There are a lot of posts regarding "cold weather" and the Ford Escape Hybrid on here, but most threads are Upper Midwest specific where -15 is the norm and not the -40 we regularly experience here in Fairbanks, Alaska... 90 miles south of the Arctic Circle. (Or the -60 we occasionally endure.)

I brought my 2008 Mercury Mariner Hybrid AWD here in August (from California) and it did fine during the warm summer and cool fall temperatures. Starting about three weeks ago, we entered this cold spell of -20 to -40 temps which aren't going away. I've had the head bolt heater installed, a remote start system installed, and got a custom vinyl wind cover for my grille. Still, I can not get the car warmed up to operating temps at -40F ambient air temp.

According to what I've read, it requires about 15 minutes to raise battery temps by 10 degrees F. The electric motor operating temp is at 180 F, and the battery works between 60 and 150 F. So if your car is out all night and hits -30 F, the battery will require over two hours to warm to operating temps.

((60F-(-30F)) / 10F)*15= 135 minutes = 2.25 hours

As such, I can not get my car into HEV operating mode. I'm getting 8mpg, including idling time to warm up and the fact that the electric system is actually dragging down fuel economy (by revving at high idle ALL THE TIME) as opposed to bringing my gas mileage up.

Post-2005, there is supposedly no way to additionally heat the battery by overriding the internal battery heater in the HV battery case. An external battery blanket will supposedly not be effective due to the insulation on the HV batteries.

I have done a ton of research, and wrote this thread to share it... but if anyone can provide any other useful tips (other than moving to a place with a garage), that would be very helpful.

 

Have you checked in with Ford, Ford corporate, not your local dealer, to ask them if they have any ideas or recommendations?

 

I've noticed that if I'm parked somewhere long enough for the FEH to cool off, and the driving after starting involves a long downhill and it's "cold", say around the freezing point, the FEH will not go into EV mode even if the speed falls well below the limit for EV operation. Such as going around switchbacks which are flatter but slower than the rest of the descent.

But in summer, it will go into EV mode on those same corners. I theorize this is because one thing the system has to do is keep the catalytic converter hot, and it won't stay hot in cold weather without the engine running AND burning gas. The engine may run on these long descents (actually engine braking as much as possible in the case in mind) but it's burning no fuel. So it can't heat up anything. Heat demands for the hvac system may also dictate that the ICE won't shut off if it's very cold.

Compared to a non-hybrid, a hybrid would get worse mileage in a certain pattern of driving. Many short trips with enough time between them to allow the ICE and traction battery to cool off would mean you're using gas to reheat both of them all the time, rather than just reheating the ICE as in a non-hybrid.

 

I hate to tell you this but at 40 below, NOTHING is going to be fuel efficient. If you talk to some of the other locals, they will tell you the same. A heated garage will help somewhat but parking at work for a few hours at those temps will have the car so cold soaked that it will not warm up enough to go into EV mode on the trip home.

 

Yes, you beat me to adding that non-hybrids are going to get pretty lousy mileage in extreme cold also.

And it bears mentioning that with the very large NiMH battery and electric motor as a super starting system, the FEH should start reliably in the worst cold.

 

How does a head bolt heater differ from a block heater? Perhaps you need both? Apart from keeping it garaged, it might be better to park it (12V disconnected) and then run the main battery up to operating temp at least once every 3 -4 weels using FORSCAN as a control panel. Our mileage has dropped 15% in southern Ontario temps and we keep Hippo in the garage, avg temp = +5 degrees since the garage is well insulated but not heated. Block heater is used almost every day when temps below 0 C outside. Unfortunately, it seems these particular MEH/FEH's are fair weather friends in an Alaskan/Yukon environment

 

>>>> I saw report on the internet of the engine thermostat sticking open. If you haven't had that checked, it might be a good followup on this issue. Thermostats are typically simple and inexpensive to replace.

 

DualWield, any update on cold-weather running of your 2008 MMH?