Discovered: GTPE Delivers 5 Seconds of Full Power on Acceleration Then Reduces Battery Power to Limit Heating

[voxel]

In the Outofspec review of the GTPE, Kyle was not able to get into unbridled extreme mode after hooning the car a bit. It kept overheating and telling him that the mode is not accessible. Is this the reason for it? Is it the same thing or different?

Somebody needs to have a OBD-II device report the battery temps but it does sound like battery thermal management.

The reported battery IR (36 milliOhms) is just okay to me. The charging curve is pathetic (sub 1C) from start to end so there is something odd.

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[buzznwood]

Somebody needs to have a OBD-II device report the battery temps but it does sound like battery thermal management.

The reported battery IR (36 milliOhms) is just okay to me. The charging curve is pathetic (sub 1C) from start to end so there is something odd.

I managed to do a couple of 1/4 runs over the weekend to time with my racebox I stopped after each one and after each run the front shutters where closed, if it was a toasty battery you would expect them open with audile fan noise

It the thermals really are are an issue preventing even a single full power from 0 to its top speed then there right there is some shonky 1960 levels of poor engineering where overheated in traffic due to inadequate cooling was common and Fords engineers need to hang their heads in shame.

It is not like we even have the full power as the combined output of both motors is 562hp so 480hp is being very conservative.

 

[voxel]

I managed to do a couple of 1/4 runs over the weekend to time with my racebox I stopped after each one and after each run the front shutters where closed, if it was a toasty battery you would expect them open with audile fan noise

It the thermals really are are an issue preventing even a single full power from 0 to its top speed then there right there is some shonky 1960 levels of poor engineering where overheated in traffic due to inadequate cooling was common and Fords engineers need to hang their heads in shame.

It is not like we even have the full power as the combined output of both motors is 562hp so 480hp is being very conservative.

Fans? These batteries are liquid cooled beasts. There's a complicated cooling system to prevent them from going over 50C for long periods... heck 40C isn't great either.

Again, we need battery temp measurements from the vehicle sensors. There's too much guessing going on. The Ioniq 5 and EV6 have battery thermal issues too. Those 800V cars push out serious power (more than a Mach-E) but when the battery is hot (50C) they drastically throttle power down to almost nothing (60 kW from Bjorn's video). Ford isn't some advanced battery tech company like Tesla. This is their first rodeo at a high performance EV.

 

[Frankie]

Fans? These batteries are liquid cooled beasts.

ICE engines are also generally liquid cooled.

And like the Mach-e, they usually have fans to aid in the cooling of that liquid

 

[sukhoi_584th]

Has anyone driven theirs in the mountains? The reports a couple pages back that even ~60 mph flat cruising only allows a couple seconds of peak passing power before limiting, makes me concerned about passing power when cruising at 55 mph on sustained uphill grades. It's a heavy vehicle and 250 hp or whatever isn't going to work.

 

[Kevin P]

The Mach E definitely has fans. I had the car in park, but left on, and standing outside it; the front vents were open, you could hear the fans, and you could feel airflow with your hand by the vents. This was after a slow drive. I think though that if you turn the car off, it shuts all that down, unless its plugged in.

 

[voxel]

ICE engines are also generally liquid cooled.

And like the Mach-e, they usually have fans to aid in the cooling of that liquid

Sure. No argument there.

To me the liquid cooling needs to be effective while driving the car (and also charging).... a fan that blares up when the car is idle or stopped is not a proper test. i.e 40C isn't deadly to a battery at rest as it will naturally cool. It's 40C PLUS a discharge (accelerating) that causes damage.

 

[voxel]

The Mach E definitely has fans. I had the car in park, but left on, and standing outside it; the front vents were open, you could hear the fans, and you could feel airflow with your hand by the vents. This was after a slow drive. I think though that if you turn the car off, it shuts all that down, unless its plugged in.

Fans are not the issue. My ID.4 has fans full blare when DC charging. How effective is the liquid cooling when the battery is put under a 1C/2C load when accelerating?

 

[buzznwood]

Fans? These batteries are liquid cooled beasts. There's a complicated cooling system to prevent them from going over 50C for long periods... heck 40C isn't great either.

