Overnight Charging.

It's OK. The phone stops charging when the battery is full. I charge my phone overnight, every night. It is currently 2 1/2 years old and the battery is fine.

No, charging automatically stops when your battery is full. You cannot overcharge.

Charging to 100% overnight is safe but stress the battery. This stress happens to all Lithium batteries technologies charged to 100%.

As overnight charging will always reach 100%, it will reduce the battery life to 300~400 charges, which is the normal expected life

But you can increase the expected battery life. Charging up to 70% will increase the battery life 3~4 time as it reduces the stress. Charging up to 80% double the life.

Overnight charge may reduce the battery life due another effect. When you charge your Iphone and it reaches 100% it will stop, but there is a problem. The radio circuit of IPhone 4 is connected direct to the battery, so even reaching 100% IPhone will discharge the battery with the charger connected. When the battery is discharged a little bit by the radio circuit the charger circuit will start charging again to complete the amount discharged. That will repeat several time during the night reducing the battery expected life.

Some says that after completing the charge IPhone use only the AC/DC adapter. this is not correct, just look at the circuit you will have the real information. Most that say the opposite is just guessing or read from someone guessing, not looked the circuit.

Anyway, 300~400 will give you 2~3 years of normal use which is great.

But if you are a heavy user, it may be worth to charge up to 70~80%.

Probably start charging at 40%~50% and terminating at 70%~80% will give you the best battery life (3~5 times than charging to 100% overnight). Starting charging lower than 40% also stress the battery due increase of temperature during charging process.

Sergio

That's at least the second time you have posted this mumbo jumbo, and it is just as wrong this time as it was the last time.

This is just based on data. If you have data than opinion to present I am ok.

Re: Overnight charging can affect in the iphone 4s battery

Oct 19, 2012 6:18 PM (in response to Monbethjulianne)

Battery life is not linear

Laboratory data of Li-polymer batteries, charging and discharging until they loose 20% of their nominal capacity.

4.3V - 110% charge, battery life 150~250 cycles.

4.2V - 100% charge, battery life 300~500 cycles

4.1V - 90% charge, battery life 600~ 900 cycles.

4.0V - 70% charge, battery life 1200~ 2000 cycles.

3.92V - 50% charge, battery live 2000~4000 cycles.

So for example, if you charge 50% the battery will last ~ 3000 cycles. 100% will last ~ 400 cycles.

New Samsung notebooks are rated to 1500 charges, they charge the batteries up to 80%. To compensate the loss of 20% of capacity they increased from 6 to 8 cells.

Similar happens with satellites where the battery life is more important than capacity as they cannot replace than, so they are not charged fully.

If anyone has any doubt about Iphone 4,continues to use the battery after its complete 100% charging with AC/DC adapter connected, look into RF power regulator MAX8839l. This devices send the regulated power supply to 3G power amplifiers and the only power supply it uses is the Battery. So it keep discharging the battery even with AC/DC connected and battery fully charged. As it discharge the charger turn on again and top up the battery.

This is not my opinion, is just how was designed.

So based on your "facts", my iPhone 4 which is over 2 years old (purchased new in July of 2010) and has been "overnight charged" every day since I bought it (actually worse since it's been in a Mophie Juice Pack Air nearly 100% of the time) it has gone though 700+ 100% charges, so it should have no battery life remaining. According to your "data" the battery only has a life of 300-500 cycles, yet it still holds a nearly 100% charge after close to 800 100% charge cycles (and as I said, it's been in a Mophie Juice Pack Air which keeps the internal battery at 100% charged most of the time). Your "data" and my experience don't agree...

I have a 3GS and bought it new when they came out and that was like 4 years ago. I have charged it overnight pretty much every night since I bought it and the battery is still fine

This data is based on full discharge and charge, which stress more the battery as you heat them. If you don't fully discharge and charge the battery is less stressed so the numbers gets better.

This is also a trick to improve battery life, don't fully discharge the battery to charge as it is also a stress factor.

I looked into many variables and I charge my IPAD2 from 40% to 80%. I use a 2h timer where I plug the AC/DC adapter and leave charging overnight. In the morning it is at ~80%.

I hope the batteries will last more than the product itself.

As I mention this extended battery feature, charging up to 80%, is already implemented in Samsung notebooks, they call it PowerPlus.

Charging at 100 give the best use of battery capacity, but not battery life.

Below copy of their website (By the way, I don't have any Samsung products)

"Keep Your Battery Going with PowerPlus

PowerPlus is a technology offered on Samsung notebooks designed to let you discharge and recharge your laptop battery up to 1,000 times. That’s better than three times the longevity of a standard laptop battery, which typically wears out after 300 cycles and three years of daily use.

Most battery damage occurs when the cells inside are at or near capacity. That’s because batteries get a bit hot under the collar when they max out their charge at 100 percent. This heat causes the delicate structures within to start to break down, which ultimately makes the battery less capable of holding a charge. Eventually capacity drops to the point where the battery won’t hold a charge at all and it has to be replaced.

PowerPlus works to avoid this problem by keeping your battery properly conditioned, thanks to a set of technologies that helps prevent this kind of damage to the delicate electronics inside.

Battery Life Extender

One of the key features of PowerPlus is a simple setting you’ll find on your Samsung laptop called Battery Life Extender. You’ll find Battery Life Extender under the Samsung folder, inside “All Programs” in your Start menu. Here you’ll find the option to either leave your battery in Normal mode (which lets the battery charge to 100 percent of its capacity) or engage the Battery Life Extender mode, which caps the charge at 80 percent.

Battery Life Extender helps keep the battery from overcharging and overheating, which protects it from being damaged. The result is a battery that keeps on going for years. And of course, it’s an option you can turn off or on at any time. If you find you need a little extra juice for a long flight, the setting can always be returned to Normal mode, giving you full access to 100 percent of the battery’s capacity."

NOW I get it. Your selling something. And just blowing smoke to sell it. Everything you say contradicts what Apple says. I'll believe Apple. And I'm going to sign off this thread now because all your doing is spewing nonsense.

I am not selling anything.

For Cellular phones all manufactures design their charging system to maximize battery capacity but not optimum battery longevity. it is a trade off.

But if you are specially interested on battery longevity, you may use what electrical car makers, satellite, etc designers does, charge for maximum battery longevity.