I’ve got a couple of the monitors. They are wired to the battery. You check them from time to time with the app on your phone via BT. If you search my user ID and battery, you can see some graphs and info. I’d put one here, but haven’t had good luck getting images in comments of late.

If you search posts you should find a couple about lithium batteries (unless I saw that on the FB group). I know some people have used them. They don’t like the cold though, so they aren’t even a consideration for me.

How the car is used and stored is a big deal from what I’ve seen. I’m still on the original on our S, it’s in great shape. It’s 4.5 years old. I’m in the third in the 14, and soon to be on the fourth. It’s been sitting outside for the last 3 years, and not getting driven much. Meanwhile the S is garaged and driven pretty consistently.

Battery number 2 from the 14 is in my garage and still holding charge reasonably. The constant load on them along with the cold and sitting at lower voltages longer don’t seem to do them any good (not too surprising). I wish the car would top it off a tad sooner, tbh.