This topic is PHEV-specific. HEV owners don't have an external charging option, and EV owners are likely to have solid reasons for wanting Level 2 charging in their homes. But PHEV owners have to make a decision and the choices are hardly self-evident.
PHEV owners receive a level 1 charger when they purchase their Niro. We can plug it in to standard household electrical outlets, it takes longer to charge our PHEV than level 2 would take, but given that our maximum EV range is 26 miles and we can get a full charge overnight on Level 1, most of us are content with the level 1 charger's performance. Not having to hire an electrician and pay significant sums of money to install level 2 charging equipment reinforces that perspective.
But the owner's manual recommends level 2 and describes the level 1 charger as an "emergency charger". Many of us are concerned about maximizing the lifetime of our PHEV battery, and we're left questioning the owner's manual guidance because conventional wisdom suggests that slow (level 1) charging is likely to be better for battery longevity, but the owner's manual seems to contradict that conventional wisdom.
There are a lot of other threads on this forum that discuss these sane questions. My hope is that this thread will give this specific topic a home for future discussion.
In this post
points out some level 2 advantages, in terms of both time and temperature. It's worth considering if you live in a cold climate, are concerned about charging efficiency/economics, or if your situation would allow you to avoid depleting the charge in your PHEV battery if you can use a level 2 charger, when you would be more likely to (almost) fully deplete it with a level 1 charger. That's because depleting the battery is not great for longevity either, although I think most of us PHEV owners are inclined to do that when exceeding our 26 mile range, because that's kind of the point of owning a PHEV. It would be interesting to see a scientific study on which is worse: depleting or avoiding depletion by fast charging.
Several threads speculate that Kia recommends level 2 not because it's necessarily better for your battery, but because of corporate liability concerns. The thinking seems to be that if you install a level 2 charger, it's going to land on a brand new dedicated circuit in your garage, because not many people have 240 V outlets in their garage and so level 2 likely requires an electrician to install new wiring that conforms to modern electrical codes, but if you use the level 1 "emergency charger", you might plug that in to old, substandard, house wiring and because the level 1 charger pulls a lot of current, if you have crappy or overloaded wiring in your garage, it could lead to a house fire which could lead to a lawsuit against Kia. I don't completely buy that theory, because it's not like the level 1 charger is necessarily pulling more current than is "legal" or "standard". The draw is comparable to a high powered hair dryer, although it's different from a hair dryer in that it runs for hours, rather than minutes. So yeah, if you have crappy garage wiring, that long high current draw could heat up your house wiring and start a fire when a hair dryer would not, but I don't really think that this is the reason why Kia recommends level 2 in the PHEV owner's manual. Which is not to suggest that I know what their real motivation actually is.
Looking forward to reading what others might be thinking on this topic.