# AC motor car without batteries



## Ziggythewiz (May 16, 2010)

missy said:


> i was thinking to cut the cost down why there is no cars that runs on AC motor and use AC power generator without batteries, shoul be light and cheap to make.
> 1- AC motors are dirt cheap
> 2- 7kw brand new generator are cheap and can be used to drive on 80km
> 
> the setup should be ideal for people who has an old car with stuffed engine.


Quite the opposite. Hybrids are able to use smaller engines because they only need to put out the average amount of power used, with batteries buffering the load. Without batteries, your engine must put out the MAX power necessary, and will run inefficiently the rest of the time.

7kw ~= 9 HP. Hope you don't plan to leave the sidewalk with that much power as your max.


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## frodus (Apr 12, 2008)

Most of them are single phase as well, not three phase.

Single phase motors have very little starting torque, useless in an EV.


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## gor (Nov 25, 2009)

missy said:


> i was thinking to cut the cost down why there is no cars that runs on AC motor and use AC power generator without batteries, shoul be light and cheap to make.
> 1- AC motors are dirt cheap
> 2- 7kw brand new generator are cheap and can be used to drive on 80km
> 
> the setup should be ideal for people who has an old car with stuffed engine.


sure, you can build it, but: 
- 7kw for 80 seems too low - it takes about 17 to maintain 100 km\h, and much-much more to accelerate to this speed 
- 7kw ac motor -cheap? if so, it's very heavy, and need very expensive controller to run 
- 7kw is not a little and cheep genset too
not even considering loses from engine-generator-controller-motor- transmission-wheel, etc, now you need 3 of 7kw motors (ice, gen, motor) to have output of 1 7kw motor. To cut cost down you can throw all this extra weight with losses away and leave only engine and transmission ... or to have only el. motor and batteries 

p.s. to build a hybrid (say ChevyVolt) - it's a very difficult task, even for big OEM with big budgets
unfortunately for people who has an old car with stuffed engine, best option on the budget now - is to get new engine or another car ... unfortunately
people who build electric cars doing it despite it's not their best option financially


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## GizmoEV (Nov 28, 2009)

missy said:


> 2- 7kw brand new generator are cheap and can be used to drive on 80km


The small, one passenger, 3-wheeled car you see as my avatar takes about 8.5kW to hold 80km/h.


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## gor (Nov 25, 2009)

or by AC you mean dirt cheap AirCon?
I gues you can ... that would be a good idea ...


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## missy (Dec 30, 2011)

what I am trying to say, if i fit this motor
http://www.ebay.com/itm/McMillan-4-75kW-6-3HP-Generator-Motor-Capacitor-120VAC-/170752149424?pt=LH_DefaultDomain_0&hash=item27c19f07b0
and attach it to 7KW generator or make a generator by coupling a motorcycle engine to 7HP generator and create cheap hybrid car..


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## frodus (Apr 12, 2008)

frodus said:


> Single phase motors have very little starting torque, useless in an EV.


plus, that motor is too small for a car.


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## EVfun (Mar 14, 2010)

missy said:


> what I am trying to say, if i fit this motor
> http://www.ebay.com/itm/McMillan-4-75kW-6-3HP-Generator-Motor-Capacitor-120VAC-/170752149424?pt=LH_DefaultDomain_0&hash=item27c19f07b0
> and attach it to 7KW generator or make a generator by coupling a motorcycle engine to 7HP generator and create cheap hybrid car..


You would be better off taking the generator engine off the generator and using it to replace the existing gas engine. Converting the generator engine's output to electricity and then back to shaft horsepower is going to get you slightly less power because each of the conversion steps is less than 100% efficient.


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## bjfreeman (Dec 7, 2011)

missy said:


> i was thinking to cut the cost down why there is no cars that runs on AC motor and use AC power generator without batteries, shoul be light and cheap to make.
> 1- AC motors are dirt cheap
> 2- 7kw brand new generator are cheap and can be used to drive on 80km
> 
> the setup should be ideal for people who has an old car with stuffed engine.


Most cars (4,000 lbs with driver) need about 96KW hooked to an transmission. Even if you hook another 3phase 96KW to the engine and connected directly, you have losses in both so you actually have less power.
the Best effenciency is about 80-90%
This only works for 3phase motor/generator.
Then you have the cost of the motors. they are about 2,000 to 4,000.
Finally, in cars is there is no room to hook a motor to the engine then one to transmission.
if you install the Allison hybrid transmission is the best you can do. it uses a battery pack and is about the cost of most cars.


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## mizlplix (May 1, 2011)

What everyone is trying to say is that this is not do able. Your motor is too small. Your generator is too small. 

PLUS: When ever you change energy from one form to another {like gas generator/electricity/electric motor} it loses a percentage of energy due to heat or frictional causes. 

Put togather= small motor/small generator/inefficient power flow= barely able to move at 5 MPH or so.

EXAMPLE: My car.....

2500 Lbs
67 HP motor
2 gears
130 AH batteries @ 120 volts DC

result= it will keep up with traffic.

There really isn't any free lunch. You need to scale up your design to work with todays size cars.

This is kinda confusing at first, but keep reading and you will eventually come to understand better.

Miz


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## charliehorse55 (Sep 23, 2011)

If you do want to get a plug-in hybrid working, this is what you will need:

-At least 20 kWh battery pack, preferably 30kWh of CALB high discharge cells. 
-At least 50kW motor, preferably more
-30kW gasoline genset by Mahle - http://www.mahle.com/C125705E004FDAF9/vwContentByKey/W28LJFHF256STULEN

That's the only genset I know of that's light/powerful enough to work for an EV. It weighs 70kg including the motor/generator.


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## gor (Nov 25, 2009)

charliehorse55 said:


> If you do want to get a plug-in hybrid working, this is what you will need:
> 
> -At least 20 kWh battery pack, preferably 30kWh of CALB high discharge cells.
> -At least 50kW motor, preferably more
> ...


even 20kw 70kg genset - not bad
is it only on paper or only for big OM -not for public? what the price?


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## charliehorse55 (Sep 23, 2011)

gor said:


> even 20kw 70kg genset - not bad
> is it only on paper or only for big OM -not for public? what the price?


No idea, although Mahle partnered with EVO-Electric to make the genset, and EVO-Electric DOES sell to individuals, so their is hope.


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