Oh they don't, I didn't even notice that haha. There is a slot for it in the box, though. The manual has no kind of "Included" list, so no help either way.
@nelsonm64 - first battery charging result is good:
I took my batteries out just now, after they'd been in about 10 hours. I had not been vaping exclusively on the device for the whole time, but I would say at least 85% of it.
At the point I removed them, the battery indicator was around 50%, and had been there for a couple of hours at least.
On the charger, both showed
3.6V. Unfortunately my Lucv4 only shows one decimal place, so I can't be more accurate than that. But practically every time I've removed batteries on the Waidea (and my IPV4 for that matter) they've showed 0.1 apart.
I believe there's a way of testing battery voltage using a DMM? I have a fairly accurate, 22000 count DMM - if anyone can tell me how to use that to get a two-decimal-place reading of their voltage, I'd be glad and interested to do it.
Given the first result was good, I will now let my second freshly charged pair of Samsung 25Rs drain until Weak Battery before checking again, so that will (hopefully) be in about 24 hours time.