Winter Noob Questions

[DrDeke]

As the weather gets colder (mornings in the 20s and 30s), I am noticing that my 2012 Fusion Hybrid tends to run the ICE to the extent that the HV battery gets completely full at times during especially the early part of the commute. This happens less often if I leave the cabin heater off or very low, but if I do that, I often run into windshield fog trouble. Presumably, when the HV battery is full, it stops accepting energy, so being in this condition would impact mileage.

 

I have two questions about this:

 

1. Is this par for the course for city-street driving on these cars in the winter? Or are there habits I might be able to learn to help avoid letting the battery get completely full?

 

2. If this is something that commonly happens, have any of you ever run a (heavy gauge) cable from the 12V battery into the cabin (as one would for a big audio amplifier or ham radio rig) and used it to run, say, a 400-700 Watt resistance heater? 700W @ 12V comes to just under 60A, which the DC-DC converter should be able to accommodate under normal operating conditions. If the energy from the ICE idling is otherwise going to go to waste, it seems like this might be a nice little workaround; use some of the electric energy which would otherwise be wasted, while also reducing the need to run the built-in cabin heater...

[Cobra348]

I can't speak to number 2, but this morning it was 30 and the FFH had a nice heavy frost all over. I remote started which kicked the ICE and climate control into high gear. ICE did run even though the HVB was full ... for about 8 miles. I had max defrost on only to clear the glass, then went auto on the climate and used seat and steering heaters. Based on my experience today I think this is normal operation in the colder temperatures.

[lolder]

This is normal winter behavior. Getting a big cable through the firewall would be an enormous headache. You would need two including the ground. Operate the HVAC in AUTO with a set comfortable temperature. It will usually defog automatically as there is a humidity sensor in the cabin.You can select it to deice. Put on the rear defog also.

[Griswald]

When the ICE runs and the battery is full, you will get the BEST MPG's. It seems kind of counter-intuitive, but since all energy is moving the car and no energy is going to the battery, the ICE is at its most efficient mode.

 

Also, I don't use the heater very much in the cold, I crank the seat heaters up to max and leave the auto temp at 65. With the seat heaters and heavy clothing, even 65 gets too warm.

[hybridbear]

Max defrost will make the ICE run versus just using defrost & a lower fan speed. Defrost will make the ICE run more than using floor or panel vents. Defrost will activate the ICE to make heat (or the electric heater in an Energi) plus the A/C compressor to dehumidify the air. This results in the maximum hit to MPG since you're demanding both heat & additional dehumidifying at the same time. Max defrost demands maximum heat & maximum dehumidifying so it's the worst in both senses.

Edited November 10, 2015 by hybridbear

[Waldo]

When the ICE runs and the battery is full, you will get the BEST MPG's. It seems kind of counter-intuitive, but since all energy is moving the car and no energy is going to the battery, the ICE is at its most efficient mode.

 

 

This is not quite accurate, The ICE might be burning less fuel when it's not charging the battery, but that doesn't mean it's operating at it's most efficient point. The counter-intuitive part is that ICE's generally are more efficient when they produce more power, not less. The whole point of a hybrid is to allow the ICE to run at it's most efficient point and store the excess power produced so that it can be used later. That's why running the ICE once the battery is "full" will never give you as good a trip MPG as turning off the heat and the ICE.