Why has the sr AWD version the same HP insteed of the RWD sr version?

SnBGC

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It's not the "78 kWh" part that limits it. It's the "288 cells" part.

The Standard Range pack is a "3P96S" configuration, with 3 parallel banks of 96 cells in series, for a total of 288 cells.
The Extended Range pack is a "4P94S" with 4 parallel banks of 94 cells in series, for a total of 376 cells.

We can assume the same cells are used in both packs, so the cells have a common maximum discharge current.

The SR pack has {CELL DISCHARGE POWER} * 288 cells = 190 kW pack discharge limit
The ER pack has {CELL DISCHARGE POWER} * 376 cells = ? kW discharge limit

Assuming 190 kW is the limit, and assuming the system is at 400V that would yield:

190,000W/400V = 475A
475A / 288 cells = 1.65A /cell

If we assume that's right, we can then get the theoretical discharge limit for the ER pack:

1.65A * 376 cells = 620 A
620A * 400V = 248,000W

Looking at the Mach-E ER AWD, the total system power is: 248 kW.

We know the PDU is capable of 210 kW (ER RWD). We know there are two SDUs, a GT and a non-GT. Neither SDU's power has been directly confirmed, but adding the non-GT SDU to the ER pack only bumps system power by 38 kW, so either that's the world's smallest SDU, or Ford is throttling the ER AWD.

Why would that be the case if the GT's ER battery can support 342 kW peak discharge? That's an interesting question. My theories are that:

1.) Ford is upgrading the cell inside the GT pack
2.) that the actual current limit is not the cell, but the internal wiring inside the pack, which would be upgraded for the GT
and/or
3.) that Ford is software limiting the non-GT pack, or possibly any combination of the three.

This is just rough "non-scientific" math to get a sense of why things are this way, but they're things we can easily assume from the public specs sheet, and a healthy bit of inference and speculation.
The front motor is different in the GT vs the other AWD models. (I am sure you are aware of this already but just repeating it here for others that might come along later...)

The front motors are usually limited for a variety of reasons. Even though they may be capable of a certain output, they are controlled to minimize torque steer, traction limits, traction vectoring etc. The very best AWD system that I have driven is the one in the Jaguar I-Pace. The Mach E is also pretty good.

I have no idea how Ford is going to solve that problem in the GT. They must have a pretty good method planned because the preliminary figures are quite impressive.
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I know that but I try to understand why with 2 motors instead of one the standard range AWD Mach-E has the same horsepower than the RWD standard range Mach-E (and even less horsepower than the RWD long range Mach-E that has only one motor).
By no means am I a battery expert, but...

In order for the motor to produce power, it has to receive that power from the battery.

The battery is pretty much constant voltage. How much power it can deliver is based on how much current it can deliver. Each array in a battery provides the same voltage, and some current. The current from the arrays are added together. The 4 array battery (extended) should be able to push out much more current than the 3 array (standard) battery. A third more.

Look at the "cold cranking amps" of different batteries. Same size battery, even the same total kWh, just capable of different power outputs.
 

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The front motor is different in the GT vs the other AWD models. (I am sure you are aware of this already but just repeating it here for others that might come along later...)

The front motors are usually limited for a variety of reasons. Even though they may be capable of a certain output, they are controlled to minimize torque steer, traction limits, traction vectoring etc. The very best AWD system that I have driven is the one in the Jaguar I-Pace. The Mach E is also pretty good.

I have no idea how Ford is going to solve that problem in the GT. They must have a pretty good method planned because the preliminary figures are quite impressive.
Right - the GT's SDU is different, but Ford hasn't actually broken down what the stats on each SDU are, the only thing we know is that the ER AWD is 210 kW, so we can assume that the PDU is 210 kW.

When the PDU goes in the SR, it's capped to 190 kW by the battery, and when the SDU is added to make a SR AWD, the PDU gets even less power, because it shares it with the SDU, but the overall system torque changes due to the different gearing of the SDU.

Without Ford giving us a part-number breakdown of SDU/PDU specs, we can only guess.
 

RonTCat

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Right - the GT's SDU is different, but Ford hasn't actually broken down what the stats on each SDU are, the only thing we know is that the ER AWD is 210 kW, so we can assume that the PDU is 210 kW.

When the PDU goes in the SR, it's capped to 190 kW by the battery, and when the SDU is added to make a SR AWD, the PDU gets even less power, because it shares it with the SDU, but the overall system torque changes due to the different gearing of the SDU.

Without Ford giving us a part-number breakdown of SDU/PDU specs, we can only guess.
Base: PDU >> SDU
GT: PDU = SDU
 

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Base: PDU >> SDU
GT: PDU = SDU
Correct, but 210 kW (the PDU's peak in the ER RWD) + 210 kW does not equal the GT's 342 kW output.

So even in the GT, there's power management going on and the motors are not each operating at their individual peak outputs simultaneously.

That's what I'm saying, we can't actually see the power per axle unless Ford divulges it.
 
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SnBGC

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By no means am I a battery expert, but...

In order for the motor to produce power, it has to receive that power from the battery.

