Overcharging Laptops reduces battery life?

[Koshur]

Hi

I want to know if i keep the charge plugged in even after its 100% charged, would it reduce my battery life? Is there a mechanism that when the battery is full charged it automatically works on AC instead charging the battery?

[Astra.Xtreme]

Usually when the battery is fully charged, it will run on AC. The way to check is to hover over the battery icon in the lower right corner and see if it says:

"__% available (plugged in, not charging)"

If it says that, then it's running on AC.

[Mindovermaster Moderator]

Most new laptops, circa 2008-9, will stop charging the battery when it is fully charged. It is best to drain the battery until it has critical battery life, and fully charge it.

[giantpotato]

It is best to drain the battery until it has critical battery life, and fully charge it.

That's not true at all. In fact the opposite is true. You only had to do that with Ni-Cad batteries because they had a memory effect. Charge-discharge cycles reduce the life of lithium batteries.

[Brandon Live Veteran]

That's not true at all. In fact the opposite is true. You only had to do that with Ni-Cad batteries because they had a memory effect. Charge-discharge cycles reduce the life of lithium batteries.

Correct. On modern laptops, you're best topping it off whenever is convenient.

[Mindovermaster Moderator]

Isn't it that when the battery is on 80% then you charge it, will hurt the battery's life span? I mean, if you do it again, again, and again? But charging on low battery to full will last longer? This is what I understand of it. Not that you can overcharge it.

[Astra.Xtreme]

Isn't it that when the battery is on 80% then you charge it, will hurt the battery's life span? I mean, if you do it again, again, and again? But charging on low battery to full will last longer? This is what I understand of it. Not that you can overcharge it.

There's some dispute about that regarding Lithium Ion batteries. Some people think that if you only do partial charges on Li-Ion batteries, something called "digital memory" can occur which basically means the power gauge on the PC or device won't be as accurate over time. They say that if you completely drain the battery and then recharge it, it will re-calibrate the gauge.

I'm not too sure there is any proof that this occurs though.

[HawkMan]

There is no digital memory on modern lithium batteries. in fact modern lithium batteries on laptops include a balanced charger(hence why it has more than 2 plugs, the rest are for the balancer). this keeps all cells balanced and makes sure that the cells are used sequentially, or rather evenly depleted, so that one cells doesn't burn out before the others.

Lithium batteries today, depending on technology used lasts for ~300-600, ~900 or ~1200 cycles.Samsung claim they where first to have the 900 and 1200 cycle batteries. but at least a few others including samsung now have the long life batteries with over 1200 cycles.

This is also why you never deplete them, because it uses up a full cycle. that and the fact that if you empty it, and you forget about it, you run the risk of actually completely depleting it. and a lithium battery that goes completely dead literally dies. it'll never charge again, and the chemical stuff that's supposed to happen, stops happening and it's dead.

and no you can't overcharge a lithium battery. if you could you would have an explosion and lithium batteries have a energy density that is actually higher than that of TNT. luckily they generally don't discharge it in quite the same way, but they blow up hard when they do, even small ones are dangerous. a laptop battery is REALLY dangerous.

[Koshur]

There is no digital memory on modern lithium batteries. in fact modern lithium batteries on laptops include a balanced charger(hence why it has more than 2 plugs, the rest are for the balancer). this keeps all cells balanced and makes sure that the cells are used sequentially, or rather evenly depleted, so that one cells doesn't burn out before the others.

Lithium batteries today, depending on technology used lasts for ~300-600, ~900 or ~1200 cycles.Samsung claim they where first to have the 900 and 1200 cycle batteries. but at least a few others including samsung now have the long life batteries with over 1200 cycles.

This is also why you never deplete them, because it uses up a full cycle. that and the fact that if you empty it, and you forget about it, you run the risk of actually completely depleting it. and a lithium battery that goes completely dead literally dies. it'll never charge again, and the chemical stuff that's supposed to happen, stops happening and it's dead.

and no you can't overcharge a lithium battery. if you could you would have an explosion and lithium batteries have a energy density that is actually higher than that of TNT. luckily they generally don't discharge it in quite the same way, but they blow up hard when they do, even small ones are dangerous. a laptop battery is REALLY dangerous.

Mine has exact 300 cycles. I checked it with the HP battery test utility. And i have used up my 20 cycles so far. In fact what i now do is that, once i know i will be on consistent charge, i remove the battery and keep it on direct AC, since i have power backup at office no that is not an issue but at home that becomes a bit inconvenient.

Isn't it that when the battery is on 80% then you charge it, will hurt the battery's life span? I mean, if you do it again, again, and again? But charging on low battery to full will last longer? This is what I understand of it. Not that you can overcharge it.

Exactly thats what i have read too so far. and i only charge when the battery is drained full. Mine is a li-ion battery 6 cell.

Usually when the battery is fully charged, it will run on AC. The way to check is to hover over the battery icon in the lower right corner and see if it says:

"__% available (plugged in, not charging)"

If it says that, then it's running on AC.

