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Discussion Starter · #1 ·
Hello,

I own an ecochic of 10 000 miles. Bad luck or bad construction.....my drivetrain broke a week ago. I have to admit that its not cheap to change.

As I do have access to several tech and engineers because of my job, I would like to change it myself. However, I feel there are some basic steps to do to avoid collateral damage, such as unpluging HV batteries, etc.

Of course, Karma don't want to tell me those basic steps, as it is so complicated according to them. We are not talking about rebuilding a boeing 747, we just need removing and replacing a drivetrain on a car.

Does someone could help me with the major steps of changing my drivetrain ?

would be much appreciated

Tks, Michael
 

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Hello,

I own an ecochic of 10 000 miles. Bad luck or bad construction.....my drivetrain broke a week ago. I have to admit that its not cheap to change.

As I do have access to several tech and engineers because of my job, I would like to change it myself. However, I feel there are some basic steps to do to avoid collateral damage, such as unpluging HV batteries, etc.

Of course, Karma don't want to tell me those basic steps, as it is so complicated according to them. We are not talking about rebuilding a boeing 747, we just need removing and replacing a drivetrain on a car.

Does someone could help me with the major steps of changing my drivetrain ?

would be much appreciated

Tks, Michael
Generally speaking..Remove MSD underneath drivers side rear passenger seat then remove rear bumper and then close out panel and cables from inverter then the rear subframe. Pretty self explanatory here is a picture that may help.
 

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Discussion Starter · #3 ·
Tks for this input. Sorry for asking (I'm french), but what is the meaning of MSD ? Any care when we disconnect everything from the inverter ? Any other electrical stuff that I need to take care ?

On a mechanical stand point, I'll be ok. It is more stuff related to batteries that freak me out !

Tks
 

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Tks for this input. Sorry for asking (I'm french), but what is the meaning of MSD ? Any care when we disconnect everything from the inverter ? Any other electrical stuff that I need to take care ?

On a mechanical stand point, I'll be ok. It is more stuff related to batteries that freak me out !

Tks
MSD is the manual service disconnect which is the main fuse for the battery pack. This will "disable" the pack. It is an orange plug underneath the drivers side rear passenger seat. You will also want to disconnect the 12v plug on the passenger side front fender (inside the engine bay).

Once the MSD is removed, you can then safely disconnect the high voltage cables. You will still want to use a Volt meter and rubber gloves to measure the voltage at the cables to ensure that the pack has indeed been disabled prior to any HV work. Good Luck!
 

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Tks for this input. Sorry for asking (I'm french), but what is the meaning of MSD ? Any care when we disconnect everything from the inverter ? Any other electrical stuff that I need to take care ?

On a mechanical stand point, I'll be ok. It is more stuff related to batteries that freak me out !

Tks
You will find some useful information here, including the location of the MSD.
 

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Discussion Starter · #8 ·
Well, depend on the problem. It looks like to be a RDM problem. If so, won't touch the electric motors.

However, instead of changing the RDM for the new revero RDM, I might consider rebuilding it. I can't understand why Karma just waranty the new RDM for only a year. That indicates a lack of confidence on the part !

So' I'l see.
 

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Well, depend on the problem. It looks like to be a RDM problem. If so, won't touch the electric motors.

However, instead of changing the RDM for the new revero RDM, I might consider rebuilding it. I can't understand why Karma just waranty the new RDM for only a year. That indicates a lack of confidence on the part !

So' I'l see.
@hydroressources, There is a known weakness in the connection between the electrical motors and the RDM (search for the phrase "soft spline") which can be addressed in a couple of different ways. Even if your current failure is not caused by this weakness, as long as you have the RDM off the car, it would make sense to address this issue at the same time. Best solution is to get upgraded RDM and upgraded Motors as a single unit and swap them at the same time. I am not trying to spend your money for you, but spending strategically at this stage may help avoid future problems.
 

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Discussion Starter · #10 ·
Tks Fabulist for this input. That is very impressive how the engineers of Fisker did it wrong. That remain very basic mechanics, calculate the torque, the HP, acceleration and shear strength of metal parts. Rotation and torque are common stuff in several applications such as pumps and impeller.