The battery is pretty much constant voltage. How much power it can deliver is based on how much current it can deliver. Each array in a battery provides the same voltage, and some current. The current from the arrays are added together. The 4 array battery (extended) should be able to push out much more current than the 3 array (standard) battery. A third more.

Look at the "cold cranking amps" of different batteries. Same size battery, even the same total kWh, just capable of different power outputs.
I think you are on the right path. Lots of information that we don't have to fill in the blanks but yeah....I think you have it down correctly. The conversion from DC to AC to power the motors is probably where the major obstacle occurs at the moment.
 

RonTCat

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I think you are on the right path. Lots of information that we don't have to fill in the blanks but yeah....I think you have it down correctly. The conversion from DC to AC to power the motors is probably where the major obstacle occurs at the moment.
Thermal management of the battery is likely also occurring.
 

SnBGC

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Thermal management of the battery is likely also occurring.
On the list of things that I will collect data on as soon as I am able to connect to the on board systems and monitor the sensors. My suspicion is the thermal management isn't in issue on the first run or two but comes into play after that point. It will be interesting for sure...
 

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So even in the GT, there's power management going on and the motors are not each operating at their individual peak outputs simultaneously.
Not to mention that motors can operate above their peak rated capacity for short periods of time.
 

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It's not the "78 kWh" part that limits it. It's the "288 cells" part.

The Standard Range pack is a "3P96S" configuration, with 3 parallel banks of 96 cells in series, for a total of 288 cells.
The Extended Range pack is a "4P94S" with 4 parallel banks of 94 cells in series, for a total of 376 cells.

We can assume the same cells are used in both packs, so the cells have a common maximum discharge current.

The SR pack has {CELL DISCHARGE POWER} * 288 cells = 190 kW pack discharge limit
The ER pack has {CELL DISCHARGE POWER} * 376 cells = ? kW discharge limit

Assuming 190 kW is the limit, and assuming the system is at 400V that would yield:

190,000W/400V = 475A
475A / 288 cells = 1.65A /cell

If we assume that's right, we can then get the theoretical discharge limit for the ER pack:

1.65A * 376 cells = 620 A
620A * 400V = 248,000W

Looking at the Mach-E ER AWD, the total system power is: 248 kW.

We know the PDU is capable of 210 kW (ER RWD). We know there are two SDUs, a GT and a non-GT. Neither SDU's power has been directly confirmed, but adding the non-GT SDU to the ER pack only bumps system power by 38 kW, so either that's the world's smallest SDU, or Ford is throttling the ER AWD.

Why would that be the case if the GT's ER battery can support 342 kW peak discharge? That's an interesting question. My theories are that:

1.) Ford is upgrading the cell inside the GT pack
2.) that the actual current limit is not the cell, but the internal wiring inside the pack, which would be upgraded for the GT
and/or
3.) that Ford is software limiting the non-GT pack, or possibly any combination of the three.

This is just rough "non-scientific" math to get a sense of why things are this way, but they're things we can easily assume from the public specs sheet, and a healthy bit of inference and speculation.
Thank you very much! I will read this again and again.
 

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I finally understood that the battery limits the HP but what I still don't understand is why is a 78 kWh battery is a limiting factor? When you compare the competition, most have 75-80 kWh batteries and has much more HP and torque than the Mach-E (Volvo, Polestar, Tesla, Jaguar, etc.).

The Model 3 Performance is believed to have around 450 horsepower despite a 75 kWh battery.
Polestar/Volvo also has a 78 kWh battery but they get 408 HP (and 487 lb-ft of torque). I understand that they have a more powerful motor but with 428 lb-ft of torque, I don't understand why the Mach-E has only 266 HP

So the real question is why the Mach-E is so limited with a 78 kWh battery? The math doesn't work
They are being very conservative until they see the operating limits of the battery system. The battery warranty for California, and I believe some other ZEV states is 8 years/100000 miles. Until they can get stats that tell them how the battery works through that kind of a period, then they won't give all the power that is actually available from the battery.

I think the Tesla Model 3 had at least 2 or 3 updates in power and range since it came out, this is based on getting data and determining how much battery output can be provided without excess degradation over time.

Corrected post, had wrong warranty period listed.
 
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ab13

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The battery warranty is 8 years/100k miles in all states. The 10 year requirement in ZEV states does not apply to full EVs (only PHEVs).
Thanks, I will correct my post. PHEV get the longest warranty, 15 years on major drivetrain components.
 

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Pure HP and torque mean in a sense not much, what I'm anxiously waiting to see (unless it has been published somewhere but I haven't found it) is the weight of the version version.

RWD-SR, RWD-ER, AWD-SR and AWD-ER, as well maybe later the version sub variants like Select vs Premium vs CR1 of these different powertrain/battery setup

There may be less HP on the RWD-SR but what's the difference on the lbs/HP compared to a RWD-ER or a AWD-ER for example

Obviously the AWD-ER would seem to have the best numbers, but given that the AWD adds weight and the ER adds weight, what's the net gain on a lbs/HP ratio, that would be interesting to know.
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