Found the ambient high temperature limits of the hybrid's electric motor/battery

[NewBernWolf]

The transmission in the Mav is very similar to those of Escape's, Fusions, etc. The main difference is the Mav has a water cooled battery. Water cooled batteries are not "untested", every Tesla made has had them. Water allows a much higher heat transfer than air cooling. Just as water cooled engines are considered better than air cooled engines. The previous generation Escape or Fusion would have a similar or worse issues with these extremely high temperatures.

But did they have issues? Does no one drive previous generation hybrids in Phoenix?

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[DesertSweat]

Hybrids don't work in Phoenix? I'm sorry, I just keep wondering why they're sold there. Wouldn't your heat - that's somehow worse than New Orleans, Miami, and other hot southern places - prohibit the sale of hybrids and electric vehicles?

I guess you’re a little slow

Phoenix is way hotter then those places. Right now the hottest time of the year.

Batteries have an operational temperature range. Ambient temp (rate at which the coolant can reject heat) plus recharging and discharging rates will affect the temperature.

There will be safety limits. It turns out the hottest days of Phoenix will see that

if you want to play dumb and think that Ford doesn’t have operational limits and safety control structures within logic in the ECU, I can’t help you.

its not like the truck didn’t work. It just doesn’t work as a hybrid when excessive temps are encountered. The HVB is only used for AC and nothing else to try to keep temps down. Even when AC is off, the HVB when too hot will not discharge and recharge at high amperage levels because that will exacerbate the issue.

you don’t have to be an engineer to understand high temps = bad for battery. Control logic will be in place to prevent damage.

 

[DryHeat]

Hybrids don't work in Phoenix? I'm sorry, I just keep wondering why they're sold there. Wouldn't your heat - that's somehow worse than New Orleans, Miami, and other hot southern places - prohibit the sale of hybrids and electric vehicles?

I see you're from North Carolina. Maybe you're not familiar with summer in the desert.

Over the next week, Phoenix will have 5 days of 111 degrees or above. (Last week was hotter -- up to 116 degrees -- but it's cooling off nicely now as our Monsoon season comes in.)

Over the same period, the highest temperature in New Orleans will be 91 degrees, and in Miami it will be 90 degrees.

That's a difference of 20 degrees or more. So, yeah, for a battery Phoenix is "somehow worse" than New Orleans or Miami.

 

[Shay]

I'm surprised that there is no warning on the instrument cluster about the battery charge/discharge being limited due to excessive heat/cold.

There is no reason to warn over it. It's not broken.

 

[MostlySafeBear]

There is no reason to warn over it. It's not broken.

If it's stopped either charging or discharging the battery due to excessive heat or cold, then yes, it is broken in the sense that the truck is not fully operating.

Recall that the hybrid ICE is specifically compromised (atkinson cycle) for the sake of efficiency to run worse at idle/lower RPMs, where the electric motor is supposed to assist.

 

[Shay]

If it's stopped either charging or discharging the battery due to excessive heat or cold, then yes, it is broken in the sense that the truck is not fully operating.

Recall that the hybrid ICE is specifically compromised (atkinson cycle) for the sake of efficiency to run worse at idle/lower RPMs, where the electric motor is supposed to assist.

But the conditions discussed in this thread are not faults of the system, it's a programmed operating mode. When it's extremely hot the battery has less juice for all the stated reasons in previous posts, the engine runs more often or near 100% of the time to keep the battery adequately charged and to power the vehicle. That's it. That's all.

It's not a problem or something that needs to be warned of or corrected. It's an operating mode for extreme conditions. It's designed to behave this way. The only "issue" is that you get less fuel economy.

 

[MostlySafeBear]

But the conditions discussed in this thread are not faults of the system, it's a programmed operating mode. When it's extremely hot the battery has less juice for all the stated reasons in previous posts, the engine runs more often or near 100% of the time to keep the battery adequately charged and to power the vehicle. That's it. That's all.

It's not a problem or something that needs to be warned of or corrected. It's an operating mode for extreme conditions. It's designed to behave this way. The only "issue" is that you get less fuel economy.

Given that we agree that it is a programmed operating mode, then as a driver, I would still want to be informed, via an instrument cluster message, that the truck was limited due to temperature, and what I should do. Drive home? Serious enough to pull over and call a tow? Etc.

