MacBook Pro 15 not running off battery

I'm hoping someone can help me track down this problem. I have an Early 2008 15" MacBook Pro. I replaced the battery about a year ago. It has been working fine until recently. It started running hotter and hotter. Once it got so hot it started getting that "fried electronic" smell. I shut it down and let it cool off. It still work. A few days later, maybe a week later, the battery suddenly stopped "working". That is to say that it would no longer run off battery. When plugged in, the computer runs normally. It doesn't get hot any longer either. I run iStat and the battery stats all show the expected info: 94% health, 43 charges, 92% charged. I've tried the resetting PRAM and SMC. I also found some firmware patches for the batteries, but the instructions don't match. I'm running Lion.

I'm wondering if I have a bad battery, bad board somewhere. Anyone have any ideas or suggestions? This is my first Mac and I love it.

Burnt electronics smell pretty much says it right there unfortunately. If the computer runs normally on the power cable then you just got a faulty battery. Probably fried the cells so it no longer accepts a charge. I would check and see if your still under warranty and get that baby switched out.

Yeah, I'd would normally agree. Yes, something bad happened. When I take the battery out, the mac shuts down. Guessing that is normal. Pressing the button on the battery shows full charge also.

The location where it got hot is toward the hinge on the bottom. That is away from the battery and the battery never gets hot. Not sure if that helps... Wondering if it could be the charging circuit...

RhinoMac said:

Yeah, I'd would normally agree. Yes, something bad happened. When I take the battery out, the mac shuts down. Guessing that is normal. Pressing the button on the battery shows full charge also.

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Yes this is completely normal, the battery acts as part of the circuit like you said. The computer cant operate without the battery in. Yeah the area you mentioned that gets hot is also normal. try to keep the machine off beds, blankets etc and others areas that serve as a insulator for heat. I personally put a book on my lap if I'm sitting on the couch or something like that.
Question: do you ever hear your fans go on when using the computer?

Um, the fan does come on. I've been backing up with TimeMachine over wireless today. The laptop has been sitting on a table. I just noticed that iStat is not not reporting battery info and the Enclosure Base no longer shows a temp. I do hear the fan, at least from the right side.

ok not to worry, i was just asking to see if maybe your fans weren't triggering. If you hear them then your all good. Backing up is the smartest thing you can do. Your problem is most likely just a simple batter switch, but with computers it never hurts to back up! Definitely check with the company you purchased the battery with and see about an exchange. From the sound if it the rest of your machine is operating exactly how it should.

Out of curiosity, is there some kind of diagnostic program that will check the hardware? Help identify where a problem might be, if any?

RhinoMac said:

Out of curiosity, is there some kind of diagnostic program that will check the hardware? Help identify where a problem might be, if any?

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Absolutely, just shut down the machine and when as soon as you power it back on press and hold the " D " key and that should bring up the apple hardware test.