[Thomas4200]

I want drive this car by an éléctric motor but now i'm hesitate between a transaxle and a hub motor

For transaxle is difficult to find a gear ratio about i=6, i have find but work with chinese is a little difficult...

see picture of drawing i use for research, if anyone want a drawing or 3d file, tell me

For hub motor(x2 in traction or propulsion), i don't undersand who the controller(x2) simulate the differential, if anyone can explain me what happen with 2 hub motor ?

see product i want to buy : https://fr.aliexpress.com/store/pro...60.html?spm=a2g0w.12010612.0.0.f5477442zCbHQi

Have great day

Tom

 

[Thomas4200]

Bye bye thermic motor

 

[prensel]

According to the license plate I assume you are from France ?

Before converting anything did you check with the registration offices if they ALLOW the conversion and do you have the required EMC paperwork for the approval ? Without either of these just forget about driving this car on public roads.

Why not get one of these allready electric Peugeot 106 or Citroen Saxo, Berlingo or Partner, they are cheap (under 1000 euro) and easily available in France and will save you a lot of trouble getting it registered

 

[Thomas4200]

You have reason, i live in France

i want to make a transformation on this car because this vehicle is in the public domain

This car unloading weight 250 kg and after electric conversion near 350kg

a manufacturer electric car is too heavy for recharge with solar panel or need very big surface

I have a little society in design and programming machine, see this, i have conceive this product : http://www.alicatt.fr/e301.html

In France the laws are brought

I make this car for hobby and for increase my skills in electric mobility

if you want help me for technical problem, i'm happy

and if i can help you, i'm happy too

Have a great day

Tom

 

[prensel]

Hi tom,

You have reason, i live in France

i want to make a transformation on this car because this vehicle is in the public domain

NO it isn't when you replace the combustion engine with an electric motor.
You will loose the cars registration when doing this and you have to apply for a NEW registration.

But if you keep your battery voltage below 60V you PROBABLY dont have to comply to some EMC requirements but still need to apply for some tests.

Better check this first before investing time and money in a nice but unusable project.

 

[Thomas4200]

thank you for your attention, in the background, you're right but I think that in France it is necessary to provoke a little things for which evolve

I know that the vehicle will not have the right to drive on the public road

I have already contacted the probate service but in France you know, everything is complicated

I have previously set up a heavy truck camping, I do not explain the folder to write "camping car" on the papers of the car, then to change the engine is not won

I make this car but i like electric motor, this little car will be run in propriety, not public road

in France, voltage is complicated after 50v so normaly i must use a 48v system

Can you explain the problem with 2 hub motor et 2 controller, what happen because no differential ?

You have see "who killed the electric car " ?

bye

 

[Thomas4200]

Hi,

I have find a video that explain the problem with 2 hub motor

https://www.youtube.com/watch?v=4qf1TkFGSWA

it confirms what I think, it is necessary to cut or slow down an engine according to turns

So i buy product (link in an other post)

and if you want i come to you for explain my solution to drive 2 controllers and 2 hub motor(simulate differential), now i think i had 1 potentiometer (or 2 for security) on steering control and 2 or 4 inductive sensor on support wheel to check problem

Have a happy day

Tom

 

[Duncan]

No you don't need to do any of that
The road will do it for you!

 

[brian_]

I want drive this car by an éléctric motor but now i'm hesitate between a transaxle and a hub motor
...
For hub motor(x2 in traction or propulsion), i don't undersand who the controller(x2) simulate the differential, if anyone can explain me what happen with 2 hub motor ?

see product i want to buy : https://fr.aliexpress.com/store/pro...60.html?spm=a2g0w.12010612.0.0.f5477442zCbHQi

I don't see anything in the description which explains how they handle the speed difference between two motors.

With AC (and BLDC) motors, since the motors are turning at different speeds they each need their own controller/inverter, running at different speeds in turns, and coordinated. Curtis Instruments (a popular supplier of AC controllers) includes this feature; they call it "Dual-Drive". In this system, one controller acts as the master, with the accelerator input connected to it; the other controller is the slave, and is connected to the master by a CAN bus cable. There is a sensor attached to the steering which tells the master how tightly the vehicle is turning (and which way), so that the controller knows how the two wheel speeds should be related.

No you don't need to do any of that
The road will do it for you!

With DC (not brushless "DC") motors, you could just connect them to one controller in parallel, but I'm not sure that you would like the result.

 

[Emyr]

No you don't need to do any of that
The road will do it for you!

Yes, but police officers frown at on-street tyre smoking.

