Electric Kit Cars

Electric Kit Cars

Author
Discussion

Olivero

Original Poster:

2,152 posts

209 months

Tuesday 29th May 2012
quotequote all
How many electric kit cars are there on the market at the moment?

I am thinking of cars that are more sporty rather than milk floats...


I would love a 7-clone or to be able to retro fit an Austin Sprite.
Don't need a long range but would like something 'quick'.

Wanchaiwarrior

364 posts

214 months

Wednesday 30th May 2012
quotequote all
here you go, here's one in Western Australia.

http://www.birkin.com.au/electric-birkin-s3-for-sale.php

ajprice

27,446 posts

196 months

Wednesday 30th May 2012
quotequote all
EV conversions have been done a few times on Porsche 914s in America, not a kit car but the ways that some things are done might be transferable to something like a GTM. Google will come up with a good load of stuff to look at.

Edit: you're in America, I didn't mean the American brand of GTM sportscars, I meant the small UK cars based on the Austin/Rover Mini and Metro.

Edited by ajprice on Wednesday 30th May 22:46

FlossyThePig

4,083 posts

243 months

Wednesday 30th May 2012
quotequote all
I'm sure Qdos will be along soon as he has experience of these things.

Midas Cars had a car with an electric motor in it a couple of years ago. I don't know whether they completed it.

Stuart Mills

1,208 posts

206 months

Wednesday 30th May 2012
quotequote all

Anything is possible, but you will need to spend a fortune on batteries unless you have a very light, low rolling resistance, aerodynamic car. The Missile has 18x12v of sealed lead acid and a 11kw 3 phase brushless 216v motor, it runs up to 60mph very quickly but that's the top speed. Gear it for higher speeds and the batteries sink quickly. I am using Lithium in my next EV. I have already spent £3500 on it though for a pack that will run a light car for 100 miles. The Missile did about 40 miles per charge when the batteries were new. More EV info here;
www.vehicle-designer.co.uk see R2, Go-Kart, Quad bike, E-trike and Missile.
Before any shouts "advertising" non of the vehicles listed are for sale.

KDIcarmad

703 posts

151 months

Wednesday 30th May 2012
quotequote all
I believe electric kit car will never work with the current batteries. If you look beyond these and just think about electric motors they offer a lot. Very fast 0 to 60 times, low weight and low down pull. Battery cars are the problem, they are bothy heavy and costly (mostly because of the batteries, which need to be replaced every few years).

Until we get hydrogen to replace the batteries, I do not believe there is a large market for electric kit cars. There is a role for an electric drive car with a ICE (internal combustion engine) generating the electricity. A few years back Fazer Nash had a concept car that use a 800cc engine in a supercar to reach 140 mph! Think of the effect this would have in racing.

Personal I believe this is an area that the kit industry should move into.

Next year a Spanish micro car with electric motors in it's wheels goes on sell. Thing how these wheels could be used.

qdos

825 posts

210 months

Wednesday 30th May 2012
quotequote all
As the OP is listed as being in the USA I was keeping out of this thread but yes there are people building electric kits and in fact any kit could be run on electric power. As for the Hydrogen.... Well sorry but Hydrogen is a complete red herring.

seansverige

719 posts

182 months

Thursday 31st May 2012
quotequote all
Stuart Mills said:
O/T (unless it's being converted to leccy too smile ) but is that an A-M Lagonda in the background?? What's the story there?

Stuart Mills

1,208 posts

206 months

Thursday 31st May 2012
quotequote all
I used to smoke the "wedge" around, I loved it but at 8 mpg she just had to go.
Funny picture now you mention it. My carbon footprint is almost balanced with those 2 cars

Olivero

Original Poster:

2,152 posts

209 months

Thursday 31st May 2012
quotequote all
Yes I am very much based in the US. At some point I am planning to move from NYC to the west coast (LA or San Francisco) where something fun would work.

My feeling is that electric could make sense in a small, light and simple sports car.

Ignoring any arguments for or against electric vs petrol, and what the future might bring battery wise.

The UK makes some great cars and its auto engineering is first class.
The US is great at marketing and the business of business.


