Released June 2012, Model A1278. Intel processor with Turbo Boost, Up to 512 MB DDR5 Video RAM

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New replacement MacBook Pro battery discharging erratically

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

Answered! View the answer I have this problem too

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What was happening with the old battery?

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Had service warning on old battery

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Chosen Solution

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.

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OK thanks. I'll try PRAM reset and SMC reset again, then complete discharge/recharge cycles and see what the result is.

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I'll reinstall old battery and post coconut results if my first attempted solutions don't work.

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@mayer - Went through 1 full discharge/recharge cycle. Following this the battery discharged as expected from 100% without any jumps. However, MacBookPro on standby still drained battery as though awake. I then performed an SMC reset and PRAM reset. Battery use now *seems* to be functioning normally.

Thanks for your help

One further question. On coconutBattery the design capacity reading has jumped from 99% (first start-up after battery install), to 96% (after discharge/charge cycle), to 97.3% (after SMC/PRAm reset), to 96.3% (after a test period of sleep). Is this significant? OSX Battery status still good, operating temperature 25.6degC, discharging 12 Watts at current low usage.

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wait. Still not good. Crashed 100% to 50% just now. hmmm

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You accepted my answer, did the problem rectify itself?

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mruddy73 will be eternally grateful.
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