Fred-M-

Level 4

2,397 points

Dec 31, 2011 7:05 PM in response to mshahwan

Mshahwan-

#1 - Is there an industry standard that describes how to test the number of charge/discharge cycles before battery capacity is reduced? If not, the number (1000) means whatever Apple wants it to mean!

#2 - Is it possible Apple considered your concern when they designed the low-charge shutdown circuitry? It may be protecting itself by cutting off when the charge is still at a safe level.

So 1000 cycles of 10 hours each would be 10,000 hours. At 80%, that would be 8000 hours. Assuming a linear degradation, a user should expect about 9000 hours of use before noticing the shorter battery life. A new model will be out before then!

Fred

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Answer 4

Dec 31, 2011 7:23 PM in response to mshahwan

It's nice that you're an electrical engineer. And Jonathan, nor myself, or anyone on this forum who spends countless hours each week helping people with their iPads, works for Apple. We'd be fired, if we worked for Apple and posted on this user forum. So, did you design the batteries in the iPad? I didn't think so. Like Jonathan, I'll follow Apples advice. So far, with my devices, Apple has helped me maintain them in just fine working order. My iPhone for example is now almost two years old. My iPhone battery works as well as the day I bought it and I've followed Apple's advice.

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Answer 5

Dec 31, 2011 7:18 PM in response to mshahwan

I am a theoretical physicist, neurosurgeon rock star.

I said so on the Internet and you can't prove I'm not.

Ps.

I understood your post-I don't believe you know what you are talking about since Apple designs their own batteries and has patents and such.

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Answer 6

Philly_Phan

Level 7

20,707 points

Dec 31, 2011 7:21 PM in response to mshahwan

Please provide evidence of your credentials.

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Answer 7

mshahwan Author

Level 1

4 points

Dec 31, 2011 7:24 PM in response to Fred-M-

Hi Fred

#1 IEEE 1725 is one of many but seems to be the dominant standard.

#2 don't think you protect against polarity reversal. The batteries drain even if they are not being used.

#3 batteries don't degrade linearly.

The hole idea is to obviously get you to by the new model. But I would like to enjoy my iPad a little bit longer.

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Answer 8

Dec 31, 2011 7:25 PM in response to mshahwan

I am an electrical engineer, too.

Since you have no idea how much charge is left when the Apple battery meter reads "0%", maybe you should trust that Apple has control over things you do not have access too.

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Answer 9

Dec 31, 2011 7:28 PM in response to mshahwan

It's "whole" not "hole".

Apple has a battery replacement plan-don't need to buy a new anything.

http://www.apple.com/batteries/replacements.html

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Answer 10

mshahwan Author

Level 1

4 points

Dec 31, 2011 7:32 PM in response to Johnathan Burger

Believe it or not even apple has to conform to industry standards when designing batteries. Because these industry standards are built through experience. Lithium ion battery designs are no mystery they have been beaten the death and they are 99.9% identical no matter who designs and builds them.

If you dought my method, dare to test it :)

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Answer 11

mshahwan Author

Level 1

4 points

Dec 31, 2011 7:54 PM in response to Keith Barkley

Hi kieth , Waw what a back lash. This thread is getting out of hand pretty quick. Lots of faithful apple fans.

Well I would love to take apples word for it but my engineering spidy sense is tingling. The thing is even if the meter showed 0 % and there is a safety residual charge of say 5% one of the cells might still approach polarity reversal because it's a weaker cell. Not all cells are created equal.

Jonathan you must be an english major. There is the protection plan that apple offers

"Apple will replace the battery if it drops below 50% of original capacity."

Can you charge and discharge your iPad 500+ plus times in 90 days? This basically says unless the battery is defective from factory , apple is not paying for your battery replacement. Not really very useful in prolonging the life of the battery you already have.

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Answer 12

Dec 31, 2011 8:01 PM in response to mshahwan

Where are you getting the 90 days number?

Stedman

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Answer 13

Dec 31, 2011 8:58 PM in response to mshahwan

Read all of it.

$99 charge if out of warranty, $6.95 for shipping.

Mother was an English teacher before getting Masters in Nursing.

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Answer 14

Fred-M-

Level 4

2,397 points

Jan 1, 2012 9:30 AM in response to mshahwan

Mshahwan-

Doesn't non-linear battery degradation tend to happen later, towards the end of life? If so, assuming it to be linear is pessimistic.

If a single cell failed due to polarity reversal, would that cause the iPad to shut down? A one-cell failure might be sufficient to satisfy Apple's battery warranty.

It seems to me that Apple has almost two years of experience with iPad 1 batteries, plus previous experience with other i-devices and laptop computers. The cost of a warranty is part of the purchase price, so they have an incentive to keep it low to maximize profit.

Fred

(Six munce ago i cudn even spel enjenir. now i are wun)

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Answer 15

mshahwan Author

Level 1

4 points

Jan 1, 2012 12:06 PM in response to Fred-M-

Hi Fred.

Battery degradation starts the moment you start using it. And it's non linear from day one. It's exponential. It's starts nice and slow and then accelerates as you get closer to end of life. People are not getting my point. I'm not worried about the batteries crapping out on you during the first year of ownership, lithium ion polymer batteries are pretty tough and it's unlikely that someone can reach 80% of its capacity within a year, barring a manufacturer defect. I'm talking about the 2nd and 3 rd year. If you maintain the battery properly it should last you 3 years and still hold more than 80% capacity. Replacing batteries is not cheap, I'd like to squeeze every drop of juice out of them.

If one cell goes bad Then your battery is destroyed Becuase it will not be able to output the required voltage. And you won't be able to fully charge the rest of the cells.

Point is fully discharging a lithium ion polymer battery is not a recommended practice if you want to prolong the life expectancy of your batteries. If you have scientific justification or proof of this practice then show me. Otherwise have guts to question why things are done a certain way. If you want to be loyal and obedient user that just does what he/she is told, even if it doesn't make sense, thats fine too.

It's out there to help whom ever has the wisdom to try it.

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