Help with electric car conversion!

[Isad]

So i am trying to build a electric car
from a Fiat uno and i am thinking of buying 3x36v 1kw
motor out of ebay since thats all i can afforde cuz its
free shipping.Would that be enought to move the car?

[LeChatNoir]

Well depending on the model of Fiat Uni the stock engine is in the range of 33kW to 87kW.
I have no experience in this but I dought anything below 15-25kW would be suitable.

Don't forget $10,000 - $30,000 (if brand new) of batteries to power it and that added weight, could be less or more depending on what you are trying to do.

[Isad]

Well depending on the model of Fiat Uni the stock engine is in the range of 33kW to 87kW.
I have no experience in this but I dought anything below 15-25kW would be suitable.

Don't forget $10,000 - $30,000 (if brand new) of batteries to power it and that added weight, could be less or more depending on what you are trying to do.

I am gettin one for about 150$ deppend either diesel or petrol.And as for batteris i can get 2pc for 50$ used and they go  good for 5 years more then enought i just want to mnow would they be enought to get it moving of curse with the transmision.

[rob77]

the petrol engine has it maximum power at high RPM, at low RPM the petrol engine really sucks - and exactly on those low RPMs is the engine used. 50kW @ 5000rom engine might easilly be a 5kW @ 1500rpm
it's common to use a electric motor with power rating which is only a fraction of the original petrol engine. but 1kW is not enough for a small car - i would go for something in the 4-10kW range for such a small car as UNO.

[Isad]

the petrol engine has it maximum power at high RPM, at low RPM the petrol engine really sucks - and exactly on those low RPMs is the engine used. 50kW @ 5000rom engine might easilly be a 5kW @ 1500rpm
it's common to use a electric motor with power rating which is only a fraction of the original petrol engine. but 1kW is not enough for a small car - i would go for something in the 4-10kW range for such a small car as UNO.

I said 3 1kw or maybe 4 depends since i cant soruce any big motor .but i dont want to go more then 30km/h

[eneuro]

Would that be enought to move the car?

What are your speed and acceleration requirements and expected total mass?
Some kind of optimisation needed to find best solution.
Fiat Uno has not great aerodynamics, so remebrer that power needed to keep  speed 70km/h will be close to ~3 x times (2.7x) higher than driving at 50km/h, while this power is propotional to ~V^3 (speed to the power of three)

From time to time testing classic car driving @ 50km/h at outside city trips while preparing for longer electric vehicle journey and what can I say-it is difficult, while at narrow streets without highways between small cities there are often many trucks which ignore of course those 60km/h speed limits and worse they sometimes try to make signals that you should drive faster, so driving at those economic speeds (I mean low RPM low power diesel engine) is a challenge, but it is doable with additional equipment like additional banners on the car and monitoring system installed at front at back to show donks which try to press you to go faster while you do not have to because of it is not highway with 100km/h minimum speed, but local road with ~50km/h limit 

Conclusion is-it is possible to drive at 50km/h at my local area, so power requirements for electic vehicle can be reduced-how much it will depend on EV aerodynamics and weather conditions, while winter days can be a challenge and difficult roads with snow-additional power needed, worse bettry working condition (preheting and temperature control mich be helpfull), etc...

There are many factors which will affect EV needed power requirements, so without detailed driving requirements it is only guessing what you meant-how much power I need. My answer is it depends for reasons above 

i dont want to go more then 30km/h

Ups, so this will be rather electric bicycle not EV and difficult to explaint other cars members on the road such low speed unless you add at back safety triangle meaning car failure or damage and emergency driving 

[Isad]

Would that be enought to move the car?

What are your speed and acceleration requirements and expected total mass?
Some kind of optimisation needed to find best solution.
Fiat Uno has not great aerodynamics, so remebrer that power needed to keep  speed 70km/h will be close to ~3 x times (2.7x) higher than driving at 50km/h, while this power is propotional to ~V^3 (speed to the power of three)

From time to time testing classic car driving @ 50km/h at outside city trips while preparing for longer electric vehicle journey and what can I say-it is difficult, while at narrow streets without highways between small cities there are often many trucks which ignore of course those 60km/h speed limits and worse they sometimes try to make signals that you should drive faster, so driving at those economic speeds (I mean low RPM low power diesel engine) is a challenge, but it is doable with additional equipment like additional banners on the car and monitoring system installed at front at back to show donks which try to press you to go faster while you do not have to because of it is not highway with 100km/h minimum speed, but local road with ~50km/h limit 

Conclusion is-it is possible to drive at 50km/h at my local area, so power requirements for electic vehicle can be reduced-how much it will depend on EV aerodynamics and weather conditions, while winter days can be a challenge and difficult roads with snow-additional power needed, worse bettry working condition (preheting and temperature control mich be helpfull), etc...