Germany seems to be on the right track with cars like the Wiesmann. I am sure there is room for a modern Lotus, Caterham, Cobra car. A blend of all the best bits and ethos, just at a sensible price. But make it modern, light and simple. Not retro and not at a crazy price.







anonymous-user

54 months

Thursday 31st May 2012
quotequote all
Olivero said:
Yes I am very much based in the US. At some point I am planning to move from NYC to the west coast (LA or San Francisco) where something fun would work.

My feeling is that electric could make sense in a small, light and simple sports car.

Ignoring any arguments for or against electric vs petrol, and what the future might bring battery wise.

The UK makes some great cars and its auto engineering is first class.
The US is great at marketing and the business of business.


Germany seems to be on the right track with cars like the Wiesmann. I am sure there is room for a modern Lotus, Caterham, Cobra car. A blend of all the best bits and ethos, just at a sensible price. But make it modern, light and simple. Not retro and not at a crazy price.
ELectric kit cars are just not financially viable really. By the time you've stuffed enough batteries into the car it is no longer light, and kit cars tend to have terrible aero drag and poor parastics (rolling friction) so their road load is high. (assuming you use regen, which you should be using) then the absolute mass of the car is less important, but even then the "round trip efficiency" (battery-inverter-motor-KE-motor(as generator)-inverter-battery) will be in the low 50ish percent region.

The real killer is the cost of a sufficiently powerful inverter and battery system. Lets face it, the car pictured above has 11kW, thats 15bhp, even in something that weighs 350kg thats still catastrophically slow, especially if it hasn't got a multi speed gearbox for torque multiplication.

To match say 100kW of a bike engine car that could weight 400kg, will take you something like £12,000 in inverter, motor and battery system, which would buy you a heck of a lot of ICE power instead!

KDIcarmad

703 posts

151 months

Thursday 31st May 2012
quotequote all
Max_Torque said:
ELectric kit cars are just not financially viable really. By the time you've stuffed enough batteries into the car it is no longer light, and kit cars tend to have terrible aero drag and poor parastics (rolling friction) so their road load is high. (assuming you use regen, which you should be using) then the absolute mass of the car is less important, but even then the "round trip efficiency" (battery-inverter-motor-KE-motor(as generator)-inverter-battery) will be in the low 50ish percent region.

The real killer is the cost of a sufficiently powerful inverter and battery system. Lets face it, the car pictured above has 11kW, thats 15bhp, even in something that weighs 350kg thats still catastrophically slow, especially if it hasn't got a multi speed gearbox for torque multiplication.

To match say 100kW of a bike engine car that could weight 400kg, will take you something like £12,000 in inverter, motor and battery system, which would buy you a heck of a lot of ICE power instead!
Read my posting a few back on using a ICE with an electric drive chain. All the points you are about the battery fueled car not electric car.

Stuart Mills

1,208 posts

206 months

Thursday 31st May 2012
quotequote all
The torque available from electric motors tends to be alomost maximum from zero RPM. This can give excellent acceleration provided the gearing is suitable. The one in the video link below runs at 5000rpm which is quite fast for a motor and is possible as there is no brush gear. The car weighs just over 500kgs inc the batteries. The differential is a 6-1 which means the available torque from a 11kw motor is comparable to a 100 bhp ICE. 0-50 is around 4 seconds and feels very fast as we do not normally associate speed with silence. It has an alomost science fiction whoosh to it!
http://www.youtube.com/watch?v=h_Kkps8M-hI&fea...

qdos

825 posts

210 months

Thursday 31st May 2012
quotequote all
Stuart is quite right. It's not about comparing horse power or Watts. It's more to do with torque and by the way you can put a lot more power through an electric motor when you are accelerating than the motor is rated as. This is peak power...

Anyways if folk think electric means slow then you need to take a look at this video which shows very clearly how those of you out there laughing at the idea of electric sports cars couldn't be more wrong... Try driving an EV some time, you could find yourselves getting a surprise.

