What happens at end of range?

Skip Towne

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This is a bit of a report about what happened when I got CLOSE to the end of range and a questions about what would have happened if I kept going?

I started out a late night trip to the White Mountains of NH - where there are no charging options other than the charger at my destination. The northernmost DCFC is Manchester NH. It is usually a very quiet ride, NO traffic.

Started at 93% charge in my LR AWD MME Premium - the one with ficticous 270 mi range. the GOM said I had 168 mi range - ok for the 140 mi trip. When I started, the air temp was 20 deg.

By the time I got to "no where" in the mountains, the air temp was down to 0 deg and dropping. The GOM was dropping range much faster than I was travelling. At one point the GOM showed I didn't have enough range to make my trip. And I was on the most desolate part of my trip. I began to think I was going to stall out in the White Mountain National Forest and die a long, cold death before sunrise or any passerby came to save me or mock me for testing the BEV limits in sub-zero weather.

When I reached my "low battery" limit set at 30 miles, I took the advice to turn off climate control. My, how quickly the cabin temp drops when you do that. The panoramic glass gets real cold, real quick. I was remembering those scenes in the Apollo 13 movie with freezing astronauts, as I navigated my Mach-e spaceship through the desolate, dark, cold national forest. (queue forbodding music)

The center panel was flashing warnings that no charging options existed in my remaining range. It did tell me to prepare to plug in somewhere - without advice where. It thankfully made no mention of dying from hypthermia. It made no mention of notifying next-of-kin.

Miraculously at some point (about an indicated 15 miles, 8% battery left) the range started to extend - the GOM would drop 1 mile with every 2 or 3 travelled . Does anyone know if that was because the heat pump was warming the battery instead of the cabin? Or just a glide path of range use? Or the GOM starting to tell the truth under duress?

As I reached the end of my trip with still 4% battery and 10 miles range left on GOM, I tried to test my traction (did I mention the snow falling at 0 deg temp?) by trying to accelerate hard. The MME wouldn't accelerate hard - at all. It wasn't traction controll kicking in, it seemed to be a "don't be stupid, you are almost out of power" control mechanism. Anyone know that to be real? I've heard of Tesla's Limp Mode - does MME have a similar "I'll get you there, but slowly" mode?

Does anyone know what happens if you just keep going? How far out does it really stretch the range I.E. would you have 5 miles left for 10 or 12 miles? Does the MME just stop when the GOM gets to 0? Does it ever actually use the battery buffer or just stop because the driver is so stupid to go to indicated 0 mi range? I didn't want to test this in the situation I was in, but now that I survived, I remain curious.

Oh yeah, I'm trying to shedule the CSP 21P22 update, which reportly increases cold weather mileage, among other things. Seems like a good idea, now that I had time to think about it-- in the cold, while considing my mortality.
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SnBGC

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I don't really know. Lowest I got was about 3 miles or so.

Our C-Max Energi knew when it was close to home (like turning into the neighborhood) so it would allow the car to use the Hybrid portion of the battery to make it home without turning on the engine. There was a notification icon on the dash when that occurred.

According to my niece, the Focus Electric would stop at 0%. On that day, she was about 3 blocks from home so she programmed her home in the Nav and set it as a charge destination and the car let her drive the rest of the way.

While the C-Max Energi and Focus Electric are both Ford products.......I am quite sure the software programming strategies are completely different so I would not expect the Mach-E to perform the same way.

Would be interesting thing to test though..... ?
 

Craigeddy111

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AeroEng

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This is a bit of a report about what happened when I got CLOSE to the end of range and a questions about what would have happened if I kept going?

I started out a late night trip to the White Mountains of NH - where there are no charging options other than the charger at my destination. The northernmost DCFC is Manchester NH. It is usually a very quiet ride, NO traffic.

Started at 93% charge in my LR AWD MME Premium - the one with ficticous 270 mi range. the GOM said I had 168 mi range - ok for the 140 mi trip. When I started, the air temp was 20 deg.

