Macbook Air battery issues

If you reset the SMC and it fixed the issue then that was the problem. If the problem re-appears again then it's probably worth making a Genius Bar appointment to have the battery examined. They have some diagnostic software that's pretty good about identifying battery issues. Also, third party applications such as Coconut Battery can also give you some additional battery insight. As it's a free and harmless app, it wouldn't be terrible to download that and see what that says about your battery for a second opinion.

It's unlikely to be a software issue (OS related) if there's been no changes or modifications to the OS. When jumping releases (such as moving to Lion from Snow Leopard) it's not all that uncommon to get different reporting values on your battery but I can't see justifying an OS upgrade to troubleshoot your battery.

Monitor it over the next week and let it discharge/recharge a couple of times to see what happens and then troubleshoot from there.

Truthfully it's difficult to pinpoint those specifics. An archive & reinstall of the OS would eliminate the OS and software from the equation. It's quick and easy enough to do if you wanted to give that a go. It's unlikely a firmware issue and there's no battery board on the MacBook Air. The battery plugs directly into the logic board so there's only three components to the hardware equation:

1.) Battery

2.) Cable

3.) Logic board

The MacBook Air model you have is rated to maintain 80% of it's original full charge capacity at 300 cycles, you're a 152 cycles over that. I suspect what you might have is a near depleted battery that's causing inaccurate readings on the computer side of things. That'd explain why the charge capacity is bouncing all over the place, it's not terribly uncommon for a dying/depleted battery to display wildly inaccurate statistics.

You can get used/refurbished batteries from places like the one I've linked below -

http://www.powerbookmedic.com/Macbook-Air-Battery-A1245-Replacement-p-17206.html

I'd definitely be careful digging through eBay and such looking for batteries. Spending $40-75 on a battery that might last you a few months doesn't seem like a worthwhile investment.

I'd say the next step, in the interest of being thorough, would be to take your machine in for a battery diagnostic at the Genius Bar.

JasonFear wrote:

The MacBook Air model you have is rated to maintain 80% of it's original full charge capacity at 300 cycles, you're a 152 cycles over that. I suspect what you might have is a near depleted battery that's causing inaccurate readings on the computer side of things. That'd explain why the charge capacity is bouncing all over the place, it's not terribly uncommon for a dying/depleted battery to display wildly inaccurate statistics.

Pretty much a repeat of what I proposed earlier. Depleted batteries do weird things, wildly and unannounced. One minute it works fine and the next it's dead. Sometimes when a battery dies it flat out won't work, even worse somedays a dead battery will prevent the machine from the booting giving the user the impression of a far more serious problem when in reality it's just a bad battery.

An appointment at the Genius Bar is free, it'll take you less than 10 minutes to perform a battery diagnostic and you'll get an official answer rather than speculation from someone like myself. At that point you can evaluate if you need to purchase a new battery and then how much you're willing to spend.