Newer Heat Pump Systems

I have just had my Leaf a couple of weeks.

I'm curious. I have a 2015 SV. I have read on other threads that the Heat Pump motor is variable speed. I assume it draws power from the main battery pack. Is it a DC motor?? Where is its power routed through and how is it controlled? I wouldn't think that it would be powered by the main inverter.

Also, is there a heating element used somewhere in the system? It would seem as though there would have to be a heating element for really cold weather or defrosting/defogging.

I know the heat pump system also incorporates a resistance heater like the earlier Leaf. This "PTC" heater supplements the heat pump down to about +5F (doing most of the heating below about 23F) and then replaces it completely. That's why it is often called the "hybrid heating system."

LeftieBiker said:

I know the heat pump system also incorporates a resistance heater like the earlier Leaf. This "PTC" heater supplements the heat pump down to about +5F (doing most of the heating below about 23F) and then replaces it completely. That's why it is often called the "hybrid heating system."

Click to expand...

Does the resistance heater use circulating fluid, or just air passing over a heating element??

It is your AC running backward with a valve added, It runs off the pack HV. The inverter powers the car motor only the DC/DC powers the cars 12V system.

Nhinman said:

LeftieBiker said:

I know the heat pump system also incorporates a resistance heater like the earlier Leaf. This "PTC" heater supplements the heat pump down to about +5F (doing most of the heating below about 23F) and then replaces it completely. That's why it is often called the "hybrid heating system."

Click to expand...

Does the resistance heater use circulating fluid, or just air passing over a heating element??

Click to expand...

It uses fluid.

The motor that drives the heat pump compressor is AC and has its own small inverter.

Ah, is that why Leaf Spy reports the AC as drawing power when I have the heater on?

LeafSpy has a reading for heat and one for AC. I wonder if the reading for heat is the resistance type heating and the AC is the heat pump? The other day I notice energy consumption on both and when I dropped the temperature by on degree, the "heat" dropped to zero but the AC stayed on (-5C day).

LeftieBiker said:

Nhinman said:

LeftieBiker said:

I know the heat pump system also incorporates a resistance heater like the earlier Leaf. This "PTC" heater supplements the heat pump down to about +5F (doing most of the heating below about 23F) and then replaces it completely. That's why it is often called the "hybrid heating system."

Click to expand...

Does the resistance heater use circulating fluid, or just air passing over a heating element??

Click to expand...

It uses fluid.

Click to expand...

I spent some time looking under the hood. I could not see any water lines running through the firewall. I was somewhat confused by 2 sets of lines running from the heat pump into the cabin. I looked at the service manual, and noticed that there are 2 heat pump coils in the cabin. The service manual shows a PTC heater in the cabin, but no water lines. I am guessing that the PTC heater is run off the higher voltage of the battery pack, but I am not sure. It also appears that it must be just air flowing over the heating elements. The service manual does show heat shields around the PTC heater. I will have to look for the high voltage connection. The service manual was not clear on this.

LeftieBiker said:

Nhinman said:

LeftieBiker said:

I know the heat pump system also incorporates a resistance heater like the earlier Leaf. This "PTC" heater supplements the heat pump down to about +5F (doing most of the heating below about 23F) and then replaces it completely. That's why it is often called the "hybrid heating system."

Click to expand...

Does the resistance heater use circulating fluid, or just air passing over a heating element??

Click to expand...

It uses fluid.

Click to expand...

Only old Leafs(~pre 2013)and Leafs without heatpump uses fluid.