By the time I got to "no where" in the mountains, the air temp was down to 0 deg and dropping. The GOM was dropping range much faster than I was travelling. At one point the GOM showed I didn't have enough range to make my trip. And I was on the most desolate part of my trip. I began to think I was going to stall out in the White Mountain National Forest and die a long, cold death before sunrise or any passerby came to save me or mock me for testing the BEV limits in sub-zero weather.

When I reached my "low battery" limit set at 30 miles, I took the advice to turn off climate control. My, how quickly the cabin temp drops when you do that. The panoramic glass gets real cold, real quick. I was remembering those scenes in the Apollo 13 movie with freezing astronauts, as I navigated my Mach-e spaceship through the desolate, dark, cold national forest. (queue forbodding music)

The center panel was flashing warnings that no charging options existed in my remaining range. It did tell me to prepare to plug in somewhere - without advice where. It thankfully made no mention of dying from hypthermia. It made no mention of notifying next-of-kin.

Miraculously at some point (about an indicated 15 miles, 8% battery left) the range started to extend - the GOM would drop 1 mile with every 2 or 3 travelled . Does anyone know if that was because the heat pump was warming the battery instead of the cabin? Or just a glide path of range use? Or the GOM starting to tell the truth under duress?

As I reached the end of my trip with still 4% battery and 10 miles range left on GOM, I tried to test my traction (did I mention the snow falling at 0 deg temp?) by trying to accelerate hard. The MME wouldn't accelerate hard - at all. It wasn't traction controll kicking in, it seemed to be a "don't be stupid, you are almost out of power" control mechanism. Anyone know that to be real? I've heard of Tesla's Limp Mode - does MME have a similar "I'll get you there, but slowly" mode?

Does anyone know what happens if you just keep going? How far out does it really stretch the range I.E. would you have 5 miles left for 10 or 12 miles? Does the MME just stop when the GOM gets to 0? Does it ever actually use the battery buffer or just stop because the driver is so stupid to go to indicated 0 mi range? I didn't want to test this in the situation I was in, but now that I survived, I remain curious.

Oh yeah, I'm trying to shedule the CSP 21P22 update, which reportly increases cold weather mileage, among other things. Seems like a good idea, now that I had time to think about it-- in the cold, while considing my mortality.
You need to read this post: https://www.macheforum.com/site/thr...-mach-e-range-test-what-could-go-wrong.11669/

He answers a lot of your questions with a great cold weather test.
 


vulpes

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State of charge is simply voltage of the battery. Lithium Ion batteries have operating voltage range, if you dip below that range, they'll keep giving you power, but at a cost to battery integrity. Many people have revived completely discharged battery packs (less than 1V on a 52V pack), but that comes at a cost to longevity and capacity.

MachE has a system in place called BMS (battery management system), which will turn the pack off and won't let you use any more of it at a certain voltage. Its below 0% indicated from what we've seen, but how far, is anyone's guess. Before the system completely turns off, it will give you a "turtle" icon, which you might've experienced. That might've been traction control doing its job, though.

Batteries have 2 operating temperatures. One is for discharge, which will go into negative celseus, and one for charging, which has to be at above 0 C. At low state of charge, it won't run the heater to keep battery warm, but the same coolant that is used to keep motors cold is used to heat the battery, so the battery will warm up as you drive.

MachE does not come with a heat pump, which is more efficient (2-3x as efficient as resistive heater, which is almost 100% efficient) as it doesn't create heat, it extract it from the environment.

On your trip you were "fine" and in no danger, although I wish the car would do a better job communicating that.

My suggestion is always the same with maximising range in the winter - turn the heat off or down (keeping the cabin at 60F takes a lot less energy than keeping it at 70F), use seat and steering wheel heaters and go slow.
 

nvabill

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Throw a gas generator in there and give it a try! ?
 

Doug&Julie

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A lot of the EV testing YouTubers will drive a car until it reaches zero. Some go until they literally stop. This is the most recent one that comes to mind...
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