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?New Battery drains too fast .. hmmm


macrumors newbie
Original poster
Sep 25, 2008
Hello ...
I recently bought an old used Macbook Pro; 2012 15", with Retina display, about one month ago
On time of purchase, the battery cycle count was 1 . The seller told me it's a new battery.
Other specs include:

Processor Name: Intel Core i7
Processor Speed: 2.3 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Memory: 8 GB

Since I'm used to work on AC power, I didn't notice any problem. However, when I tried to test the battery, working unplugged, I noticed that the battery drains completely in 2 hours. Worse, I was monitoring the battery, and just noticed that the percentage goes down smoothly from 100% to 50%, then it drops suddenly to 46% then 19%
The battery menu shows at the top : Service Battery

Inspecting the battery it looked neat and clean. is it possible to reset the cycle count of an old battery (i.e. I was cheated)? Could it be a defective battery?

A recent system report on the battery is shown below:
Battery Information:

Model Information:
Serial Number: D86247331K3F9Y2AB
Manufacturer: SMP
Device Name: bq20z45
Pack Lot Code: 0
PCB Lot Code: 0
Firmware Version: 511
Hardware Revision: 000a
Cell Revision: 1150
Charge Information:
Charge Remaining (mAh): 2022
Fully Charged: No
Charging: No
Full Charge Capacity (mAh): 4851
Health Information:
Cycle Count: 7
Condition: Service Battery
Battery Installed: Yes
Amperage (mA): -1836
Voltage (mV): 10726

System Power Settings:

AC Power:
System Sleep Timer (Minutes): 0
Disk Sleep Timer (Minutes): 0
Display Sleep Timer (Minutes): 0
Wake on AC Change: No
Wake on Clamshell Open: Yes
Wake on LAN: Yes
AutoPowerOff Delay: 28800
AutoPowerOff Enabled: 1
DarkWakeBackgroundTasks: 1
Display Sleep Uses Dim: Yes
GPUSwitch: 2
Hibernate Mode: 3
PrioritizeNetworkReachabilityOverSleep: 0
Standby Delay: 4200
Standby Enabled: 1
Battery Power:
System Sleep Timer (Minutes): 10
Disk Sleep Timer (Minutes): 10
Display Sleep Timer (Minutes): 2
Wake on AC Change: No
Wake on Clamshell Open: Yes
AutoPowerOff Delay: 28800
AutoPowerOff Enabled: 1
Current Power Source: Yes
DarkWakeBackgroundTasks: 0
Display Sleep Uses Dim: Yes
GPUSwitch: 2
Hibernate Mode: 3
Reduce Brightness: Yes
Standby Delay: 4200
Standby Enabled: 1


macrumors 65816
Feb 25, 2012
Full Charge Capacity (mAh): 4851
Not quite sure about this one. Shouldn't a brand new MacBook battery for a 15-incher go well over 5500 mAh? My best guess here is that this is a replaced battery, yes, but neither an original one nor really built for this device...
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macrumors 68000
Aug 27, 2015
on the land line mr. smith.
Could be a new battery....but a cheap, bad quality or defective battery. With modern batteries, sadly, we usually get what we pay for. As an example, here is a cheap replacement battery....with low reviews and similar issues to what you describe.

Poor quality, or defective, you have little choice but to replace it. Hopefully with a good quality unit.
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