Well, I will put all that out and check for the splines as well. If I see a problem, I'll try to find a way to weld or clip all that together instead of leaving some potential free space.

However, according to what I saw on previous post, noise on decel is more associated with the drivetrain. That is what I noticed before it broke. So that make sense to believe it is the drivetrain.

The post I read was from 2013. So far do you know if some found alternate ways to prevent failure, other then replacing the motors (another 8 000 $ I think)

Tks
 

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Tks Fabulist for this input. That is very impressive how the engineers of Fisker did it wrong. That remain very basic mechanics, calculate the torque, the HP, acceleration and shear strength of metal parts. Rotation and torque are common stuff in several applications such as pumps and impeller.

However, according to what I saw on previous post, noise on decel is more associated with the drivetrain. That is what I noticed before it broke. So that make sense to believe it is the drivetrain.
Not trying to make excuses for Fisker engineers, but I think Fisker leaned very heavily on suppliers to design a lot of the sub-systems. But of course, that decision itself has consequences also.

Your diagnosis is logical, I was just wanted to make you aware of this issue to look into it while you have the RDM apart, because it has been some time since we had discussed it on the forum, and you may not have seen it. One solution applies prophylactically by Fisker service techs was to apply Loctite at the interface to reduce the lash between the gears.

Some of the experts have also tried working with machinists to forge and make hardened steel parts to prevent damage. Check with @FiskerPhilly and @Harleyguy about that.
 

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Discussion Starter · #12 ·
One more questions regarding this topic: I started opening all my car. However, I noticed a series of cooling line. There is one linked to the combustible engine, one or a bunch linked to the inverters and the batteries and one linked to the drivetrain. Of course, I will have to disconnect at least one at some point.

Any advise regarding this aspect ? What is the effect of air in the cooling system ? Before to touch it, I would like to have some feedback.

Tks again
 

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Discussion Starter · #13 ·
Spline and RDM

Are you just swapping out a complete RDM unit with motors or are you rebuiding the motors and RDM?
Finally, I got everything out of my car, and as you and Fabulist was thinking, the problem is due to erosion of the splines of the traction motors. Of course the male part of the spline in the RDM is also affected.

Regarding the motors, I think I can rebuilt it. We just have to remove the splines and replace by new one. However, I read many post on hard and soft spline. To what I understand, Soft spline are related to soft steel, and hard to tempered steel. Many noticed that soft and hard splines failed, which is normal. Tempered steel does not have higher torsion and shear resistance: it is just harder in terms of hardness. It is then probably less susceptible to erosion, but it will shear if the torque is too high.

I would like to know if some of you succeed to rebuit the RDM and the motors and/or if some of you have something to offer. In terms of splines, the best is to rebuilt with duplex stainless steel alloy (17-4PH) this alloy is about 3 times more resistant for torsion. This what I intend to do with the motor. However, for the RDM, if someone has stuff to propose, I would like to hear about. Rebuilding it might be more complex.

Cheers
 

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Finally, I got everything out of my car, and as you and Fabulist was thinking, the problem is due to erosion of the splines of the traction motors. Of course the male part of the spline in the RDM is also affected.

Regarding the motors, I think I can rebuilt it. We just have to remove the splines and replace by new one. However, I read many post on hard and soft spline. To what I understand, Soft spline are related to soft steel, and hard to tempered steel. Many noticed that soft and hard splines failed, which is normal. Tempered steel does not have higher torsion and shear resistance: it is just harder in terms of hardness. It is then probably less susceptible to erosion, but it will shear if the torque is too high.

I would like to know if some of you succeed to rebuit the RDM and the motors and/or if some of you have something to offer. In terms of splines, the best is to rebuilt with duplex stainless steel alloy (17-4PH) this alloy is about 3 times more resistant for torsion. This what I intend to do with the motor. However, for the RDM, if someone has stuff to propose, I would like to hear about. Rebuilding it might be more complex.

Cheers

Try 58-62 HRC made out of 8625h cold rolled if possible
 
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