There is something technical about why the 240 volt HEV has a lithium 12 volt battery and the 360 volt PHEV/BEV has a 12 volt lead acid battery that has not been revealed yet in all my reading about these cars. About the only thing I can conjecture at the moment is the more expensive lithium battery in the HEV makes sense in terms of weight savings that would make less of a difference in the heavier PHEV/BEV.
The PHEV lead acid battery issues are a real eye opener for anyone considering buying one. Type of battery chemistry aside, I see no reason why the battery "reset" button (really just opens a tripped excessive current relay) would not work on the PHEV. For anyone who has had an issue with the PHEV, I might suggest disabling the battery saver option. Having it on results in a much higher vampire current paradoxically (presumptively from running an additional computer to monitor battery status) - which seems like it must be a bug or bad hardware.
The BEVs haven't been around long enough, even in Europe, to know if they suffer from the same issue.
2018 Kia LX HEV Metal Stream with Advanced Tech