Thanks for this tip, will check this one. I have HP Probook 4530s i7quadcore, 2630QM, i am not sure whether this model has automatic switching to AC power when fully charged.

[AWilliams87]

Most new laptops, circa 2008-9, will stop charging the battery when it is fully charged. It is best to drain the battery until it has critical battery life, and fully charge it.

No it isn't.

[DrJohnSmitherson]

Exactly thats what i have read too so far. and i only charge when the battery is drained full. Mine is a li-ion battery 6 cell.

You're ruining your battery. Keep it at 100% as much as you can.

[Denis W. Veteran]

Taking a rough guess here, but if the battery is roughly between 95-100% charged, if you plug it in either a) the battery won't charge, or b) the battery controller will report the battery as full, hence no charging. A full drain and charge cycle is useful perhaps once a month just to keep the battery meter accurate - which is useful for cases where a worn battery may suddenly go from 40% to critical level.

What does kill batteries are hot laptop undersides.

[Koshur]

How would i know that i have the battery controller that reports the battery as full and switches to AC power?. Or it is there by default in every battery or every laptop made. mine is a new one. just a year older.

[Mindovermaster Moderator]

No it isn't.

Care to explain yourself?

[HawkMan]

How would i know that i have the battery controller that reports the battery as full and switches to AC power?. Or it is there by default in every battery or every laptop made. mine is a new one. just a year older.

Both windows and the lights on your laptop indicate whether it's just using AC power or using AC power AND charging.

Care to explain yourself?

Both I and others already explained why it's nto best to drain and charge the battery(or cycle it as it's called) on any laptop made after 2006 at least.

[Mando]

I play safe and remove my battery charged as i rarely use it away from a power socket these days (if i need to be that mobile I have my phablet).

I see laptop batteries lasting like 12-18months @work which are left in and powered up all day via AC before lasting for 30mins (at best) away from power. I believe heat also has a negative effect on performance of the battery in charge/discharge could explain the performance reduction being left plugged in all the time. Either way both are removed when battery is not there :p

my X201S @work has its battery removed until needed and its 24months+ old, still gives me maximum duration when fitted, said it all to me tbh.

[Astra.Xtreme]

How would i know that i have the battery controller that reports the battery as full and switches to AC power?. Or it is there by default in every battery or every laptop made. mine is a new one. just a year older.

Honestly, any laptop that was made in the last 5-8 years will definitely have the auto switch for AC power.

[Mindovermaster Moderator]

Both I and others already explained why it's nto best to drain and charge the battery(or cycle it as it's called) on any laptop made after 2006 at least.

And yet, it was explained above by other members, exactly what I was talking about. So I am confused..

I wanted his opinion, not yours or anybody else's.

[Draconian Guppy]

How to Prolong Lithium-based Batteries

The lithium-ion battery works on ion movement between the positive and negative electrodes. In theory such a mechanism should work forever, but cycling, elevated temperature and aging decrease the performance over time. Since batteries are used in demanding environmental conditions, manufacturers take a conservative approach and specify the life of most Li-ion between 300 and 500 discharge/charge cycles.

Counting cycles is not conclusive because a discharge may vary in depth and there are no clearly defined standards of what constitutes a cycle. Read more about

What Constitutes a Discharge Cycle?. In lieu of cycle count, some batteries in industrial instruments are date-stamped, but this method is not reliable either because it ignores environmental conditions. A battery may fail within the allotted time due to heavy use or unfavorable temperature conditions, but most quality packs will last considerably longer than what the stamp indicates.

The performance of a battery is measured in capacity, a leading health indicator. Internal resistance and self-discharge also play a role but with modern Li-ion these carry lower significance in predicting the end-of-battery-life. Figure 1 illustrates the capacity drop of 11 Li-polymer batteries that have been cycled at a Cadex laboratory. The 1500mAh pouch cells for smartphones were first charged at a current of 1500mA (1C) to 4.20V/cell and allowed to saturate to 0.05C (75mA) as part of the full charge procedure. The batteries were then discharged at 1500mA to 3.0V/cell, and the cycle was repeated.

Continued AT

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

[+Warwagon MVC]

[Shadrack]

I have always heard that it is best to discharge down to a 5% or so and then do a full charge periodically to keep the battery healthy. But some people seem to disagree that that will do diddly squat and the idea of that is left behind from the previous NiCad rechargeable technology.

Things that are mostly agreed upon are:

* Don't ever, ever, ever let a lithium ion batter drain completely. Once it is drained completely it is probably ruined.

* Charging a battery in a hot environment will significantly diminish the battery's capacity

[Roger H. Veteran]

Definitely don't drain the battery completely. That's first rule.

Actually 40-80% is perfect as 100% constantly involves internal battery heat as well (all the cells full loaded with no room to expand due to heat changes).

My advice has always been to just forget about it as the battery will ALWAYS eventually die. It is a consumable item so as long as it last a good 2yrs you got your money's worth :)

[Koshur]

Kool. Thanks for valuable insights on this folks.. Plugged IN from now on...For the heat, ive got a cooler master U2 and its cuts down the temp...