How can my MacBook detect when the battery is removed or disconnected?

Thank you very much Dan, I cant seem to figure out how the battery sensor would work for the macbook with it being "unplugged".

Thank you for also providing the ifixit link for the replacement battery. I was planning to take a look at the battery prices of authorized apple service centers here in our country but if it comes too expensive, I am planning to buy aftermarket ones (from china), which doesnt seem like a good idea at the moment.

@aahlester - Apple won't fix this system as its vintage!https://support.apple.com/en-us/HT201624|Vintage and obsolete products] which is a nice way of saying spend your money on a new system ;-{

Do be careful where you get the battery make sure its not a fly by night kind of outfit, and one with a good warranty! Focus on a brick and mortar outfit that's been in business for a few years.

@danj I tried checking out the NuPower batteries here and retailers are selling it for almost $200, which is too expensive for me. So I just tried buying an aftermarket one. Customer comments were positive and they did seem satisfied so I gave it a try. I'll leave an update here once I've tried using the batteries just so other guys who are planning to buy cheap batteries would have an idea what to expect.

Thanks again Dan for the very helpful response.

@aahlester - Download CoconutBattery so you can monitor the battery.

Many of these real cheap batteries are failed QC batteries! So be careful!

@danj Would just like to give an update. I tried ordering aftermarket parts online (since ordering from ifixit would be a difficult process because I live in the Philippines.). And as expected, it didnt work. I encountered the common problem where the battery was not able to charge at all. Did all I can to try to make it work but to no avail. I was able to request a refund on the item though and luckily, the person who sold me the product was really accomodating. I'll have to put the project on hold for a while since the refund process is really time consuming.

Thank you by the way for introducing me to coconut battery it is such a useful app especially for me who relies on aftermarket batteries.

Thank you for the helping hand @danj

Cheers!