PCWorld Forums: Apple 'must Fix' Ipad Battery Issue, Study Warns - PCWorld Forums

▶ Why does charging continue after it has reached 100%?

100% battery level does not mean that your battery has been fully charged. To maximize the charge capacity, about another 40~80min is needed from 100% to full charged. If the battery has been aged, more time is needed for this process.

Sigh... another tempest in a teapot?

First, we need to determine if Dr Raymond Soneira is just another hit *****, or has legitimate concerns. Good luck with that.

Does Apple really say that not taking your device off the charger as soon as it reads 100% charge will damage the battery. I guess idiots like me that have gotten 4+ years out of their batteries with overnight charging are living on borrowed time!

If the charging circuit isn't smart enough to shut off the charge after it reaches the real 100% there is a real problem here. But it also doesn't sound like that is an issue if the wattage being used drops from 10W after it reaches its real full charge. Apple's comment makes no sense.

djdjohnson, on 26 March 2012 - 08:19 AM, said:

If you watch the report it's not really Apple making comment, it's a reporter paraphrasing what Apple allegedly said. I think we all know what happens when business reporters start paraphrasing technical issues.

As far as I can tell from a couple of hours research, this is pretty much standard procedure for Li-ion batteries.

iPad Battery Allegations Unwarranted
By Lex Friedman, Macworld Mar 26, 2012 1:49 pm

Your new iPad's battery is fine. Despite some media reports suggesting that Apple's newest tablet suffers from a pair of battery-related issues, --Macworld's own research concludes that the third-generation iPad's battery works as designed, and that customers needn't fear harming the battery by over-charging it.

Dr. Raymond Soneira of DisplayMate Technologies first sounded an alarm about the new iPad's battery because he believed that it wrongfully indicated its battery was 100 percent charged when in fact it was closer to 90 percent full. He wrote that if you unplugged your charging iPad at the first moment the battery meter ticked over to 100 percent, "you get 1.2 hours less running time."

But worse still, Soneira further alleged that Apple says leaving your iPad plugged in for too long--when you wanted to, say, top off the battery--could "harm the longevity of the battery."

It's unclear where Soneira's Apple-attributed quote about overcharging the battery harming its longevity comes from. Macworld has found no statements from Apple to any press organization on the subject, and the company declined to comment for this story. All references to such a claim seem to trace back to Soneira's report, or CNBC's coverage of same. And Apple's own guide about charging the iPad's battery makes no reference to an over-charging risk.

Carl Howe, the vice president for data sciences research for mobile-focused market research company The Yankee Group, told Macworld that "There is no damage caused [to the iPad's battery] by leaving it plugged in. ... There's a charging circuit that makes sure that doesn't happen." ...

...That charging slowdown is referred to as trickle-charge mode--"it's like trickling in the water from the pitcher, to make sure you don't go over the lip of the battery," Howe explained. In fact, that trickle charge mode explains Soneira's other concern regarding how full the battery is when the new iPad first reads 100 percent. Howe agrees that, at that point, the battery can indeed get fuller, but says that's not a problem. "The capacity that [Apple is] advertising is based on when the iPad first says 100 percent--everything you get over and beyond that at the trickle charge stage is just kind of gravy....

...That means you can safely plug in your iPad at bedtime; even if the battery meter hits 100 percent at midnight, it's no problem for your tablet to keep on charging until the rooster crows. The new iPad boasts the same 10-hour battery life that the previous two iPads claimed, though it needs a bigger battery to pull that off--specifically, a 42.5 watt-hour battery, compared to the iPad 2's 25 watt-hour model. That larger battery unsurprisingly takes longer to charge completely than the iPad 2's.

If the battery indicator is showing the battery is charged and it stops charging, but the battery isn't fully charged, even tho it isn't a problem per se, shouldn't Apple just make sure its reasonably correct?

If we are going to lose 1.2 hours of usage I dont see that as being a big deal; unless you plan to be away from a charging source of more than 10hrs.

If the battery indicator is showing the battery is charged and it stops charging, but the battery isn't fully charged, even tho it isn't a problem per se, shouldn't Apple just make sure its reasonably correct?
If we are going to lose 1.2 hours of usage I dont see that as being a big deal; unless you plan to be away from a charging source of more than 10hrs.

Avoiding full charge has benefits, and some manufacturers set the charge threshold lower on purpose to prolong battery life.
http://batteryuniver...m_ion_batteries

So basically what they are saying its, a car has a 10 gallon tank, you put 10 gallons in it to get a "full tank" which is also indicated as such on the gauge.

how ever the iPad users are basically getting those extra two gallons of gas into their tank.

which ends up leaking because gas expands when it gets hot.

The battery charge indicator on all mobile devices is based on a mathematical model of the charge rates, discharge rates, and recent discharge history of the battery. It uses this information to estimate how much running time is left. It's actually rather difficult to do because most batteries degrade slowly as they discharge and then tend to surprise with a precipitous decline near the end. Note that batteries are based on complex chemistry so there is no practical way to measure the charge level “in hardware.”

While Apple’s remark (As reported by Jon Fortt of CNBC: "Apple is saying... if you charge it more than [when the battery indicator reads 100%], you could actually harm the longevity of the battery.") might apply to recharging dumb battery operated toys, the new iPad is a very sophisticated and expensive computer device that is fully capable of properly controlling and managing its own (rudimentary) battery charging process. Perhaps Apple should instead graciously accept my interpretation and rescind their own remarks, which sound like very poorly thought out damage control. Otherwise they need to immediately fix the iPad battery charging algorithm or they may be held responsible for replacing all iPad batteries. Which one will it be?

Apple needs to immediately fix the new iPad’s battery charging algorithm, or it may have to replace batteries for all users, a study by DisplayMate Technologies warns. The new iPad's battery needs an extra hour of charge after it shows it is fully juiced in order to get the maximum life on a charge. But this could damage the longevity of the battery, Apple said, so what are users of the new iPad meant to do?