battery going bad?

[beedoola]

I got 48% battery left and the time left is stated as "39 minutes"

I'm on a early 2011 13'' MBP. 2.7 i7, 8gb ram.

Do I need a new battery?

Here are the battery/power specs:

Battery Information:


Firmware Version: 201
Hardware Revision: 000a
Cell Revision: 165
Charge Information:
Charge Remaining (mAh): 2305
Fully Charged: No
Charging: No
Full Charge Capacity (mAh): 5002
Health Information:
Cycle Count: 249
Condition: Normal
Battery Installed: Yes
Amperage (mA): -1285
Voltage (mV): 11172

System Power Settings:

AC Power:
System Sleep Timer (Minutes): 162
Disk Sleep Timer (Minutes): 10
Display Sleep Timer (Minutes): 143
Wake on AC Change: No
Wake on Clamshell Open: Yes
Wake on LAN: Yes
Display Sleep Uses Dim: Yes
PrioritizeNetworkReachabilityOverSleep: 0
RestartAfterKernelPanic: 157680000
Standby Delay: 4200
Standby Enabled: 0
Battery Power:
System Sleep Timer (Minutes): 60
Disk Sleep Timer (Minutes): 10
Display Sleep Timer (Minutes): 60
Wake on AC Change: No
Wake on Clamshell Open: Yes
Current Power Source: Yes
Display Sleep Uses Dim: No
Reduce Brightness: No
RestartAfterKernelPanic: 157680000
Standby Delay: 4200
Standby Enabled: 0

Hardware Configuration:

UPS Installed: No

AC Charger Information:

Connected: No
Charging: No

 

[GGJstudios]

I got 48% battery left and the time left is stated as "39 minutes"

I'm on a early 2011 13'' MBP. 2.7 i7, 8gb ram.

Do I need a new battery?

No, the 48% is how much charge you have remaining, not your battery health. You simply need to recharge it.

This should answer most, if not all, of your battery/charging questions:

Apple Notebook Battery FAQ​

 

[beedoola]

No, the 48% is how much charge you have remaining, not your battery health. You simply need to recharge it.

This should answer most, if not all, of your battery/charging questions:

Apple Notebook Battery FAQ​

yes, I'm aware of that. What I meant was: is the time duration right with regard to how much charge is remaining. My friend has an older 13'' MPB with a Dual Core and she had maybe 60% remaining with a time quote of 4hrs left.

now mine has gone back up - at least in terms of time: 40% charge remaining with 1:34mins. No backlit keyboard on..

 

[leftywamumonkey]

Have you calibrated your battery in the last few months?

 

[GGJstudios]

yes, I'm aware of that. What I meant was: is the time duration right with regard to how much charge is remaining. My friend has an older 13'' MPB with a Dual Core and she had maybe 60% remaining with a time quote of 4hrs left.

now mine has gone back up - at least in terms of time: 40% charge remaining with 1:34mins. No backlit keyboard on..

From the BATTERY LIFE FROM A CHARGE section of the Battery FAQ:

Your "time remaining" indication is an ever-changing estimate, based on the current workload of your system. It will fluctuate up and down from minute to minute as your power demands change. It is not perfectly accurate, but only an estimate.

Have you calibrated your battery in the last few months?

The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries in older Apple notebooks.

 

[sweetbrat]

The time remaining varies wildly up and down depending on what you're doing. If I run something using Flash, my time remaining goes down by at least half. When I turn Flash off, it goes back up. It's just a quick snapshot based on your current workload, so you can't compare it with anyone else's computer.