The Maverick owner's manual PDF talks about "Fail-Safe Cooling" on page 306 of the PDF version. It specifically says that it is "for use during emergencies only. Operate your vehicle in fail-safe mode only as long as necessary to bring your vehicle to rest in a safe location and seek immediate repairs."

That's much more concerning than the simple issue of reduced fuel economy.

What concerns me is that it the truck did not warn the driver of this condition.

 

[Eagle11]

It was about 114-115F yesterday, display was reading 118 while caught in a little bit of traffic in Phoenix. Nothing unusual. The car started driving unusual. I could tell that regenerative braking was hardly there. The engine would not turn off even coasting or stopped. AC or AC off. Drove the last couple miles home to see if I could get the car in electric mode, but nothing. Everything is working fine this morning.

My guess is once the high voltage battery gets too warm it limits charging and discharging to keep it cooler.

Most of you guys won't have to worry about this. And luckily there are few days over 115 in Phoenix, so hopefully it doesn't become too much of a problem.

On 7-11 when we had the hottest day here in PHX, my Maverick made some unusual noises and a decrease in power; it's at Camelback ford; I have a video of the noises it was making.

 

[Shay]

Given that we agree that it is a programmed operating mode, then as a driver, I would still want to be informed, via an instrument cluster message, that the truck was limited due to temperature, and what I should do. Drive home? Serious enough to pull over and call a tow? Etc.

The Maverick owner's manual PDF talks about "Fail-Safe Cooling" on page 306 of the PDF version. It specifically says that it is "for use during emergencies only. Operate your vehicle in fail-safe mode only as long as necessary to bring your vehicle to rest in a safe location and seek immediate repairs."

That's much more concerning than the simple issue of reduced fuel economy.

What concerns me is that it the truck did not warn the driver of this condition.

Fail safe mode is not what those of us discussing this matter in this thread are experiencing. Fail safe mode is another thing entirely, where a fault of some kind does exist and the system powers down such that you should park the vehicle or limit its use. If you are in fail safe mode it's because there is a mechanical problem that is causing the system to be unable to operate within its normal programmed modes. This could be low coolant, low oil, or some other kind of mechanical fault. In that case you would have a Check Engine or similar light on the dash.

What we are talking about here is simply a matter of the engine running more often during extreme temperatures than when its cooler. I experience this every day for the last month as it has been 105-115 degrees every day during my driving. The gas engine runs a lot more, not all the time, but a lot more. The performance and capability of the truck is not limited in any measurable way. It can drive and accelerate, city, highway - just with less electric and more with gas engine as a percentage of the time/miles.

It's not a fail safe condition that requires me (or anyone) to change my behavior. It's a programmed mode the truck has to operate in this temperature range. The truck is not "limited due to temperature", rather it is operating differently as a result of it. This is how hybrid vehicles work.

And lastly, you do know what is and is not happening as there is an indicator on the dash that tells you what mode you are running in be it "Electric" or "Hybrid" mode. The latter being the gas engine is running during operation along with the electric motor/generator.

 

[MostlySafeBear]

My point is that you can't tell the difference between heat limiting the hybrid battery and fail safe cooling mode because you're not informed as a driver. You just have to guess.

To me, that is a bad UI choice.

 

[Shay]

My point is that you can't tell the difference between heat limiting the hybrid battery and fail safe cooling mode because you're not informed as a driver. You just have to guess.

To me, that is a bad UI choice.

No. If your vehicle is in a fail-safe mode you would have a check engine or similar indicator on as you would genuinely have a problem. That is part of the OBD SAE convention all cars adhere to.

 

[Hoagus]

Up here we would need to add the temps of 2 days together to hit 118F.

Now, at the other end of the spectrum, I'm wondering how well that battery will enjoy -35F with a windchill of -55F. That should be interesting how much charge the battery will hold.

Surely there’s some history of this in the Escape. Do they have a similar battery placement?

 

[MostlySafeBear]

XL Area 51 Poverty Edition

I don't believe I'm familiar with that exact trim. Do you have to get out and push?

 

[Hoagus]

The operating temperature limits should be in the manual.

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