I have a 24 PHEV and I made the observation in a few posts a while back that in moderate temperatures, the ICE often turns on, and that I seriously DO NOT believe it is to provide heat because when it actually does get cold, and I mean Canada cold, well below zero, I can always drive around entirely on battery and PTC cabin heat and the ICE NEVER turns on unless I either accidentally overdo the accelerator, I run out of battery or I intentionally switch to hybrid mode..

The ICE turning on seems to only be at moderate temperatures where neither heat nor AC would normally need the extra power from gasoline combustion... I suspect it is probably some idiosyncracy of Kia/Hyundai ECM programming... Someone probably forgot a negative in a temperature formula or something and I typical Kia ineptness, this was not caught in code review...

 

Well, using this morning as an example. It was 59F outside, and the HVAC was set on 72. So I wouldn't be surprised if it was calling for a little heat. But the PTC heater should be able to handle that amount of heat easily. I just don't feel the PTC is even being used.

 

The behavior c_4 describes make me wonder if the PTC is only activated if the ambient air temperature is below a set point.

 

Certainly possible, but counter-intuitive how I would expect an aux heater to work. Let it take the heating loads when the temps on only moderately cool, and use the ICE when it's significantly cooler, and the engine is more efficient for providing significant levels of heating. I've emailed my dealer's service department, but so far no response.

 

Is the PTC running on the 12 volt system or pulling power directly from the hybrid system? I would assume the latter, in which case I also wonder if it has a variable output or it is simply an "on/off" application. Again, assuming the latter, I wonder if the heat wouldn't "run you out of the car" as my parents might say, in mild temperatures.

 

The PTC heater controls I'm certain run on 12v, as all accessories do. But the actual power supply for the heater itself is the HV battery. I would expect it's a variable draw, as it is with all PTC heaters I've seen in EVs. My Bolt would draw a bit over 7kW at full power, but drop down to around 2-3kW once the cabin was warmed.

 

I can't speak to how the PTC heater in the Niro works but I wouldn't be surprised if it had the same logic as the one in my 2010 VW Golf TDI. The electric heater in the Golf was never used to provide heat by itself, rather it just acted to (slightly) improve the delivery of cabin heat on cold days to counteract the slow warmup time of the diesel. The PTC couldn't really warm the cabin on its own, but it did provide a bit of heated air while the engine came up to temp.

My assumption would be that there is no user accessible way to control the PTC heater. It probably runs automatically when the engine is cold and there is demand for cabin heat and once the engine coolant is warm enough to provide heat ii shuts off.

 

I can't speak to how the PTC heater in the Niro works but I wouldn't be surprised if it had the same logic as the one in my 2010 VW Golf TDI.

Nah, those were not designed to actually heat the cabin, and from what I remember they had less than a 1kW draw (it had to draw from the 12v battery, so there's limits on how much power it could draw for how long). They were only set up to provide a trickle of heat to help with defrosting before the diesel could warm enough to really provide some heat. My Bolt had a form of PTC heater (it heated a water reservoir to circulate within a heater core like with an ICE), and from everything I can find the Niro PTC heater is supposed to be able to warm the cabin same as the Bolt did. I just found an official Kia document that says the PTC heater is 5.5kW, so should be more than sufficient for temps down into the 40s(F).

 

I've sent a message to Kia Corporate about the functionality of the PTC heater. I'll see if they have any better explanation than the manual does (which is none). I'm still wondering if it's a pre-delivery configuration that didn't get changed after transport.

 

In the winter, the Niro PTC heater is entirely sufficient on its own to warm the cabin without the ICE.. As I said, in below-zero temperatures, my Niro happily goes around in EV mode using the PTC heat without ever starting the ICE... I only got the random ICE starts in intermediate temperature conditions when ICE really should not have been needed for anything at all, which is why I attribute the symptoms to a Kia/Hyundai idiosyncrasy...

Now I would characterize the quality of heat from the PTC as "gentle": rather than noticably warm air blowing from the air vents as when the ICE is providing heat, when the PTC is working, the air from the vents is only just a bit more than "not cold" and the cabin just comes up to temperature and is "comfortable".

Though somewhat subtle, the effect of the Niro PTC is much more noticable and effective than the electric heat on my Prius, which really just helped speed the window defrost and needed the ICE for actual cabin heat...

 

In the winter, the Niro PTC heater is entirely sufficient on its own to warm the cabin without the ICE.. As I said, in below-zero temperatures, my Niro happily goes around in EV mode using the PTC heat without ever starting the ICE...

