miscrms
Well-known member
It seems like the PTC Heater efficiency is pretty high on people's list of gripes about the 2011/12 Leafs. I had been planning on leaving it out of my conversion all together, given how mild the climate typically is here in Phoenix, but our current lows in the 30s are reminding me that it would be handy to have "some" heat on occasion. I'd really rather not add the weight / space / power draw of the PTC heater loop if I can help it though.
That's gotten me to wondering if it would be feasible to route the HV cooling system loop through the heater core. Has anyone ever looked into the possibility? Seems like this might be of interest to any 2011/12 owner in milder climates.
From what I can tell from the service manuals, the HV cooling system control targets keeping the coolant temp around 58-60C. Not sure what typical coolant temperatures look like in cooler weather though. That's a bit cooler than the 70C target for the heating fluid, but still maybe warm enough to provide a bit of heating when needed in mild climates?
I haven't been able to find a clear description of the various air pathways through the HVAC unit, so I'm unclear as to whether the blower airflow is always across the heater core or not. The function of the "Air Mix Door" between hot air and cool air leads me to believe there is a bypass path around the heater core, and air is only blown across the heater core when heating is requested.
There could also be some challenges in regard to the hvac control system. So far I can't find any discussion of failsafe conditions beyond those that shut down the AC compressor. Hopefully the system will still allow for heating controls to be applied to the HVAC unit in the presence of DTCs related to disconnecting the PTC control (as long as the PFC HV interlock is still intact or bypassed).
Any thoughts?
Rob
That's gotten me to wondering if it would be feasible to route the HV cooling system loop through the heater core. Has anyone ever looked into the possibility? Seems like this might be of interest to any 2011/12 owner in milder climates.
From what I can tell from the service manuals, the HV cooling system control targets keeping the coolant temp around 58-60C. Not sure what typical coolant temperatures look like in cooler weather though. That's a bit cooler than the 70C target for the heating fluid, but still maybe warm enough to provide a bit of heating when needed in mild climates?
I haven't been able to find a clear description of the various air pathways through the HVAC unit, so I'm unclear as to whether the blower airflow is always across the heater core or not. The function of the "Air Mix Door" between hot air and cool air leads me to believe there is a bypass path around the heater core, and air is only blown across the heater core when heating is requested.
There could also be some challenges in regard to the hvac control system. So far I can't find any discussion of failsafe conditions beyond those that shut down the AC compressor. Hopefully the system will still allow for heating controls to be applied to the HVAC unit in the presence of DTCs related to disconnecting the PTC control (as long as the PFC HV interlock is still intact or bypassed).
Any thoughts?
Rob