Ninehigh
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| posted on 5/5/09 at 01:06 AM |
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Going green
Just spotted that tesla are making a family car now linky and it revived an old idea.
Now I'm not sure what kind of electric motor power you'd need to get decent speeds but I was thinking it would be possible to just slap an
electric motor on the engine side of the gearbox in some way or the other.
Any idea what kind of motor would be powerful enough? Fitting 2 or maybe even 3 (size allowing!) would be an option
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niceperson709
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| posted on 5/5/09 at 03:22 AM |
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There have been several Sevens built with electric power they can have quite good performance but their range is usually woeful!
Most builders dispense with any kind of gearbox because of the massive torque available from the electric motor.
The expensive part is getting good batteries and the right electronics to control the motor but I have heard of people buying battery packs out of
crashed Priius hybrids.
Best wishes IAIN
life is not the rehearsal , it's the show so don't sit there thinking about it DO IT NOW
http://iainseven.wordpress.com/
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Ninehigh
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| posted on 5/5/09 at 03:26 AM |
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quote:
Originally posted by niceperson709
There have been several Sevens built with electric power they can have quite good performance but their range is usually woeful!
Most builders dispense with any kind of gearbox because of the massive torque available from the electric motor.
The expensive part is getting good batteries and the right electronics to control the motor but I have heard of people buying battery packs out of
crashed Priius hybrids.
I've been thinking of that too recently.
Maybe a small petrol engine (say 50 or 125cc) that would be used purely to run alternators to charge the batteries.
As for controls would a variable resistor work? I'm thinking the same kind of system used in Scalextric controllers.
Written off hybrids? I like that idea 
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niceperson709
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| posted on 5/5/09 at 04:01 AM |
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My understanding is that a variable resister is a very bad way to control large motors drawing big currents so you need more sophisticated
controllers.
Your idea about using a small petrol engine to charge batteries has some merit but and this is a big but You would need something bigger than you
suggest to charge the traction batteries.
Why do you think that a Prius has a 1,5 litre engine?
If you are serious a better route might be to get written off Prius and fit its entire drive train into an "atomesque"chassis
Best wishes IAIN
life is not the rehearsal , it's the show so don't sit there thinking about it DO IT NOW
http://iainseven.wordpress.com/
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bilbo
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| posted on 5/5/09 at 06:41 AM |
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There's a very usefull site here which goes into detail about motor, battries, controllers and
everything really.
It's a US site, though, so some of the stuff may not be available here.
There is also a UK based company here who sell a lot of the stuff - never bought anything from them, though,
so not sure what they are like?
---------------------------------------
Build Diary: http://bills-locost.blogspot.com/
Web Site: http://locost.atspace.com
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Mr Whippy
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| posted on 5/5/09 at 07:20 AM |
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looked into this subject myself, all boils down to massive cost to get it going and would take ages to pay for itself (if it ever does), battery
replacement every few years also has to be added on top too. Lithium batteries although very good cost an incredible amount even for a small car so
most folk are stuck with the old heavy lead batteries which haven’t improved much at all. Most electric cars have lame ranges still.
I use a small motor bike to really save money, can't really complain with 110mpg...
Fame is when your old car is plastered all over the internet
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02GF74
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| posted on 5/5/09 at 07:22 AM |
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quote:
Originally posted by Ninehigh
I've been thinking of that too recently.
Maybe a small petrol engine (say 50 or 125cc) that would be used purely to run alternators to charge the batteries.
As for controls would a variable resistor work? I'm thinking the same kind of system used in Scalextric controllers.
A petrol engine to charge the batteries? 
How about this for an idea. To avoid the energy losses from converting heat (petrol engine) to electricity, how about dirving the car from thye
petrol engine. Now there's a novel idea. IF you can get tit to work, trhen I reckon you're onto a winner.
.... but seriously, no. That is self-defeating.
The petrol engine is hybrids is to give more oompf or as a back up when the batteries run flat.
To recoup energy you would whant regenerative braking i.e. have the brakes trun the generator to charge the bartteries.
And as for a resistor, yes that would work but would be verey wasteful as without dpoing the sums, you would need to dissapate kilowatts of heat. It
would need to be pretty big plus you need to have means of getting the heat out.
Electronic switching devices, whilst still wasteful, would be several orders of magnitude better.
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A1
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| posted on 5/5/09 at 07:36 AM |
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priuses arent really that good though...fair enough its hybrid, but you can get the same mpg from golfs.
and the batterys created huge amounts of acid rain in north america where they destroyed large areas of forest to get the metals.
so apart from that hybrid smugness, you dont gain much.
and for these plug in cars its rediculous, cause the power in the socket has to be made somewhere too...usually a big coal fired power station...and
when theres already too much demand on the national grid...
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Mr Whippy
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| posted on 5/5/09 at 07:42 AM |
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iif you look at trains they often use a engine (diesel or gas turbine) to directly turn an alternator which feeds through switch gear to the electric
motors in the wheel bogies.
