Since there are so many different threads with so many different experiences regarding the FEH/MMH in cold weather....I thought maybe we could consolidate the info in one place where people (especially new owners) could find them. I think it will also be helpful for the rest of us to see if we are all experiencing the same things in the winter, particularly with regard to regenerative braking, ABS, Defrost, EV mode, etc.

Personally, my MPG has dropped from about 30 to about 23 this winter. It was hovering around 27 through Dec & Jan, but this latest cold streak has had temps in the teens all week. I think my NAV MPG is about 23.1 right now.

Other things I've noticed. Increased battery charging times, MUCH longer warm up before EV mode. Shorter duration of EV mode - especially while running the cabin heat. Very high RPM's at low speeds (about 2400RPMs at 20mph!) until the engine warms up.

-Tim

2006 Mercury Mariner Hybrid AWD
Black with Pebble interior
Premium Package with Nav & Moonroof



Current ODO: 26,152
Typical Drive: 20 min crosstown in heavy traffic (3.5mi there and back twice a day)


532 Gallons of gas saved
That's 10,642 lbs less CO2 emitted

If you short the OAT sensor the ECU will not know it's near or below freezing and therefore potentially unsafe to use high levels of regenerative braking. But I wouldn't do it in known low traction roadbed conditions.

I don't think I would do that under ANY conditions. Sounds like a great way to void a warranty, not to mention potentially damage the vehicle.

Tim - I have seen an almost identical experience with mpg this winter....so I'm going to assume my FEH is performing as designed. [My wife's V6 vehicle has dropped from 18 to 13 avg mpg in the last month] I think it helps to remind everyone that the non-hybrid alternatives also suffer in the cold months - so the relative FE advantages of the FEH still exist.

I'm not convinced this is done of the FEH. Once the engine warms up and the battery I've seen completely normal regen of completely normal magnitude at 13F and below. I even have recordings of my NAV display and charge/assist meter while doing it. Also... I noticed no issues with control even on somewhat slippery conditions.

In "D" regen on the FEH seems less powerful than full bore engine braking on the automatic transmissions I've driven.... I've never had alot of trouble with engine braking on any of the automatics I've had, you just have to understand it and how it works. Perhaps Ford didn't worry about it because the problem shouldn't be any worse for regen than for an automatic doing engine braking and Toyota decided differently.

my mpg has taken a nosedive the past two weeks. this morning was the first day in about a week that the temp has been ABOVE ZERO when i left for work. there was one morning last week that was -5F and with windchills it was more like -20F. this is the second full winter i've owned my FEH so i knew what to expect, but the cold is still bitter. i think even the most conservative driving habits can't beat mother nature with these temps. it makes me cringe to think that my old ICE escape only managed about 14mpg in the equivalent weather.

when i'm stopped at a light, the engine rarely stays off for more than 20 seconds or so. EV mode only lasts for short distances, even when the battery appears to have a full charge. my nav system has only been reading about 25.5mpg, and that was a sharp drop from 28mpg at the beginning of january. i try to minimize using the defroster, but too much moisture and it just freezes on the inside of the glass.

anyway, we're supposed to have a high of 24F in detroit on friday. i think i'm going to wear shorts and open the moonroof

courtney | cork@bluemarble.net

The best way to beat the cold is to ACTUALLY make the FEH warmer with engine block heaters, air blocks to the radiator grille, and/or interior warmers ( park in a garage). Perhaps you could use an electric blanket on the battery pack? But in a sense, in every electrically powered solution, you are just shifting pollution from the gasoline burned in your car, to the fuel burned at the power plant.... which is why I like the recycled cardboard radiator block best. Takes zero watts to operate, and speeds engine warm-up time, speeds first EV time, and EXTENDS EV time... not by adding watts or anything, but by simply keeping things above the lower temperature limit for EV. The water temp, must be above 140'F to enter EV mode, and above 125'F to stay in EV mode if you are already there, else the ICE burn gas just for heat.

Ford has directly stated ( well, they did in October 2005 ) that they are officially opposed to Plug-In hybrids... because as of 2005, the pollution per watt from a power plant was greater than the pollution per watt produced from burning gas in the FEH. ( hydro, wind, solar, nuclear power excluded... but not wide spread in the U.S. )

So just driving normally, even with reduced MPG is still pretty good, and very, very clean.

The best way to get 3 MPG extra from your FEH in winter is to put more air in the tires. Keep them at 44 psi all seasons, except lower psi, down to 35 psi is recommended if you have frequent snow / ice. I take the effort to keep the tires at 44psi even in winter, and take them down to 35psi only on those particular snowy days. ( it's very easy to let air out, if needed on the go, so why not try them at 44psi for those "normal" driving days? )

-John

Forgive a clueless question, but: do you cover the entire radiator front or just partially (I've seen trucks that do one or the other). I don't want to do any damage to my 06 MMH, but this frigid New England weather has got me down to 23 mpg, like many of you, and I'm smiling less than I was as a new purchaser in the fall!

The misses and I also had a reduction in miles per gallon
with the advent of cooler weather. At first we thought it
was due to us and then when both of us lost about 2-3
miles per gallon each at roughly the same time period,
we realized that even our mild coolness here has affected
our overall gas mileage. The misses 2006 MMH 4wd
has gotten no less than 27.8 mpg for her and mine no
less than 29.6 so far. She does more city driving and I
do more highway driving.

Jim

I have mine 100% blocked. At 25'F outside air, I never exceeded 207'F ( the hottest I've ever seen the car ) climbing a 7% grade at 65 MPH with sustained 4000+ RPM for like 20 miles / minutes.

No radiator block would have been about 188'F to 190'F on that same hill.

Above about 190'F the electric radiator fans come on ( or come on loud enough to hear at a stop, maybe they are on low speed all the time? ).

But in city, stop and go, when EV is possible and desired, my radiator water is in the 145'F to 160'F range when outside air is 25'F.

Without a radiator block in stop & go, my radiator water falls below 140'F and EV becomes nearly impossible.

How fast your radiator water cools also depends on how much heat you use inside the cabin. Even a low setting will cool your radiator water about 5'F or more per minute when in EV mode.

-John

P.S. With morning commutes about 10'F and evening commutes about 25'F, I'm getting about 33 MPG during 55 MPH highway sections, and about 36 MPG in city sections.