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Late 2011 model, A1278 / 2.4 GHz i5 or 2.8 GHz i7 processor.

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No Battery recognized and only one battery led indicator always on

Hello all,

I tried to turn on my laptop and it didn’t start, at all by any means, after reading a lot try to and see the causes, I tried the SMC but it didn’t work, I ended opening my laptop and removing the logic board to clean it up, after that My laptop turn on but I noticed it didn’t recognize the battery anymore, I reopened the laptop to verify I didn’t left any cable unplugged but it seems everything is well connected. My laptop still only working with the charger only.

The other weird thing I’m seeing and I have not had luck to find anything about is that one of the battery indicators led in the left side is always on, and by always I mean always even when I turn off the laptop and remove the charger of my laptop. (See Image Below)

As final comment, I also checked the voltages measures in my battery, I haven’t found the schematics for my laptop but I got readings of 12, 5 and 3.3 Volts in my battery, there is one pin that reads 2.5 Volts not sure if is the communication bus because I don’t have the schematics.

I’m looking for advices to fix my laptop, even if it is an old device it works great after a RAM and SSD Upgrade.

Any advice? - Thank you beforehand.

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Update (10/20/2019)

Dan I really appreciate your quick answer. Thanks :)

Tomorrow I will check the module for the battery indicator and will post what I find.

For the battery, thanks for the suggestion, see my screenshot below. Thanks beforehand for the interest on helping me and any comment you may add will be loved.

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Another weird thing I see and I don’t understand is below, coconut says the battery is connected but also that is not connected. Thanks

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Update (11/09/2019)

To anyone can help me :)

I just bought a new battery but not a new battery checker module, I still having my battery issue, my laptop does not recognize it, the battery third indicator led turns green always and my laptop does not find anything about the battery. See attached coconut battery print screen. Any idea someone can guide me in order to fix my laptop?

Thank you guys beforehand.

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Answer this question I have this problem too

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Your battery is freaking out! There is a small micro controller within it which is failing.

Between the two I'd guess this system has liquid damage. Time to replace the battery as well!

How did you clean your logic board? You may have done more harm if you didn't do it correctly.


Anybody else who has an idea/opinion about my problem?

I really want to be sure what to do in order to fix my laptop.

Thanks you all guys!


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Most Helpful Answer

The battery checker switch is likely not popping back so its always pressed. What you’ll want to do is remove the battery and on the side carefully remove the two screws holding the checker module. Once out you can clean the button and make sure its not corroded up, as the LEDs to the left should be lit. You might need to replace the module. MacBook Pro 15" Unibody Late 2011 Battery Replacement

Lets also get a better view on what’s happening here install this gem of an app CoconutBattery take a snapshot and post it here for us see Adding images to an existing question

MacBook Pro 15" Unibody Late 2011 Battery Image


MacBook Pro 15" Unibody Late 2011 Battery Replacement



10 - 45 minutes

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Adding images to an existing question


Very easy

2 - 5 minutes

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Thank you very much again @danj :)

At the beginning I though to replace the battery but wanted to be sure it was the real issue before doing that. I think after upgrading my ram and the SSD that would be the next upgrade but I'm a little concern about where to find a great battery for this, the original battery last 7 years and I'm concern about if I can find a great battery as that one. Do you have any advice Dan?

I'm not sure if for liquid damage you mean that accidentally liquid was spilled my laptop or that the battery has internal liquid damage, but basically there was not an accident any liquid :)

What I did for cleaning was removing dust with a soft tooth brush and cold (well the air was neither warn nor hot) air from a hairdryer. I was thinking to reopen the laptop and use isopropyl alcohol. I would apprecita any advice on this as well.

Thanks again for the interest and time to help me. I really appreciate it.


What can happen is a spill can seep onto the backside of the logic board which is where the SMC logic is located and can also damage the battery.

Follow this guide to inspect the other side of the logic board for staining or corrosion damage MacBook Pro 15" Unibody Late 2011 Logic Board Replacement.

Most of the time using a soft paint brush and a can of can'ed air is all that's needed. If you find something sticky (dried coffee/tea or soft drink) use distilled water with cotton swabs, then going over the area again with 85% or better Isopropyl alcohol as the lower grades often have other junk in them. Do make sure you've let the parts fully dry. I like using a sunny window sill to help warm the parts speeding up the drying.


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