There are many factors which will affect EV needed power requirements, so without detailed driving requirements it is only guessing what you meant-how much power I need. My answer is it depends for reasons above 

i dont want to go more then 30km/h

Ups, so this will be rather electric bicycle not EV and difficult to explaint other cars members on the road that wpeed unless you and at back safety triangle meaning car failure 

Ok so those are good questionquestion.
I dont intend to use that thing for anything else then
city driving and my city is justa huge as field with no road that require brutal force so mainly its gona be city driven or max its gona go to the lake wich is like 20 min away from the city so yeah i dont intend to use it for a lot max its gona do is drive my father to his job wich is like 10 min away and maybe the max speed i would like would be 70km/h but thats never gona happen .Total mass maybe 2 people 3 max so total would go to 900kg.

[mtdoc]

Would that be enought to move the car?

Sure, as long as you're going downhill, .... And with a tailwind..

Seriously though, as others have said, you'll need a bigger motor.

For reference, i have a 1 kW motor on my electric bicycle and I just bought a used lawn tractor (ride on top lawn mower) without an engine that i plan to put a 10 kW electric motor in - which is standard for that type of conversion.

[Isad]

Would that be enought to move the car?

Sure, as long as you're going downhill, .... And with a tailwind..

Seriously though, as others have said, you'll need a bigger motor.

For reference, i have a 1 kW motor on my electric bicycle and I just bought a used lawn tractor (ride on top lawn mower) without an engine that i plan to put a 10 kW electric motor in - which is standard for that type of conversion.

I wish i had anything to buy here if u wana get anything seruis
u either pop 500$ or you go home.

[mtdoc]

You might want to see if you can find a used forklift motor.

[SL4P]

Motor(s)
Batteries
ESC
Brakes
Suspension
Insurance

[Isad]

You might want to see if you can find a used forklift motor.

Thats what i was talking 500$ lol cray cray.

[Isad]

Motor(s)
Batteries
ESC
Brakes
Suspension
Insurance

Insurace rip u can register that thing here assomthing that doesnt need any type of paper just a paper that u are abble to drive it.

[DanielS]

If you are only going to put 3kW into an electrical vehicle, your acceleration is going to be worse than a bicycle: you are accelerating over 10X as much mass with about 1/12th as much power.

[Isad]

If you are only going to put 3kW into an electrical vehicle, your acceleration is going to be worse than a bicycle: you are accelerating over 10X as much mass with about 1/12th as much power.

From what i am hearing here it seems like i can forget evrything i cant finde any motor that is cheaper then 200$
on ebay and there is no local dc motor seller the only one is in
a 2h drive and they sell them for crazy amounts of money.
I really thank evryone who tryed to help me but it turns out i just cant build it.Was gona be a nice summer building that well.

[eneuro]

If you are only going to put 3kW into an electrical vehicle, your acceleration is going to be worse than a bicycle:...

Common, if we take acceleration from 0km/h-30km/h only, than assuming 100kg bicycle with atlete riding it (power 250W) we need ~3.5kJ kinetic energy at 30km/h for bike, so looks like ~14s 
When we do the same for 1000kg EV 3kW power available we get...  ~12s, so very close when forget about other factors and assume only kinetic energy changes.

Probably the bigger issue than slow acceleration could be terrain slopes, so for such low power EV at 1000kg mass journey should be carefully designed and tested alse on ecould end its EV trip at the bottom of the hill depending on motors gears used, while slope will require more power than usual flat driving-gravity energy changes and each 1 meter is 1000*9.81*1m~10kJ which is ~1/3 of its kinetic energy ~35kJ at 30km/h 
In comparision fo 50km/h we need 100kJ to achieve such speed, so easy to imagine than in float terrain road if we keep this speed only aerodynamic and friction to overcome, but slopes... is different story and hill are easier to go down hill than reverse 

[Isad]

If you are only going to put 3kW into an electrical vehicle, your acceleration is going to be worse than a bicycle:...

Common, if we take acceleration from 0km/h-30km/h only, than assuming 100kg bicycle with atlete riding it (power 250W) we need ~3.5kJ kinetic energy at 30km/h for bike, so looks like ~14s 
When we do the same for 1000kg EV 3kW power available we get...  ~12s, so very close when forget about other factors and assume only kinetic energy changes.

