Plugged in and using battery??

[vmachiel]

Hi,

Weird thing was happening, my MBP charger was plugged in but it was still running on the battery. i removed the magsafe to find half the battery drained. Has anyone else ever have this?

 

[snaky69]

Hi,

Weird thing was happening, my MBP charger was plugged in but it was still running on the battery. i removed the magsafe to find half the battery drained. Has anyone else ever have this?

If you are very hard on the computer running very processor and graphics card intensive programs(some games can do this too), the power adapter is not able to provide all the power needed to the computer, and the computer will start draining the battery to compensate.

You're seeing perfectly normal behaviour, nothing to worry about.

 

[dusk007]

It uses the battery for power spikes but half empty is probably something else.
Maybe it just didn't realize it was plugged in. Little bug or not properly adjusted who know. A restart or remove and attach would probably fix it.

 

[windowstomac]

My MBP frequently reports being charged to 97-99% despite being plugged in all day, so perhaps a tiny amount of battery is being used....

 

[vmachiel]

Ok, thanks for the responses. Did a reboot and it's working fine again.

 

[snaky69]

My MBP frequently reports being charged to 97-99% despite being plugged in all day, so perhaps a tiny amount of battery is being used....

The battery controller on the battery charges it to 100%, then lets it trickle down to 95% then back to 100%, it's how it keeps the battery healthy by giving it some exercise and is perfectly normal.

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It uses the battery for power spikes but half empty is probably something else.
Maybe it just didn't realize it was plugged in. Little bug or not properly adjusted who know. A restart or remove and attach would probably fix it.

If said spike is a huge Finite Element Analysis requiring all 4 cores maxed out + the GPU pitching in, said spike can last for a few hours.

 

[GGJstudios]

Weird thing was happening, my MBP charger was plugged in but it was still running on the battery. i removed the magsafe to find half the battery drained. Has anyone else ever have this?

It's possible that during periods of extreme demands on the system, it will draw power from both the AC and the battery. More likely, however, is that the MagSafe adapter wasn't fully connected the entire time, so it was only drawing on battery.

The battery controller on the battery charges it to 100%, then lets it trickle down to 95% then back to 100%, it's how it keeps the battery healthy by giving it some exercise and is perfectly normal.

That's not correct. In fact, they are designed to avoid such short discharges and charges.

Some Apple portable computers (PowerBook G4, iBook, MacBook Pro, MacBook, and MacBook Air) may not show the battery as 100 percent charged in Mac OS X, even when the power adapter is connected.

The battery may appear to stop charging between 93 percent and 99 percent.

This is normal. The batteries used in these computers are designed to avoid short discharge/charge cycles in order to prolong the overall life of the battery.

See the CHARGING section of the following link. This should answer most, if not all, of your battery questions:

Apple Notebook Battery FAQ​