Powertrain questions

[ChasingCoral]

Yeah, I read somewhere that the lightning has two different gear ratios front/rear as well.

This wouldn't surprise me. The Mach E has different gear ratios on the front and rear.

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[ChasingCoral]

This is a spot on comment.

All this talk of probably not being able to flat tow brings up another question: surely the lightning will have a neutral position on its gear selector, what will this actually do? Will I still be able to put it in neutral and push it out of the way if it’s dead? Will I be able to spin a wheel freely if I jack up the vehicle, as if to change a tire? If these situations work, why wouldn’t you be able to flat tow in neutral?

The Mach E has a neutral for being pulled through car washes, towed not flatbeds, and other emergency situations. However, it is designed for slow speed and short distance use only, not flat towing.

 

[Brian Head Yankee]

You don't really need a classic "neutral" to push it or rotate a wheel. You only need a button to release the brake assuming that the park brake is automatic.

Got beat to the punch with the comment above me that was posted as I typed

 

[superds]

The Mach E has a neutral for being pulled through car washes, towed not flatbeds, and other emergency situations. However, it is designed for slow speed and short distance use only, not flat towing.

So what are the technical limitations that won’t allow flat towing with this neutral mode?

 

[Brian Head Yankee]

I can only guess that there is a mechanical lock up when power is lost. It needs voltage to get out of park.

 

[Pedaldude]

Permanent magnet motors are always going to be either motors when supplied with the correct voltage or generators when they are spun. If the energy being generated has nowhere to go, it can overheat or damage something in the system and if the electrical current flow isn't balanced properly it will overheat and damage the windings or insulation of the motor.

Even AC motors and generators, which tend to be more robust than their DC counterparts can suffer permanent damage under the right (wrong) circumstances.

Electricity and magnetic fields can do wacky stuff and since it can't be seen most of the time it's one of the harder things to conceptualize.

Off the current topic, another thing that some people sometimes falsely believe is that a battery is safe. Though the Samsung Galaxy Note7 helped dispel that myth. As far as I know, nobody has been killed wrenching on an electric car yet, plugging into a charger or rescuing someone from a crashed EV. I fear it's an inevitability though just as someone has already been killed by a self-driving car.

 

[Brian Head Yankee]

Are you here as our protective father? You work for Dodge? Care to share your credentials in all things EV?

 

[superds]

Permanent magnet motors are always going to be either motors when supplied with the correct voltage or generators when they are spun. If the energy being generated has nowhere to go, it can overheat or damage something in the system and if the electrical current flow isn't balanced properly it will overheat and damage the windings or insulation of the motor.

Even AC motors and generators, which tend to be more robust than their DC counterparts can suffer permanent damage under the right (wrong) circumstances.

Electricity and magnetic fields can do wacky stuff and since it can't be seen most of the time it's one of the harder things to conceptualize.

Thank you for the explanation.

 

[ChasingCoral]

Off the current topic, another thing that some people sometimes falsely believe is that a battery is safe. Though the Samsung Galaxy Note7 helped dispel that myth. As far as I know, nobody has been killed wrenching on an electric car yet, plugging into a charger or rescuing someone from a crashed EV. I fear it's an inevitability though just as someone has already been killed by a self-driving car.

Quite true but more ICE vehicles catch fire each year than BEVs -- even on a per mile driven basis. 150 ICE car fires every day.

 

[Theo1000]

I wonder what made them go for permanent magnets on the motors. There are some advantages to induction motors even if fractionally less efficient including flat tow with some careful engineering.

 

[ChasingCoral]

I wonder what made them go for permanent magnets on the motors. There are some advantages to induction motors even if fractionally less efficient including flat tow with some careful engineering.

Significant advantages is price, efficiency, and power delivery. Sure, you can find efficient induction motors but they are expensive. That was what Ford said when they made the same decision for the Mustang Mach E.

 

[MickeyAO]

Quite true but more ICE vehicles catch fire each year than BEVs -- even on a per mile driven basis. 150 ICE car fires every day.

I actually talk about this when giving tours of my labs...I also say "one electric vehicle fire anywhere in the world will be front-page news.'

 

[MickeyAO]

Off the current topic, another thing that some people sometimes falsely believe is that a battery is safe. Though the Samsung Galaxy Note7 helped dispel that myth. As far as I know, nobody has been killed wrenching on an electric car yet, plugging into a charger or rescuing someone from a crashed EV. I fear it's an inevitability though just as someone has already been killed by a self-driving car.

EVs have contactors that will isolate the traction battery. There are simple tests with a voltmeter to let you know if something is seriously wrong. There are first responder websites that will let you know how to 'safe' the vehicle. I review these all the time before I start to take apart an EV, and have even hosted the local fire stations on what to watch for when coming across an EV (DON'T CUT AN ORANGE WIRE!). It's a little more difficult when the vehicle I have to take apart in two weeks is not available in the US (ID3).

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