Probably the bigger issue than slow acceleration could be terrain slopes, so for such low power EV at 1000kg mass journey should be carefully designed and tested alse on ecould end its EV trip at the bottom of the hill depending on motors gears used, while slope will require more power than usual flat driving-gravity energy changes and each 1 meter is 1000*9.81*1m~10kJ which is ~1/3 of its kinetic energy ~35kJ at 30km/h 
In comparision fo 50km/h we need 100kJ to achieve such speed, so easy to imagine than in float terrain road if we keep this speed only aerodynamic and friction to overcome, but slopes... is different story and hill are easier to go down hill than reverse 

And thats why i hate physic lol.
So your saying it can be done for 30km/h.
But for 70km/h its another story how much force would that need.

[calexanian]

General rule of thumb is 1KW per the effect of 1HP gas engine. This is a bit subjective because the difference in how it is applied mechanically and the torque power band of any particular motor, etc etc, but its close enough as a general rule. Your typical golf cart is at a minimum 5KW and most are in the 7KW to 12KW range. How well would you expect a leaf blower (About 1 HP) to move a Fiat? With enough gear reduction a mouse can move a house, but its going to take a while.

[Zero999]

If you are only going to put 3kW into an electrical vehicle, your acceleration is going to be worse than a bicycle:...

Common, if we take acceleration from 0km/h-30km/h only, than assuming 100kg bicycle with atlete riding it (power 250W) we need ~3.5kJ kinetic energy at 30km/h for bike, so looks like ~14s 
When we do the same for 1000kg EV 3kW power available we get...  ~12s, so very close when forget about other factors and assume only kinetic energy changes.

Athletes can output considerably more power than 250W in short bursts. I'm not a trained athlete but I'm reasonably fit and can probably output more than 250W for a short period of time.

[rob77]

If you are only going to put 3kW into an electrical vehicle, your acceleration is going to be worse than a bicycle: you are accelerating over 10X as much mass with about 1/12th as much power.

dont forget - if it's 3kW continuous , then you can easily overload it to 30kW for few seconds - and few seconds is enough for acceleration. - that's the yet another reason why the electric motor is rated at the fraction of the petrol  : 3kW electric which can be heavilly overloaded to even 30kW (short term) and has the maximum torque from 0 RPM (3 phase squirrel cage motor with inverter) vs. the 30kW petrol which yields only 3kW at low RPM and the torque really really sucks at low RPM.

[Isad]

So in short tearms i can forget anything if i dont have at least
a 7kw motor?

[eneuro]

So your saying it can be done for 30km/h.

I didn't said that, while I never saw your roads, but in the case where I've in my area well know trips in the range of 15km away and registered it with GPS than added height information from maps and while I know it is low trafic there, so low speed is not a problem I can optimise EV wehicle to this road, while there is no need for huge battery pack, I know exactly how energy requirements changes each few meters, so assuming constant speed and not to many breaking and accelerations all it is about math to estimate energy needed, makeing a few experimental trips, register data-how much energy was needed, but with understanding why it was lower or higer power consumption-I knoe I do not need Te$la to drive 

dont forget - if it's 3kW continuous , then you can easily overload it to 30kW for few seconds - and few seconds is enough for acceleration.

For a few seconds acceleartion maybe, but traveling througth long hill at quite high slope a few seconds might be not enougth to provide required energy needed to keep going at constant given speed, while gravity energy need will increase too high with rising slope and we will have to slow down 

[DanielS]

Athletes can output considerably more power than 250W in short bursts. I'm not a trained athlete but I'm reasonably fit and can probably output more than 250W for a short period of time.

Same here. There was a pedal-powered dynamo-meter at a science fair a few years ago and I managed to hold about 700W for 10-15 seconds. This was on a horizontal setup, so no "cheating" using gravity assist. I could probably have gone 100-200W higher on a vertical setup with adjustable gear ratios or resistance. At a more cruise-like effort level, I was around 400W.

[rob77]

dont forget - if it's 3kW continuous , then you can easily overload it to 30kW for few seconds - and few seconds is enough for acceleration.

For a few seconds acceleartion maybe, but traveling througth long hill at quite high slope a few seconds might be not enougth to provide required energy needed to keep going at constant given speed, while gravity energy need will increase too high with rising slope and we will have to slow down 

those conversions are for flat-lands only not just because of power, but also because of bateries. it's rare to see a conversion with a battery bigger than 10kW/h (usually less than that) - and that's only enough for a short daily commute on a flatland
i think such a conversion only makes sense for someone living on a remote "flatland" location with his own solar for charging the vehicle.

[Isad]

I am in a flat land there are no hills
and i only gona be using it in the city.