I'll be posting a video soon but with the setup in the photo (which is pretty inefficient) I was able to set the current to 3A @ 36V and the power steering worked fine. When turning the wheel the current rose to 6 or 7A but fell back to 3A immediately.
I say inefficient because an alternator is not efficient as a purpose made motor. I suspect a suitable motor could bring the current drain down to between 3/4 and 2/3 of these figures and the ebike controller I used is the cheapest available so not efficient either.
The one caveat to bear in mind is there is no weight on the front of the car so I suspect a completed conversion will draw more current when turning the wheel than it is now. The other thing is the ebike controller was not trying to maintain the speed of the motor, it was only trying to maintain the throttle position so a better setup might draw significantly more current when turning the wheel.
However it proves that this is a possible solution and if you choose your motor and controller correctly I see no reason why ac couldn't be incorporated.
Whether it would make more sense to source a 12V motor suitable and drive it from the 12V system or go with a totally separate high voltage system like this one I'll leave you guys to decide.
 
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Alibro said:
I'll be posting a video soon but with the inefficient setup in the photo I was able to set the current to 3A @ 36V and the power steering worked fine. When turning the wheel the current rose to 6 or 7A but fell back to 3A immediately.
I say inefficient because an alternator is not efficient as a motor. I suspect a suitable motor could bring the current drain down to between 3/4 and 2/3 of these figures and the ebike controller I used is the cheapest available so not efficient either.
The one caveat to bear in mind is there is no weight on the front of the car so I suspect a completed conversion will draw more current when turning the wheel than it is now. The other thing is the ebike controller was not trying to maintain the speed of the motor, it was only trying to maintain the throttle position so a better setup might draw significantly more current when turning the wheel.
However it proves that this is a possible solution and if you choose your motor and controller correctly I see no reason why ac couldn't be incorporated.
Whether it would make more sense to source a 12V motor suitable and drive it from the 12V system or go with a totally separate high voltage system like this one I'll leave you guys to decide.
Click to expand...

I think I'd use a higher voltage than 12 Volts Ali.
The reason would be reduced current needed by the PS motor, which is easier to control and doesn't need such thick wiring.

If you use a 36 Volts, then a 10 Amp draw is the equivalent of 360 Watts.
The same 360 Watts @ 12V would be 30 Amps, which would mean heavy wiring and potentially a larger 12 V DC to DC converter to power the additional steer motor.

I know what you're saying about the alternator not being super efficient as a motor, but it can't be too bad, if you saw 7 Amps @ 36 Volts, basically you're steering the car for 300 Watts of energy, and only burning ~90 Watts idling, which is nothing really. The TRW pump is using considerably more than that, and is also really noisy, which would put me off it anyway.
 
Another + for the alternator/motor is its robust, with large bearings and thick windings, which are designed to provide a long working life in the harsh environment of a vehicle engine bay.
You just need to power it at a constant speed under load, which means some form of encoder is needed, but it should be a robust PS solution.
 
Were the wheels on the ground or in the air?? PS design needs to be able to stand someone turning wheels when stationary without melt down!!
 
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andyfreelandy said:
We're the wheels on the ground or in the air?? PS design needs to be able to stand someone turning wheels when stationary without melt down!!
Click to expand...
Yes and no Andy
You're 100% right to point this out and the full answer is the car is on the ground but has no engine so the resistance is much smaller than it would normally be. I'm expecting the current drain when turning the wheels to be a bit higher with a full EV drivetrain and batteries on board. ;)
 
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!0
Nodge68 said:
I think I'd use a higher voltage than 12 Volts Ali.
The reason would be reduced current needed by the PS motor, which is easier to control and doesn't need such thick wiring.

If you use a 36 Volts, then a 10 Amp draw is the equivalent of 360 Watts.
The same 360 Watts @ 12V would be 30 Amps, which would mean heavy wiring and potentially a larger 12 V DC to DC converter to power the additional steer motor.

I know what you're saying about the alternator not being super efficient as a motor, but it can't be too bad, if you saw 7 Amps @ 36 Volts, basically you're steering the car for 300 Watts of energy, and only burning ~90 Watts idling, which is nothing really. The TRW pump is using considerably more than that, and is also really noisy, which would put me off it anyway.
Click to expand...
Nodge68 said:
Another + for the alternator/motor is its robust, with large bearings and thick windings, which are designed to provide a long working life in the harsh environment of a vehicle engine bay.
You just need to power it at a constant speed under load, which means some form of encoder is needed, but it should be a robust PS solution.
Click to expand...
100% John
It works well enough, has the correct pulley to match the PS pump, is easy to bolt to the PS pump, as you say it's robust, it should be easy to rig up a battery big enough to last as long as the main HV battery and the battery charger can easily be powered from the main HV charger connector.
If I can find a suitable motor at a reasonable price I might go that way but otherwise I'll stick with the altymotor.
 