Again, we need battery temp measurements from the vehicle sensors. There's too much guessing going on. The Ioniq 5 and EV6 have battery thermal issues too. Those 800V cars push out serious power (more than a Mach-E) but when the battery is hot (50C) they drastically throttle power down to almost nothing (60 kW from Bjorn's video). Ford isn't some advanced battery tech company like Tesla. This is their first rodeo at a high performance EV.

Err how do you expect air to move over a liquid to air heat exchanger with a stationary vehicle and no fans? The Ioniq 5 and EV6 issues that I have seen people experience are when the battery is toasty hot after it has just finished a DCFC session they are not being prevented from doing full power runs under normal circumstances, besides if it is battery thermals then the GT / GTPE must have the most amazing cooling system ever as after a few seconds as if by magic full power is restored, no toasty battery will cool down that fast.

 

[voxel]

Err how do you expect air to move over a liquid to air heat exchanger with a stationary vehicle and no fans? The Ioniq 5 and EV6 issues that I have seen people experience are when the battery is toasty hot after it has just finished a DCFC session they are not being prevent from doing full power runs under normal circumstances, bedsides if it is battery thermals then the GT / GTPE must have the most amazing cooling system ever as after a few seconds as if by magic full power is restored, no toasty battery will cool down that fast.

"magic full power is restored" - so reports say you can full throttle say 10-30 seconds later?

Yes the Ioniq 5 and EV6 issues are after extreme DC charging (1.9C average - 150+ kW... MME barely hits 1C) which heats up the battery just like discharging. The car would not allow full throttle (only partial) for a few minutes after charging while the battery cooled.

No argument on a stationary vehicle needing a fan but an exposed radiator or plate (underneath the car?) should dissipates battery heat when moving. It's a giant AC system (VW ID.4 uses G13/G12 coolant in their pumps - don't know anything about the MME cooling system).

 

[dtbaker61]

Sure. No argument there.

To me the liquid cooling needs to be effective while driving the car (and also charging).... a fan that blares up when the car is idle or stopped is not a proper test. i.e 40C isn't deadly to a battery at rest as it will naturally cool. It's 40C PLUS a discharge (accelerating) that causes damage.

exactly...

Lithium batteries have very low internal resistance compared to Lead-acid, but at very high current passing thru cell, the resistance turns into heat in the heart of the cell.... which takes TIME to transfer to the outside of the cell, and dump heat.

EDragsters have extended output by using 'pouch' cells that are thin and allow internal fluid to circulate.... and then using various methods to supercool the fluid during 'high current' to hold the internal temp as close to optimal (70 deg F) as possible.

this is why I go back to the most effective mod being a COOLANT enhancement to extend peak power delivery.

 

[dtbaker61]

Somebody needs to have a OBD-II device report the battery temps but it does sound like battery thermal management.

there are plenty of OBD apps that will let you see various temps interactively on your phone via BT, available right now, and pretty cheap. Just not displayed on the instrument panel where you might hope. ah well, *most drivers* just want an idiot light when something goes bad.

I bought Viecar OBD, and used CarScanner app to capture some voltage and current data.... I REALLY want to see actual kW in/out interactively onscreen... but sadly waiting for Ford to display actual numbers. I'm the kind of person who likes the actual numbers rather than green-yellow-red.

I will bet that if you took a look at battery and motor temps (interactively), it would be easy to figure out when power it reduced to enable coolant to keep up with heat load.... but you can't DO anything about it unless you add additional cooling, or hack parameters... which could result in severely shortening battery or motor life.

 

[buzznwood]

"magic full power is restored" - so reports say you can full throttle say 10-30 seconds later?

There is a limit if you do a run from stand still you get a full power on the power meter bar then after around the 5 seconds mark it pretty much gets halved with a greyed out unavailable region appearing. If you lift at that point you can see the unavailable region slowly get removed so you can stamp on the go pedal get full power until after x seconds its get nobbled once again lift off and it will do the same. However the unavailable region and removal time changes based on speed.

Having a safety protection algorithm cutting in is fine, however there are a couple of issues I have with this,

The first I think this power bar needs to much bigger, or at least done as a circular gauge around the speedometer when it can be easily made much larger without taking up much dash footprint so people can easily see the current state of any power limitations especially those of us with old man eyes lol.

