MBP with unrecognized battery

August 6, 2009 2:43 AM

Aging MacBook Pro not recognizing its battery. Not under warranty. Is resetting the PMU my next step?

It's a 3-year-old MBP (mfd summer 2006).

Battery icon in Apple Menu is a battery with an "X" inside it. This icon's dropdown menu reports "No batteries available." Disconnecting AC causes instant hard shutdown (so this isn't just battery being wrongly reported as inaccessible).

Some threads I've found suggest resetting the PMU, but Apple's instructions stress several times that this is a last resort. Why? Can the reset process go wrong globally enough to make the MBP unusable? Data loss isn't a concern, but I definitely can't be without my only computer. I also definitely can't afford a new battery.

Should I try the PMU reset or try something else?


----- Some questions you might want answers to, based on my googling so far:

• I'm fully current with system updates and I'm running 10.4.11.

• I've restarted (normally) many times with no change in the battery problem, which has lasted weeks now. I can't pinpoint when it started (or think of a specific reason it would've started). Battery is slightly bulged out (no longer flush with the back of the MBP) and I also don't know when that started to be the case.

• I can't report how many charge cycles the battery has gone through (because all System Profiler says about the battery is "batteries installed: 0"). But this machine has had a pretty desktop-bound life. Prior to this, the battery wasn't holding much of a charge but it certainly held enough that I could sleep the machine, then unplug it, then keep it asleep for a few hours, and then wake it up successfully next time it was plugged into AC (which is all I really care about being able to do).

• My MBP does fall within the date range of the MBP battery replacement program, but that program seems to have ended (?).

posted by kalapierson to computers & internet (12 comments total)

Some threads I've found suggest resetting the PMU, but Apple's instructions stress several times that this is a last resort. Why?

If it's like some other Apple products I remember, that will also reset the "odometer" that keeps track of how many charges are likely left, to help calculate the "time remaining" and percentage estimates. So it can screw up the bookkeeping and give you a battery, possibly, that reports 2 hours remaining when it's really got about 3 minutes.

I don't know if this applies to current MBPs, but it was true in ye olden days of Power-bookes.

As for the battery itself: clean both sides of the connectors with an alcohol swab (and let them dry well) and try again. You can also determine whether it's the battery itself or your MB's ability to charge it by testing the battery in a different MacBook, or a different battery in yours. Obviously, that depends on having access to another.

Replacement batteries are pretty cheap now, especially if you don't mind a short-life used one from eBay.
posted by rokusan at 4:01 AM on August 6

From Apple's website:

You should only reset the SMC if you've tried all of the steps listed here and the computer still isn't working.

1. Force Quit (Option-Command-Escape)
2. Restart (Control-Command-Power)
3. Force Shut Down (press the power button for 10 seconds)

Only perform an SMC reset on the computer if none of the above steps resolved the situation.

I suppose that's what they mean by last resort.
posted by I_pity_the_fool at 4:55 AM on August 6

After 3 years, the battery is probably shot. I think your "next step" is to buy a new battery.
posted by Chocolate Pickle at 5:58 AM on August 6

Resetting the PMU is no big deal, but I guarantee this is a shot battery.

PLEASE DISPOSE OF IT PROPERLY when you get a new one. You can take it to an Apple Store or a radio shack store.
posted by fourcheesemac at 6:18 AM on August 6

Ditto the shot battery. If you ever let the battery run all the way out -- and I mean all the way -- this can happen. Happened to me. New batter is the only thing to do.
posted by pmbuko at 6:45 AM on August 6

Not a guaranteed shot battery at all. This has happened to my MB several times, and only once required a new battery (which is a freebie from Apple regardless of warranty). Resetting the PMU fixed it for me every other time.
posted by roofus at 7:06 AM on August 6

(roofus, you got a free battery replacement from Apple out of warranty?)
posted by kalapierson at 7:53 AM on August 6

Lithium batteries decay with time irrespective of use and charging pattern, and are largely past their useful life at 3 years.
posted by Chocolate Pickle at 9:44 AM on August 6

Update: I've done the PMU (SMC) reset now with no observable effect of any kind.

I got a private message from someone who had similar symptoms and found that replacing the DC-in connection was the solution...
posted by kalapierson at 10:32 AM on August 6

Battery is slightly bulged out (no longer flush with the back of the MBP) and I also don't know when that started to be the case.

A bulging battery seems potentially dangerous because, to me, that suggests a situation where the battery overheated. Lithium batteries do occasionally catch on fire. You should remove the battery promptly. Take the battery and the computer to an Apple store and have them check it out. They can confirm the problem is the battery and they'll pop one in the computer test if it recognizes it and can charge it. Assuming it is the battery at that point you can decide if you want to buy a new one there for $129 or try to source one elsewhere.

Three years is really longer than you can expect to get out of a lithium laptop battery so you got good service out of it. Also, as pmbuko says, you may not be able to charge a completely drained battery.

But please take the battery out ASAP and stop trying to charge it.
posted by 6550 at 12:09 PM on August 6

New batteries are NOT "a freebie from Apple regardless of warranty."

Nthing that this is more than likely a bad battery. Take it to your local Apple Store or authorized dealer and they can verify by putting a known good battery in the unit.
posted by BryanPayne at 12:32 PM on August 6

Thanks for the advice to run it with the battery out. I agree and am now doing that.
posted by kalapierson at 2:04 PM on August 7