xkcd

While my sentence could be worded more clearly, that's a pretty bad reading of what I said.

My car is valued by KBB at ~6k in it's current state.

That current state includes a battery that was replaced under warranty 6 months ago, and is thus basically a brand-new battery, 9 years left on its warranty and everything.

So if something goes wrong with the battery and it isn't directly your fault: it gets replaced for free. The only 6k being spent is the original 6k on the car as a whole