The second is looking at this from a pure engineering perspective this really comes across as a quick software band aid solution being implemented to account for deficiencies in mechanical engineering to allow marketing to tick a few check boxes rather than properly engineering a solution to allow performance objectives to be meet, there could of course be no issues at all with the hardware and it could easily let rip with full power for extended periods of time, which then just begs the question of why have so little faith in the engineering and apply a limit to it.

 

[phidauex]

Fans? These batteries are liquid cooled beasts. There's a complicated cooling system to prevent them from going over 50C for long periods... heck 40C isn't great either.

Again, we need battery temp measurements from the vehicle sensors. There's too much guessing going on. The Ioniq 5 and EV6 have battery thermal issues too. Those 800V cars push out serious power (more than a Mach-E) but when the battery is hot (50C) they drastically throttle power down to almost nothing (60 kW from Bjorn's video). Ford isn't some advanced battery tech company like Tesla. This is their first rodeo at a high performance EV.

No guessin’ here - I’ve been taking many logs of system performance and battery and coolant temperatures. I’ve never seen the battery over 32C and that was after two hours of fast ascending many thousands of feet of elevation. Many of us have been collecting data for a while now.

Check out the data logs here if you want to take a closer look. I periodically post more: https://www.macheforum.com/site/threads/driving-dynamics-and-charging-data-files.8473/

The MachE does have active cooling for the battery system, the nominal inlet temperature at the battery cold plates tends to be around 58F. Each battery module is in a compressed plastic enclosure with an independent cold plate, which is a good design. There is a radiator behind the front lower grill inlets (which open and close as needed), and a supplemental fan to bring in extra air if needed or when charging.

The issue with the 5 second time isn’t overall pack temperature, I’m sure, it is a combination of localized heating and the high overall C-rate.

Also, just to be clear, the MachE does charge at 1.5C at the beginning of the charge cycle, then drops to 1.2 for much of the cycle, and then tapers down to 0.7 or so before hitting the cliff at 80% SOC. It is a bit conservative compared to some other makers, but we are hoping for improvements there.

Has anyone driven theirs in the mountains? The reports a couple pages back that even ~60 mph flat cruising only allows a couple seconds of peak passing power before limiting, makes me concerned about passing power when cruising at 55 mph on sustained uphill grades. It's a heavy vehicle and 250 hp or whatever isn't going to work.

I’ve ascended 6000 ft at 85+mph and had no thermal issues in my E4X - as I mentioned above I’ve never seen a battery temp over 32C and that was after two hours of aggressive driving at high elevation. Remember that high elevation reduces cooling system performance (less air mass to shed heat into).

I’ve had a few concerns about the front motor temp going too high, since it is the least cooled active component, but everything else, battery, rear motor, and both inverters stay very well cooled, better than I was anticipating.

Check out a few data logs here, and I’m hoping to collect more soon that include the min/max cell temp values which can be a good way of identifying differential cooling problems (finding hot spots). https://www.macheforum.com/site/threads/driving-dynamics-and-charging-data-files.8473/

Ultimately there will always be some limitation on power output vs duration as long as we are on the same basic Li chemistries - my main question is whether that limitation is reasonable or overly conservative, and if there are things that could be done to improve it, such as make it temperature sensitive, or make it a gentler taper rather than a big drop.

 

[voxel]

Also, just to be clear, the MachE does charge at 1.5C at the beginning of the charge cycle, then drops to 1.2 for much of the cycle, and then tapers down to 0.7 or so before hitting the cliff at 80% SOC. It is a bit conservative compared to some other makers, but we are hoping for improvements there.

From this data, it’s only 1C for 30% of the charging curve which seems far too conservative. It has a very brief spike of 1.5C at low SOC. This is ultra conservative compared to the E-GMP which chooses to be aggressive in charging at 2.5C and averages 1.9C. The lowly ID.4 even has a faster raw kW rate (and also higher charging C rate because of the smaller battery).

https://insideevs.com/news/492727/ford-mustang-mache-fast-charging-analysis/

Good to know battery temps are low because that implies there is performance head room to unlock.

Will examine your other data - thanks for the link. I see the system pushing out 200 kW around 50mph but has anybody graphed there power output to 100mph? Does the power stay at 2C / 200+ kW or does drop unexpectedly (whether by Ford design or some overheating of electronics)?

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