Alibro said:
!0


100% John
It works well enough, has the correct pulley to match the PS pump, is easy to bolt to the PS pump, as you say it's robust, it should be easy to rig up a battery big enough to last as long as the main HV battery and the battery charger can easily be powered from the main HV charger connector.
If I can find a suitable motor at a reasonable price I might go that way but otherwise I'll stick with the altymotor.
Click to expand...


I like the way that works Ali. It's the very essence of a home brew EV conversion. :)
 
Nice system Ali, but FWIW, because pressure, and thus vacuum, is "omnipresent", you can put the vacuum sensor anywhere between the one way valve and the servo (the part of the master cylinger that you couldnae mind the name of) - making it easier to "package" up, which will hopefully make your life easier in the installation?
 
Alibro said:
This is how I plan to provide a vacuum for the brake boost.
Click to expand...


Excellent Ali. You're moving forward faster than me. :oops:

The vacuum sensor will connect straight to the servo on the standard servo connection. This will then be where Audi intended it to be, making the plumbing pretty easy to achieve. In reality it won't make a whole lot of difference where it goes, but why mess with making home made pipe connections, if Audi have already done a majority of the work for you. The sensor itself can be mounted on a simple bracket in a nearby location, giving an OE look. ;)

I'd actually mount the vacuum pump to the Leaf motor on some form of bracket, as the mass of the Leaf motor, will damp out most of the noise from the vacuum pump.

Don't mount it on a part of the body if you can avoid it, as the body will act like a sound board, and amplify the noise.
 
Nodge68 said:
Excellent Ali. You're moving forward faster than me. :oops:

The vacuum sensor will connect straight to the servo on the standard servo connection. This will then be where Audi intended it to be, making the plumbing pretty easy to achieve. In reality it won't make a whole lot of difference where it goes, but why mess with making home made pipe connections, if Audi have already done a majority of the work for you. The sensor itself can be mounted on a simple bracket in a nearby location, giving an OE look. ;)

I'd actually mount the vacuum pump to the Leaf motor on some form of bracket, as the mass of the Leaf motor, will damp out most of the noise from the vacuum pump.

Don't mount it on a part of the body if you can avoid it, as the body will act like a sound board, and amplify the noise.
Click to expand...
Lots of good points here John but the sensor came with the pipe work already on it, I just cut it back a bit as it had some sharp bends. I've ordered the correct plug to fit it
The motor has rubber mounts so I was thinking I'd make up a bracket and mount it on the bulkhead beside the servo but I'll have another think about it. Probably I'll go ahead and do it that way as the Leaf motor will be way below where I want to mount it. Remember this is still a test mule so if it is too noisy then I'll sort it out on the road car. ;)
 
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Jayridium said:
Nice system Ali, but FWIW, because pressure, and thus vacuum, is "omnipresent", you can put the vacuum sensor anywhere between the one way valve and the servo (the part of the master cylinger that you couldnae mind the name of) - making it easier to "package" up, which will hopefully make your life easier in the installation?
Click to expand...
You say it's omnipresent but the I've heard others having to move the sensor as they had rigged it up in the wrong position. Trouble is I can't remember where it should be, or more importantly shouldn't be. :confused:
 
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Ho with nodges idea, put the sensor in so its measuring the intensity of the vacuum at the point of use. I don't think it will make much difference to what reading the sensor generates, but according to nodge the OE audi pipework is better suited to this arrangement.
 
Just watched Vintage Voltage on Quest.
MG Midget to electric conversion with 5 speed box and a front and rear battery box.

Might be worth a look if you can get Quest. Freeview TV.
They showed in great detail how to make a leaf spring to take the weight but not where they put the batteries!!
Joining motor to gearbox was quite well covered though.
 
andyfreelandy said:
Just watched Vintage Voltage on Quest.
MG Midget to electric conversion with 5 speed box and a front and rear battery box.

Might be worth a look if you can get Quest. Freeview TV.
They showed in great detail how to make a leaf spring to take the weight but not where they put the batteries!!
Joining motor to gearbox was quite well covered though.
Click to expand...
Would you believe I was watching the same show as you typed this message. :eek:
I love Vintage Voltage as we get way more technical detail than most similar shows.
 
Yes I can see the problem!!
Can't you fit one and drive slowly?!?! :D
The project Porsche that they did the other night they did part and owner finished it off.
Must say, it is in a different league to me. They spend £8.5k on a paint job. I was miffed spending £100 on cellulose for my mini!
 
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