It's possible to calculate an ideal speed differential given a known vehicle track, wheelbase and steering angle. The challenge is working out how to manage torque-oriented throttle with speed limiting for the inside wheel, with added complication to detect and accommodate wheel slip.

 

[Duncan]

Hi Emyr

99% of all cars ever sold have an "Open Differential" - which has ZERO control right to left - the road does it all!

Any of the designs involving two motors have more control right to left than an Open Differential

If the OP was making some sort of high performance machine THEN it could be worthwhile looking at some form of torque control

But he is making a low power machine - there is simply NO NEED for anything at all complex

Don't make things more complex than is needed!

 

[Thomas4200]

hi Brian and Duncan,

Brian :
Video not explain really the problem so show a system, this video just confirm my think

I have been working with Curtis for several years with little DC controller but I did not know the dual drive, I think it's a good option but it requires to buy the controller at Curtis, i have contact Kelly controller for this function but i have no response for now

But i prefer create an independent system, so if i want i change motor or controller, i can choose in all brand

So, i will create a little electronic card for receive potentiometer of accellerator and position of steering control and after a little algorithm i control 2 digital potentiometer for drive 2 controller

Duncan :
my first thought is the same as yours but I prefer to predict the worst, I will try and if it is not necessary, I will not make an electronic card to drive the controllers
Have you an exemple on a forum or web site or video, i can't find on diyelectriccar because i can't find the search barre, if you can help to search in forum it's good, very thanks

Have a great day Boys and Girl

Tom

 

[Duncan]

Tom
as I said EVERY open diff car on the road operates with the road making the wheels go at the right speed

This even applied to the days in my youth when I was interested in Twini Mins

A min with an engine in the front and another in the back - again just the road acting to synchronize them

 

[Karter2]

As Duncan said, you are wasting your effort on totally unecessary complication.
Remember, vendors will be happy to indulge your experimentation since it means more income for them.
I also suspect you are wasting money on those hub motors as well, as the performance will most likely disapoint you.......but that is your choice.!

 

[Thomas4200]

Ok Duncan

So why Curtis have created dual drive, for machines that works like a tank or wheelchairs (for invert motors direction)?

You have not send me link about car with 2 hub motor

I have just one think, I'm in a hurry to try

if you say true, the electric car is childishly simple to manufacture

Have a great day

Tom

 

[Thomas4200]

Hi Karter2,

i will create electronic card if it necessary, if not i don't create this

i'm programmer and designer, it is not problem for me

You think hub motor isnt a good choice, please explain me, do you have experience feedback ?

see you soon

Tom

 

[Karter2]

Hi Thomas,
How many electric cars do you know of using hub motors ?
No commercial EVs, and Very few if any DIY cars.
Several projects have tried to use them, but had disapointing results or failed
Generally, hub motors do not have enough torque for hills, and are difficult to get controllers to work with.
The few that work are expensive.
Your project would be simple, cheap, and effective using modified golf kart components.....either the whole drive package, or just the axle and some other motor/controller system.

 

[Thomas4200]

hi Karter2,

Thanks for your observation it's true

i think hub motor is a very good idea, no gear, no differential, no transmission but the power limit the speed and acceleration, i think this motor have application but not for car like more than 500kg and speed 90km/h

I want to believe in this dream because it's a little slow car

specification of car :
-Max speed :45 km/h
-Max load : 600kg exceptionally otherwise normally 450kg
-Diameter wheel : 460mm

see my calcul if you want

motor torque is 130Nm (i have demand curve to manufacturer)
(on spécification max torque is 180Nm but curve says 130Nm)

if i want go 0 to 45 km/h in 5 seconds, normally i need 1250N (2.5ms2 X 500kg)

2 hub motors can push 1130N ((130Nm X 2) / 0.23m)

my car normally can run 0 to 45 km/h :

- 5.5 s (on flat floor) (1130 = 500 x 2.26) and (12.5/2.26 = 5.5)

- 6s on hill 10% (5.71°) (1130 = 550 x 2.05) (12.5/2.05 = 6)

(I do not consider any friction given the low speed)

You can confirm me this please if you want ?

i think its possible for my application but i'm not drive 90km/h, if i want that i need more powerfull

I have another doubt, is that the motor hubs are not more fragile because of a direct impact with the road ? what do you think ?

see you soon

Tom

 

[brian_]

99% of all cars ever sold have an "Open Differential" - which has ZERO control right to left - the road does it all!

While I agree that the same equal-torque behaviour as an open differential should be fine in this case, the above statement is no longer true. While most (but probably not 99%) of currently available vehicles have open differentials, in North America all current production vehicles are required to have electronic stability control, which includes individual braking of left and right wheels. That ability also provides traction control.