Why Can't The Mach-E GT Do This?

[Mach1E]

We're just guessing whether it's timed, or based on one of the temp sensors.... unless there has been a post from Ford Engineering I missed?

My bet is that it's temp, but I dunno WHICH sensor. Probably not ambient, but likely to be any or all of the internal motor, inverter, battery sensors. Most likely a sensor buried in the battery tray.

I can tell you from my own experience with my eMiata, that pulling 5C or 10C through connections that are designed to handle continuous current of no more than 1C has a pretty quick effect unless the heat transfer is optimized to cool the cells. External air cooling won't help *much*. I'm talking about coolant chilled as cold as you can get it to extract as many BTU as possible.

since we can't easily open up the battery pack to optimize the internal heat transfer plates, the only thing we can even try to modify is the inlet temp of the coolant prior/during heavy loads. If I were a drag racer interested in modifying to see if I could squeeze out another second or two at full current..... I'd test the theory since I doubt we're going to see an official response from Ford Engineering on this.

I wouldn’t call it a wild guess, more like an educated one based on the data.

Is it time or temp? The answer is likely both.

They program all these things using tables (looks like a giant excel spreadsheet). Some are closed loop and some use open loop feedback.

Short answer? At full throttle things happen too quickly to rely on open loop feedback. The 5 seconds is likely a hard stop. ICE vehicles do the same thing at full throttle.

However, feedback like battery temp, external temp, vehicle speed, etc can affect things BEFORE you go full throttle.

That’s why the “grey bars of disappointment” show up in the power meter sometimes before you floor it, or faster than 5 seconds after you floor it.

What has never happened (so far) is anyone getting more than 5 seconds. Doesn’t matter if your battery is perfectly warmed up and it’s cool outside. 5 seconds is the current hard stop.

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[benk016]

I'd love to see which temp sensor spikes under load if you can capture that during a full throttle test.....

one way to get a clue as to whether it is temp or just a 5 second timer would be to do several runs in a row without giving things time to cool between runs. i.e. do you continue to get 5 secs at 100% current, or do it reduce as core temps increase and don't have time to cool.

Here you go.

Outside temp is 42 Degrees. Car was parked in the garage plugged in. Did a remote start for 10 minutes before these runs. Power meter was showing 1 gray bar of limitation at the start, so Not 100% full power but close.

I did multiple runs, charted the SoC, Speed, Power flow, and every temp sensor I could find that would be related.

2 runs I didn't let the gray bars clear from the power meter. You can see those by being limited at around 200kWh.

The main thing I'm seeing is the primary inverter does shoot up in temp quite a bit, but drops back down almost as quick.

Also attaching the spreadsheet file of the data if anyone wants to investigate a bit closer.

I will do this again later, and hopefully I can get the car to not have any limitation on the power meter for the next runs. And I'll try and be a little more consistent on what speed I get to and How quick I slow down. And If someone has something they'd like me to try or add to the testing, just let me know.

 

[Jppumper]

Why is the GT limited to only 5 seconds peak power, it's obvious that not all EV's have this limitation, what gives?

Could it be in the vehicle software? It may be sensing a runaway car at full throttle and shuts it down. Maybe they should install a "RACE MODE" button, lol

 

[tesla2mme]

Could it be in the vehicle software? It may be sensing a runaway car at full throttle and shuts it down. Maybe they should install a "RACE MODE" button, lol

“Red key” would be good… it’s definitely not a software thing defending the car against “run away car” - ostensibly it’s to protect the battery and/or motor from heat issues….. but it’s lame as hell on an expensive HiPo car

 

[Jppumper]

“Red key” would be good… it’s definitely not a software thing defending the car against “run away car” - ostensibly it’s to protect the battery and/or motor from heat issues….. but it’s lame as hell on an expensive HiPo car

I realize that the car has a battery cooling system. Makes me wonder how that battery will hold up to hot charging during road trips. (DC Fast Charging) According to the user's manual, they recommend letting the battery to cool before charging. Good thing that the battery has an 8-year warranty.

 

[MrClean]

Do we know for sure this is a time-based limit rather than an RPM/Back-EMF issue? I’ve heard multiple people complain about the lack of oomph above 60, even from a steady cruise rather than a hard acceleration up to and past 60. It might even explain the faster trap speed of the Premium, which has a different gear ratio.

 

[dtbaker61]

Here you go.

Outside temp is 42 Degrees. Car was parked in the garage plugged in. Did a remote start for 10 minutes before these runs. Power meter was showing 1 gray bar of limitation at the start, so Not 100% full power but close.

I did multiple runs, charted the SoC, Speed, Power flow, and every temp sensor I could find that would be related.

2 runs I didn't let the gray bars clear from the power meter. You can see those by being limited at around 200kWh.

The main thing I'm seeing is the primary inverter does shoot up in temp quite a bit, but drops back down almost as quick.

Also attaching the spreadsheet file of the data if anyone wants to investigate a bit closer.

I will do this again later, and hopefully I can get the car to not have any limitation on the power meter for the next runs. And I'll try and be a little more consistent on what speed I get to and How quick I slow down. And If someone has something they'd like me to try or add to the testing, just let me know.

very interesting that the Inverter temps may be the most reactive.... also a good thing for possible chiller since that's a lot less mass to keep cool than the entire battery tray

what I suggest, in the name of science, is to limit the number of sensor inputs now so you can hopefully get the time scale on the readings to several per second.