I thought this might have some merit in a car as not only could the engine be used at a constant optimal speed for efficiency but due to the electric
motors torque, the whole drive train – clutch, gearbox, diff etc can be ditched and replaced with just the electric cables. 4 wheel drive becomes very
easy as does traction control if each wheel has its own motor.
Fame is when your old car is plastered all over the internet
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whitestu
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| posted on 5/5/09 at 07:50 AM |
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The battery on a Prius doesn't have that much capacity [I've got one], so wouldn't power a car without a petrol engine for many
miles.
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MikeRJ
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| posted on 5/5/09 at 07:51 AM |
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quote:
Originally posted by Mr Whippy
iif you look at trains they often use a engine (diesel or gas turbine) to directly turn an alternator which feeds through switch gear to the electric
motors in the wheel bogies.
There are a very good reasons for this though!
a) Motors have maximum torque at zero RPM, just what you need to get many hundred tonnes moving.
b) More efficient than e.g. a torque converter.
c) Much easier to bolt a motor onto a bogey and run electric cables rather then distributing engine torque directly with lots of driveshafts and
UJ's.
A similar system has been proposed many time for cars, using pancake shaped hub motors within the wheels. Unsprung weight is a problem!
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Mr Whippy
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| posted on 5/5/09 at 07:58 AM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by Mr Whippy
iif you look at trains they often use a engine (diesel or gas turbine) to directly turn an alternator which feeds through switch gear to the electric
motors in the wheel bogies.
There are a very good reasons for this though!
a) Motors have maximum torque at zero RPM, just what you need to get many hundred tonnes moving.
b) More efficient than e.g. a torque converter.
c) Much easier to bolt a motor onto a bogey and run electric cables rather then distributing engine torque directly with lots of driveshafts and
UJ's.
but surely these are all also good things in a car too?
Fame is when your old car is plastered all over the internet
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coozer
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| posted on 5/5/09 at 08:09 AM |
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Why don't they take the regenerative braking a bit further and have generators constantly driven from unpowered wheels?
Small 125cc 4 stroke air cooled bike engine turns an alternator at constant rpm, front wheels generating more, rear wheels driven by the motor.
Most of us are not goign to be able to use them motors that oems use. The ones I've seen in hybrids are coils round the flywheel which becomes
the stator.
1972 V8 Jago
1980 Z750
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Mr Whippy
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| posted on 5/5/09 at 08:20 AM |
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quote:
Originally posted by coozer
Why don't they take the regenerative braking a bit further and have generators constantly driven from unpowered wheels?
Small 125cc 4 stroke air cooled bike engine turns an alternator at constant rpm, front wheels generating more, rear wheels driven by the motor.
Most of us are not goign to be able to use them motors that oems use. The ones I've seen in hybrids are coils round the flywheel which becomes
the stator.
Most motors can work as both motor or generator.
My other bike has a ‘Small 125cc 4 stroke air cooled bike engine’, it’s hardly inspirational and not really up to moving any car unless it was made of
papier-mâché and fitted with pram wheels.
All the systems I've looked at need thousands spent to get the parts, even looked at an electric solar car which is very simple but the panels
are still too expensive to be viable
[Edited on 5/5/09 by Mr Whippy]
Fame is when your old car is plastered all over the internet
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02GF74
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| posted on 5/5/09 at 10:33 AM |
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quote:
Originally posted by Mr Whippy
iif you look at trains they often use a engine (diesel or gas turbine) to directly turn an alternator which feeds through switch gear to the electric
motors in the wheel bogies.
yep, that is what I've rread too .... but the torque required to move 5 carraiges loaded up with peeps is a bit different to that to move a 7
type car - it is done to make use of electric motor torque at low rpm.
I doubt it is a good solution for a car.
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deezee
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| posted on 5/5/09 at 01:22 PM |
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Ultimately, with out trying to sound bah humbug  , your going to create a dog of a car, that weighs loads, uses a shocking amount of environmentally
harmful heavy metals, is a pig to drive and has 75% of its "Green" energy produced by fossil fuel power stations.
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Mr Whippy
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| posted on 5/5/09 at 01:59 PM |
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quote:
Originally posted by deezee
Ultimately, with out trying to sound bah humbug , your going to create a dog of a car, that weighs loads, uses a shocking amount of environmentally
harmful heavy metals, is a pig to drive and has 75% of its "Green" energy produced by fossil fuel power stations.
Your totally correct tbh, especially about the heavy metals. At least CO2 gets absorbed harmlessly by plants, oceans etc doubt you can say the same
about Lithium
Fame is when your old car is plastered all over the internet
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Ninehigh
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| posted on 5/5/09 at 06:04 PM |
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Well my point was the petrol engine did nothing to actually drive the wheels therefore you wouldn't need one as big as in the Prius
My mum's got one and on a week in wales you get better mpg in a diesel mondeo 
Surely lithium batteries would be designed to last a good 10 years though?
Another recent thought was one of those gas turbines, but then again that might be even worse.
We could always press Honda to put the fr-v into real production and stop pandering to Calafornia
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