Battery percentage not increasing

Greetings,

I bought this Macbook about 5 years ago. Have never replaced the battery. No physical or water damage has occurred.

When I updated to Mojave, the laptop gave me a “Service Battery” message. I checked my battery cycle count and it was around 300, so I ignored the message. The laptop worked fine for a few months without issues.

The situation today is as follows: the battery percentage no longer goes up. It is either stuck on a particular percentage when it’s connected to power, or the percentage goes down when I disconnect it from power. But the battery never actually charges. In ‘System Information’ the Mac recognizes that the AC charger is connected, but it says it is not charging the laptop.

This has happened to me a couple of days before. After restarting the Mac, it fixed itself.

Today this happened again, I tried to restart, reset the SMC, and update the OS to the latest version, but to no avail.

Online, I read recalibrating the battery might fix the issue. However, I fear that if I drain the battery to 0, the Mac won’t open again. There’s also no way for me to get it back up to 100% as it currently stands.

Does anyone have any ideas? Or must the battery be replaced (despite the low cycle count)?

Thank you in advance!