Winter observations from an LFP Mach E owner.

[redgrandam]

Background: car is 2023.5 LFP model RWD. Purchased late last winter.



Parked for 18 hours, overnight, unplugged outside. -21C overnight. Was -19C when I went out to car around 10am.



Bat temp went down to -14 / -11C range. When plugging car in (not charging) battery heater came on. When charging triggered it stayed on and was adding a bit of power beyond coolant heater.



Upon starting to drive, coolant was warm from being plugged in for 5 mins. Battery heating mode went (from heat) to OFF and remained this way untill battery inlet temp (which got up to about 2C after a couple mins of charging) reached the battery temp (by now about -11 / -8C after driving for about 10 mins or so. Then it went to EQ mode which seems to warm the battery with inverter excess heat. Inverter temp dropped from about 50C to -3C. Inlet then sits a few degrees above highest battery temp for the rest of the drive. Battery was -5 / -3C at end of drive.



At start of drive coolant heater was pegged at over 7kw. At no time did it seem to use this heat for the battery whole driving.



Was allowing 10kw regen at start of drive. And 20kw or so near end of 25 min drive. No power reductions noted, acceleration used was up to about 100kw to test it (did not floor it though).



First leg was 31 km drive (car not preheated) went from 50% to 31%.



Got back home with 14% SOC. No warnings or power reductions. 40kw regen on the way back. Battery temp back home was above 0C, and full power to motor was allowed.



12V stayed at 70-72% the whole time.

Sponsored

 

[Mach-Lee]

So I'm a little unclear with your description, you said the battery temp warmed up from -14ºC to 0ºC while you were driving? Or did you leave it plugged in to warm up before driving?

If the coolant heater was pegged at 7 kW the whole drive, then it's likely it was using it to warm the pack. Remember the heater core and battery can be heated at the same time.

It's also interesting you have a cold regen limit enforced, Ford does not do any kind of regen limit on the NCM packs even when they're very cold (-10ºC) until they get to low SoC.

 

[redgrandam]

So I'm a little unclear with your description, you said the battery temp warmed up from -14ºC to 0ºC while you were driving? Or did you leave it plugged in to warm up before driving?

If the coolant heater was pegged at 7 kW the whole drive, then it's likely it was using it to warm the pack. Remember the heater core and battery can be heated at the same time.

It's also interesting you have a cold regen limit enforced, Ford does not do any kind of regen limit on the NCM packs even when they're very cold (-10ºC) until they get to low SoC.

I plugged the car in just for a minute or two to see what it would do. I wanted to confirm it would use the coolant heater to warm the battery when plugged in and cold, and to verify that it wasn’t doing so when I plugged. I didn’t plug it in long enough to change the battery temp, just to see the coolant heater get up to temp. So yeah, the temp of the battery increased while driving. About an hour total driving to go from -14C to 0C. During the drive it was definitely not using the coolant heater to warm the pack. I know this for a few reasons. First, when it is really heating the pack with the coolant heater (like plugged into the wall, or preconditioning for DCFC), it switches modes to ‘heat’. The HV inlet temp also increases to roughly 30C or something in that range, I can’t remember exactly. It is clear it is heating the battery at that point.
When I start driving with a cold battery any day, after about 2-3 mins of driving, I’ll see the inverter temp is roughly 20-40C (depending on the day and weather). Then it will suddenly drop to fairly close to the battery temp. At this time it also switches the battery heat mode from ‘OFF’ to ‘EQ’. Prior to this the HV battery inlet temp was the same as the battery, but when it goes to EQ mode the inlet temp stays just a bit above the battery temp the entire time. Eventually the inverter temp starts to climb back up but it never get super warm during this EQ mode. It is clear that when that switch happens is has started pulling all the heat it can from the inverter
If the battery heat mode goes to ‘heat’ the inverter temp goes back to approx 50C I believe because it is no longer stealing heat from it.
Normal temps when I’m at work might be -10C outside. My hour long drive home will end up most days with a battery temp in the 5-7C range roughly.

The coolant heater was only maxed out for a little bit. It settled down to roughly 4-5kw average for the most part. Once I turned down the fans it was more around 3-5kw. When it’s heating the battery with it, it stays 100% pegged over 7kw.

I have enabled the power meter on the display of the car, and it as expected reflects my regen observations. The cold battery regens about the same as it deals with a battery at 100%. It uses a little regen, but one pedal driving still works seamlessly because it blends in friction brakes to make up the difference. When I leave my house in the summer with a battery at 100% it has minimal regen untill around 95% SOC. By around 90%, I can get pretty well full regen if the battery is warm. It still allows a lot more regen than my Chevy Bolt with NCM battery gets on a cold battery. I have never noticed a reduction in regen with low SOC but I rarely get below 10%.

 

[Shayne]

I guess slick when the battery is below 0C and blended braking. No wonder the rotor rust dust is too much right now as we can not wash them until the spring. My wheels are all a nice rust color right now while I never touch that pedal; that would explain why.

Best to keep them plugged to a L2 and set departure schedules when you can. Want the batteries warm turn the HVAC heat off while driving. Heated seat and wheel on with the window cracked open. I am good for 20 minutes down to about -20C To about -10C I don't need it on

Can't attach images/ODB graph right now? Battery temp flat lines when HVAC heat is on. HVAC heat off (can leave fan on) and recirc pump kicks in and battery starts to heat up. Runs for 20 minutes bat temp goes from 0C to 15C (all averages) then auto shuts down. Turn HVAC back on. Know the car if you need the range. Watch the range go up when the battery is heating and you are still driving. If you can live without cabin blower heat you will go farther. Start plowing through 15 cm of snow and panic sets in.

I find the range is still plenty for my winter travel (heat on) as I do not do much long distances in the winter with more commuting. -20C last time preconditioned and used 33% when in the summer it takes no more than 20 (80 Km +/-). Really does not matter both are plenty and charged up again by the next morning in the winter. Additional cost $3.50 including preconditioning. That is about double what it costs in 20C.

On L2 the car has been working great for the last couple of winters in the cold. If the winter range is good for your needs LG.

Sponsored