I'd suggest just the HV battery current (or kw), and the inverter temps starting 'cold' with no prewarming, and making a couple back to back runs to see if the time duration of full current accelleration is exactly 5 seconds, or is reduced as inverters/coolant warm up.

i.e. with no pre-conditioning/warming, and left outside overnight, everything might start off at 50 degrees, and then after a couple back to back runs the coolant inlet temp might be closer to 90 and not cool the inverter as well. The hypothesis would be the first runs would have longer run at full current if the system is based on temp rather than pure timer.

 

[benk016]

very interesting that the Inverter temps may be the most reactive.... also a good thing for possible chiller since that's a lot less mass to keep cool than the entire battery tray

what I suggest, in the name of science, is to limit the number of sensor inputs now so you can hopefully get the time scale on the readings to several per second.

I'd suggest just the HV battery current (or kw), and the inverter temps starting 'cold' with no prewarming, and making a couple back to back runs to see if the time duration of full current accelleration is exactly 5 seconds, or is reduced as inverters/coolant warm up.

i.e. with no pre-conditioning/warming, and left outside overnight, everything might start off at 50 degrees, and then after a couple back to back runs the coolant inlet temp might be closer to 90 and not cool the inverter as well. The hypothesis would be the first runs would have longer run at full current if the system is based on temp rather than pure timer.

I definitely noticed a reduction in power every run at around 80mph. One of the runs I even started at 40mph, to see if it would behave any different, and it still cut power at around the same place.

I'm gonna let the car cool down for a bit, and try it again with a few less sensors. I also upped the frequency of data plots to like 10 per second to try and get more accurate data.

 

[dtbaker61]

I definitely noticed a reduction in power every run at around 80mph. One of the runs I even started at 40mph, to see if it would behave any different, and it still cut power at around the same place.

I'm gonna let the car cool down for a bit, and try it again with a few less sensors. I also upped the frequency of data plots to like 10 per second to try and get more accurate data.

the key that I am looking for is whether there is any difference in the duration of full power when the coolant is starting out dead cold (at 40-50 degrees) rather than steady state operating temp.

I suspect that once up to operating temp, the time it takes to warm and cool will be very consistant since the inlet temp of the coolant seems to stabilize and hold pretty steady once it is up to temp.

The only way we can see if 'chilling' extends the time will probably be just the first run, with no warm-up, left outside so everything is cold.


unless you are ready to wrap the inverter in a dry ice blanket......

 

[benk016]

OK, another 6 runs today. Turned up the logging frequency. This was with no pre-conditioning. Car in the garage, started it up drove the 1 mile to a back road, and ran these pretty much back to back. Still had 1 gray bar of power limitation in the power meter. Haven't been able to get that to go away yet.

 

[Scooby24]

definitely doesn't look to be a battery temp issue unless that HVB Temp isn't an accurate sensor.

 

[Kevin P]

Ben, can you track throttle position? I am interested in how the power tails off after the 5 seconds (or ~80mph, whichever comes first.) Obviously the kW flow is around 350 for the 5 seconds, but when it drops off really fast after that, how much of that is you lifting off the throttle and how much is power restrictions? I am guessing its all restrictions and drops to roughly 175 (by 50%) over the next several seconds, until its starts to level off.

Alternately, if its as simple as you are at 100% throttle until the sharp drop with kW goes to zero, that answers my question.

Interestingly, 350kW = 470hp.......

 

[Mach1E]

OK, another 6 runs today. Turned up the logging frequency. This was with no pre-conditioning. Car in the garage, started it up drove the 1 mile to a back road, and ran these pretty much back to back. Still had 1 gray bar of power limitation in the power meter. Haven't been able to get that to go away yet.

So it looks like the inverter temp spikes but only for literally a second or two and starts cooling off even while at full throttle?

Battery temps seem quite stable and in safe ranges.
The battery power output almost reads exactly like what I expect a Dyno would read.

350 kw for a few seconds (470hp)
Drops to 225 kw after 5 seconds (300 hp)
And slides to 175 kw by the end of the run (235 hp)

What speed were you going at the end of each run and about how long (time in seconds)?

Looks like it loses around 100 kw (135hp) minimum after the 5 seconds based on those runs.

Also 1 request: please try easing into the throttle instead of stabbing it. I’m curious if the inverter temp won’t spike that way and if the drop in power is less severe. My car feels faster easing into it vs stabbing for some reason.

 

[benk016]

What speed were you going at the end of each run and about how long (time in seconds)?

I think all these runs ended with me hitting between 95-100mph

Also 1 request: please try easing into the throttle instead of stabbing it. I’m curious if the inverter temp won’t spike that way and if the drop in power is less severe. My car feels faster easing into it vs stabbing for some reason.

I will try that tomorrow. I also want to try a few runs in unbridled extend just to see what those look like.



Just based on what I'm seeing, its looking more and more like its just a timed limitation over an actual sensor based limitation at this point.

 

[benk016]

Alternately, if its as simple as you are at 100% throttle until the sharp drop with kW goes to zero, that answers my question.

Interestingly, 350kW = 470hp.......

This is exactly right.

It is full throttle until you see it drop to below 0 because it starts using regen immediately as you let off the accelerator. Even with 1PD off, as soon as you let off, the power meter shows a very small amount of regen happening, and then it kicks up when you hit the brake pedal.

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