That's exactly the behavior that I am expecting, although the random ICE starting when temps are simply "moderate" is something that shouldn't be happening. 5.5kW should be fine for warming the cabin, so I am still suspect that it's somehow disabled in the settings that only a dealer can access. I'll see what Kia Corporate has to say about it sometime in the next couple of days.

 

I agree with c_4 about the behavior of the PTC and the Cold Weather Package. Very effective, and the ICE never comes on for heat in EV mode. When it is relatively warm outside, the interior warms to the set temp rather fast, but you never get a blast of hot air.

As for the ICE starting at odd times for no apparent reason, that has occurred with our PHEV a few times. There appears to be no correlation between air temperature and the events. The only pattern in our case was the car was stopped. When it occurred, the ICE started and ran at high idle (1,300 rpm), but did not drive the car. The ICE did not restart if the car was shut off and immediately turned back on. It behaves exactly the same as the condition when driving and the drive battery is nearly depleted. When driving in EV or EV+ and the battery is nearly depleted, the engine starts, warms a bit at high idle without driving the car, and then switches to HEV.

A suspicion about why the ICE starts at odd times is the sensor systems are not reading the drive battery charge correctly, or sense a sudden drop in drive battery charge, and the computers are starting the ICE in the event it may be needed. In one instance, the ICE started, ran a short time, and shut off on its own. It has now been months since the last instance.

 

As for the ICE starting at odd times for no apparent reason, that has occurred with our PHEV a few times. There appears to be no correlation between air temperature and the events. The only pattern in our case was the car was stopped. When it occurred, the ICE started and ran at high idle (1,300 rpm), but did not drive the car.

For myself, I absolutely see a temp correlation. And it is happened when driving, so the stopped condition isn't the same either. On the days the outside temps were always at or above the HVAC setting (usually 72F) the ICE has never come on. This morning my drive in was at 60F, and I tried setting the HVAC to 70 (down 2 degs). The ICE never came on today like it did yesterday under almost identical outside conditions. Pretty strong correlation in my opinion...

 

Here is an explanation of how the PTC Heater works in another type KIA Vehicle -see if this is useful and if you think the logic for the PTC applies to the NIRO operation you describe.

 

Here is the operation on yet another Kia Model - this may indicate these conditions are universal across all KIA Models for the PTC operation.

 

That is probably the answer. Based on these charts, there's a outside temp above which the PTC is disabled, and it looks like it has to be below around 56F before it will work. That seems rather arbitrary, and if it's accurate (no reason it wouldn't be) that information should be included in the owners manual. The Cee'd is even lower, being 41F. That Sportage chart is for a diesel powered car, which might explain the higher temps it will come on, since diesel engines don't warm as quickly. Man, I hope mine will come on higher than 41!

I don't understand the logic of disabling the heater above a certain outside temp value. That's where the supplemental heat would be of most value, when it's only in the "cool" area, rather than really "cold".

 

Interesting. I’m exactly 20 months into owning mine and I’ve never experienced the ICE kicking on to deliver heat. Though I don’t recall what the outside temp was when I last used the heater. Have you tested preconditioning to see if the PTC or ICE kicks on?

 

Have you tested preconditioning to see if the PTC or ICE kicks on?

Haven't had the need for that yet, as my garage is well over 70 even on the cooler days. The only preconditioning I've done was to cool the car in my work parking lot before I head to the car to leave. And I really wouldn't want the ICE to come on while it's in the garage, even through there's no one sleeping in the house when I leave for work. Just don't want any CO to get circulated through the HVAC system, which of course is also in the garage.

 

I’m sorry. I must have misinterpreted your post. I thought that maybe the PTC is not turning on at all right now and consider trying preconditioning as just a test, more of a curiosity really. I’m not recommending you leave the car running and I’d certainly have the garage door open. Once I confirmed the ICE kicked on I’d just turn the car off.

 

If those charts posted are applicable to the Niro, there appears to be an outside temp limit that the PTC won't activate until it's colder. Doesn't make any sense, but that appears to be a controlling factor.

 

You all have me curious now so I’ll push the heat up to high the next time I’m out too see if the ICE comes on. We’re having a mild spell in the Philly area right now and the highs are only in the 80’s.

 

If you folks are correct, I probably won't see this problem, since I don't turn the heat on at all until it's in the 30's (F).

Is the PTC heater only on the cold-weather package? (I do have that, only because it came bundled with the car).

 

Is the PTC heater only on the cold-weather package? (I do have that, only because it came bundled with the car).

Yes, it's only in PHEVs with the Cold Weather package. The EV comes standard with a PTC heater and an option for a heat pump.