Watch this video
http://www.youtube.com/watch?v=oVV9azx4OBA

Oh and that's from 6 years ago too. Electric cars are NOT a joke

Mr Sparkle

1,921 posts

170 months

Thursday 31st May 2012
quotequote all
qdos said:
Stuart is quite right. It's not about comparing horse power or Watts. It's more to do with torque and by the way you can put a lot more power through an electric motor when you are accelerating than the motor is rated as. This is peak power...
Can you clarify this, how are electric motors rated? Is it the case that a 11kW motor produces more than 11kW peak power?

Edited by Mr Sparkle on Friday 1st June 00:36

qdos

825 posts

210 months

Friday 1st June 2012
quotequote all
Comparing electric motors with petrol/gasoline engines is like comparing apples and oranges. Petrol/gasoline engines are rated at their peak power. Electric motors are rated at their continuous power. They're rated at their maximum efficiency, which is designated "continuous", although they are capable of short bursts of power 2-4 times greater than their continuous rating (without damaging the motor), called "peak".

Those of you interested in performance cars will know that it's not just the power you get out of your engine though that matters as such, it's more about where you find it in the rev range and more importantly the power curve, ie how that power is distributed across the rev range. A good example here might be the Mitusbishi EVO and a recent Top Gear video showing off how fantastic it is at out gunning super cars but then they also show it in more normal road conditions being blown away by a Fiat Stylo Estate (see here http://youtu.be/VVt1IjIdLxY?t=8s )

So that's a very breif simple explanation/insight into power but as mentioned above, power isn't really what it's about. There's far more to do with torque which is why diesel cars and Vs are so good. But of course if you want to look at the king of torque you need to look at an electric motor. A quick example we've all probably done ourselves is to try and hold a battery opperated cordless drill/screwdriver stationary and then turned it on. And that's with a measly few watts not kilowatts....

Of course it's an awful lot more complex than this in reality so you can take a look at this page which is pretty good to get a further insight into torque and power, but suffice to say... Don't think an electric motor with only a few horse power is a whimp. You'll be wrong.

http://www.car-videos.net/articles/horsepower_torq...

One last thing to consider is this... What is it that you use to start your engine with? No matter even if it's a V16 1001bhp Bugatti you'll find that it's a small electric motor that gets the thing started.

Stuart Mills

1,208 posts

206 months

Friday 1st June 2012
quotequote all
It is a good idea to remember that;
ICE need to REV up before the car moves.
EV's REV up as the car moves.
My current project involves a 10 kw brushless motor rated at 30 kw peak and 90 Nm of torque. Torque will be 360 Nm at the wheel due to the 4-1 ratio and is available from 0-5000 rpm.
Below is a link to the 11kw MEV overtaking on a dual carrigeway. This runs on Lead Acid batteries. The kit was £4k and the batteries/controller/charger/motor/gearbox cost 3k. The motor was $450
http://www.youtube.com/watch?v=d881zk8t2_E
Mr Sparkle said:
Can you clarify this, how are electric motors rated? Is it the case that a 11kW motor produces more than 11kW peak power?

Edited by Mr Sparkle on Friday 1st June 00:36

Mr2Mike

20,143 posts

255 months

Friday 1st June 2012
quotequote all
It's also a good idea to remember that with an electric motor torque peaks at low or zero speed, and falls off as the motor approaches it's maximum speed. A good ICE will deliver a nearly constant level of torque throughout a wide range of RPM.

anonymous-user

54 months

Friday 1st June 2012
quotequote all
Once again that old "electric motors make peak torque at zero speed so don't need a gearbox" rears it's ugly head. Do the Math and prove for yourself why it's b*ll*cks !!

(and also "practical" electric traction systems cannot make peak torque at zero speed for many reasons)


Finally, try to buy a powerful inverter for little money and see how far you get.



All the points i raised in my post ^^^^ still stand unfortunately.



anonymous-user

54 months

Friday 1st June 2012
quotequote all
Stuart Mills said:
My current project involves a 10 kw brushless motor rated at 30 kw peak and 90 Nm of torque. Torque will be 360 Nm at the wheel due to the 4-1 ratio and is available from 0-5000 rpm.
er, 360Nm at the drive wheels? that's not really a lot of use to anyone is it. My not very powerful family car has 5019Nm at the drive wheels in 1st...........


As i said, cars need gearboxes, no matter if you use an electric motor or an ICE one ;-)