Macbook Pro Unibody 2008 Draining Battery when Shut Down! Model #: A1278

I have found the quality of third party LiON batteries to be very poor even when purchased from a reputable vendor such as OWC. I really don't like or trust third party LiON batteries.

Try an SMC reset.

Make sure no external devices are attached to the laptop.

It is possible your laptop is not completely shutdown. I've seen a number of computers stall out on the shutdown process and appear to be off when in reality they were still running. This can happen even with an SSD installed.

The best way to test is by restarting the laptop and hold down the Option key just after the startup chime so you see the Apple boot picker menu. Perform the SMC reset while at the Apple boot picker menu so you can see the laptop power off and know you triggered the SMC reset. Leave the laptop this way to see if the battery drains as quickly when not in use. I believe this model laptop will remain powered off after the SMC reset, but if it doesn't stay off then Option Boot again, but this time just hold the power button until the laptop powers off.

Another test would be to remove the battery from the laptop when you are not using it to see if the battery drains on its own which would easily indicate a defective battery.

MeeceIT wrote:

Thanks for the advice. How do I perform a SMC Reset? According to this link (https://support.apple.com/en-us/HT201295), it states that I would need to remove the battery, and then press and hold the power button for 5 seconds.

Hmm, I forgot about that, but I thought I used the keyboard sequence (Control + Option + Shift + Power) to perform the SMC reset on those systems as well. Easy way to check is to Option boot the laptop so it is on the Apple boot picker menu. Use the keyboard commands to see if the laptop immediately powers off and the magsafe LED changes colors which would indicate the keys initiated the SMC reset.

Side note - Just found out my battery no longer charges to 100 percent. Stops at 99. Is this a sign the battery is the issue?

No, it is not uncommon. In fact I recall some older Mac laptops would not charge the battery until it dropped below 90%. I've even seen some older laptops stop charging around 72% for some reason even with a good battery. When that happens I had to disconnect the magsafe & reconnect it in order for it to continue charging past 72%.

Also, were would you suggest I purchase a battery?

I always choose Apple's own batteries, but since Apple no longer supports this laptop your best option is probably OWC, but like I said I have gotten defective batteries from them as well. Plus I have seen several recent posts on these forums with reports of people receiving defective batteries from OWC. iFixIt may also be Ok, but OWC would probably be the better option.

Part of the problem is this system is so old that the batteries for it may have been sitting in a warehouse for a long time. If batteries are not properly stored and charged once in a while, the battery can become damaged. It may not be possible to get a good battery for this laptop.