Charging MBA when its 100%

[metamofia89]

For most of my life i don't really bother removing my laptops' batteries when plug in or remove the cord when its 100% and it usually kills the batt charge capabilities within 2 yrs.

If i do this to MBA will it affect the battery?

 

[chehjin]

For most of my life i don't really bother removing my laptops' batteries when plug in or remove the cord when its 100% and it usually kills the batt charge capabilities within 2 yrs.

If i do this to MBA will it affect the battery?

now a days, u use or dun use the battery, it will still slowly deteriorate.

 

[PetPet]

Apple - Batteries

leave it unplugged and allow the battery to drain before plugging it back in.

 

[Arandalo]

I would like to know too. Currently if its 100% I still leave it on power cord when I'm using. Only when I sleeping I leave the power cord unplugged to prevent charging overnight.

 

[HahaHassan]

best is not to charge when using, and after charging it full, unplug it. My macbook air battery life used to last twice as long. I've been leaving the power cord while charging and after its full. But thats after using for 3++ years with 300+ charge cycles already, so may be just the battery dying.

Better safe than sorry.

 

[chehjin]

best is not to charge when using, and after charging it full, unplug it. My macbook air battery life used to last twice as long. I've been leaving the power cord while charging and after its full. But thats after using for 3++ years with 300+ charge cycles already, so may be just the battery dying.

Better safe than sorry.

actually for the li-on battery, the more you use it, the more wear and tear it will experience.

meaning by keep using it then charging, the battery actually dun last as long.

but i dun think it is a significant difference at all.

use ur laptop to ur convenience, thats what I feel is best.

 

[davidktw]

best is not to charge when using, and after charging it full, unplug it. My macbook air battery life used to last twice as long. I've been leaving the power cord while charging and after its full. But thats after using for 3++ years with 300+ charge cycles already, so may be just the battery dying.

Better safe than sorry.

No it doesn't work this way. When the Lithium "Hybrid" Polymer, not Ion cells are charged, power supply to the equipment is another circuit. It is not as if the charger to charging the battery and the equipment is consuming from the battery at the same time. It don't work this way since th incoming voltage from the charger will be at 4.2V per cell. You can't have current flowing into the cells and have the current also flowing out the cells at the same time.

Battery will degrade regardless you charge it or not, that's the technology for Lithium based battery. It is even more pronounce for Lithium Hybrid Polymer, which is what Apple laptops are using. Older laptops uses Lithium Ion which are more durable. Lithium Hybrid polymer are chosen for their higher discharge rate and also their flexibility to shape into various dimensions.

However the more your discharge and charge (one full cycle) of your cells the faster it degrade, that's the usual wear and tear imposed on the chemical. Basically the polymer instead crystallise and inhibit the flow of ions within the cells.

Leaving your power cord to your system will not cause your battery to degrade or over charge. Lithium Ions and Polymer are not your usual NiMH or NiCD, you can't overcharge it. It will bloat unusually and either catches fire or burst into flames. That's why all Lithium based batteries require sophisticated Battery Management System(BMS) to ensure no overcharge or over consumed. Lithium battery are charged at 4.2V constantly. Full current is pump into it until towards the end where trickling charge is used. It's different from charging other batteries type using elevated voltage over time. Lithium Based battery must not discharge below 3V or the chemical will go into an irreversible state and can't be charged. The nominal voltage is 3.7V after charged.

 

[limpe84]

For most of my life i don't really bother removing my laptops' batteries when plug in or remove the cord when its 100% and it usually kills the batt charge capabilities within 2 yrs.

If i do this to MBA will it affect the battery?

In the long run, if you keep it plugged in constantly, it will definitely have some effect.

But so long as you unplug it from time to time and let it run on battery power, should be okay. Otherwise, concepts like the thunderbolt display won't exist (where you dock your laptop and leave it charging all day).

 

[davidktw]

In the long run, if you keep it plugged in constantly, it will definitely have some effect.

But so long as you unplug it from time to time and let it run on battery power, should be okay. Otherwise, concepts like the thunderbolt display won't exist (where you dock your laptop and leave it charging all day).

What kind of effect are you referring to ? How does thunderbolt display comes into picture on this battery topic ?

Even if you plug in constantly, the charger will not just go into charging mode on the battery even if the battery deplete a little over time. It must fall below a threshold before the charging process will set in. Such technique to prevent unnecessary charging is also found in Windows laptop such as Sony.

In fact as you unplug the battery and let it discharge naturally or you consume it by using the battery, you are also in fact consuming the charge cycles as accordingly. There is really little differences between you plug in and you deliberately discharge and charge it.

Next is the 100% as we see on the battery status is not a good reflection of the battery health. It's just a reflection on what is the upper bound and where is the lower bound. Some guides will encourage end-users to periodically discharge the battery fully (shutdown by the BMS) and charge it back again. Such an act actually doesn't protect the battery from its wear and tear, it is only educating the BMS to understand the bounds of the cells and hence set the 100% mark and the 0% mark to the right voltage level.

There are other issues such as balancing the cells across the whole battery unit which are also settle internally by the BMS.

 

[chenaz]

i have to agree with david.

he is right.

for lit battery. u should plug in and let it charge as frequent as possible.
because when it hits 100%. ur macbook is actually not charging. the power will be cut from battery and change to power core.

u can go to preference/system info and look for power. u can see that 100% and not charging.the more u use battery power. the faster the battery life drop as u are consuming battery cycle.

 

[metamofia89]

Soooo in layman's term, i can keep the power supply connected to my MBA even when status is 100% (green lite on magsafe 2)?

 

[davidktw]

Soooo in layman's term, i can keep the power supply connected to my MBA even when status is 100% (green lite on magsafe 2)?

Yes. No charging will happen when the LED is green on the connector. The BMS will not charge even a slight bit when the battery is full.