Chosen Solution
Hello, I’ve just installed a replacement battery (bought from iFixit) for my mid-2012 MacBook Pro 13inch Unibody. The battery charges up to 84% then jumps to 100%. On disconnecting power lead battery holds 100% for a minute then jumps back down to 84%. I’ve done an SMC reset. No difference. coconutBattery shows the jump in current charge from 5712mAh (fully charged) to 4784mAh (tried uploading images but get a resolution error). Is this a dud battery. Do I need a replacement from iFixit? thanks Mark Update January 23, 2015 I’ll accept @mayer’s answer. After several days testing my MacBookPro seems to be performing normally. The replacement battery seems to be ok. However I do have some reservations. So to recap I reinstalled OSX Mavericks using latest combo update. Did SMC and PRAM reset then did two discharge-recharge cycles. I’m now getting 5-6 hours from a full battery with low-medium use. Time remaining and estimated time to full is generally ok - at least there aren’t any big jumps from say 50% to 100% or crashes from 50% to zero. I’m still getting the impression though that OSX doesn’t have a perfect handle on how much charge is on the battery and neither is coconutBattery. Occasionally the machine won’t reboot after being down to ~30% charge but I’m not sure whether this is because of heavy apps that OSX is trying to reload after previous shutdown. Sleep seems ok and isn;t drastically draining battery. As a rule of thumb how much charge can I expect to see lost during periods of x-amount of sleep (say overnight) or from shutdown to reboot (say overnight)? As a further query the design capacity value from coconutBattery jumps from ~85% to ~96% between and during periods of recharge. Is this normal? thanks all Mark
You may need to reinstall your system and/or update your firmware. Here’s an excellent question on the problem: Erratic “Battery Charging /Not charging” UPDATE put the old battery back in, run Coconut Battery and post your results. Tell us if the battery gives you a red or black X.
