DW-8000 Battery Comes Back to Life

I’ve owned a Korg DW-8000 since 1986, it’s on it’s 3rd battery. Around 2016, I plugged it in after two or so years of non-use and the battery was dead.

In mid-2019, I got around to addressing the issue and bought a new power cord, plugged it in, but still nothing. I left it plugged in, and thought to try it again last week and it powered up.

It’s working great, but it all seems like a fluke. Should I just go ahead and replace the battery now, assuming it will eventually figure out it’s supposed to be dead?

Thank you for any advice/feedback.