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Electric Atom
Dantheman - 10/6/07 at 01:58 PM

I've been struck with the idea of building an electric powered Atom style car! I have no idea where to begin though really, such as sourcing a suitable motor, batteries etc etc. But I just thought I'd share it with you and see what you think. Does anyone know where I could get more info on building electric cars?

I'm not doing this because I'm worried about my "carbon footprint" or to be all green, I just thought it would be something differant.

Danny.


smart51 - 10/6/07 at 02:32 PM

I've been thinking about an electric car too. There is an electric car builder forum but it almost never gets posts.

There are no good donors to get motors from. The G-Wiz / REVA is only 17.5 BHP. Automotive motors are much lighter than industrial ones but are much rarer. This is partly beacuse industrial motors are sized to run at 1500 or 3000 RPM. Run them at 8000 RPM in a car and the same sized motor makes 3 - 5 times the power for the same weight.

Car motor controllers are also thin on the ground. It would make for an easier SVA though, with no worries about emissions or noise.


Dantheman - 10/6/07 at 02:41 PM

I'm quickly coming to the conclusion that this is not a very practical idea...


CraigJ - 10/6/07 at 02:46 PM

isnt there a video of an electric atom on youtube?


goodall - 10/6/07 at 03:07 PM

a good source of gel type lead acid batteries is "used" batteries from large ups units. they only ever get used for about 2 cycles in there life. can be got for next to nothing since theres no market besides to the battery re-manufacturers.

there might be lighter alternatives to gel type lead acid but theres a certainly the cheapest



iv been thinking of the idea of getting an old awd car, pulling the gearbox out fitting the 2wd version and then power the back axle by a electric motor, ideal for standing traffic and up to about 5 mph, then use the petrol engine for higher speed


nitram38 - 10/6/07 at 03:08 PM

Been done already


Fatgadget - 10/6/07 at 03:13 PM

Loads of info about EVs here


tegwin - 10/6/07 at 04:27 PM

You need a threephase motor and lithium cells.... to get the maximum amount of torque for the least weight

And as for the electronic controller....Its not a particularly complex system...go the locost route and make one


speedyxjs - 10/6/07 at 04:36 PM

If you want to make an electric car, get all the info you can on the electric se7en


StevieB - 10/6/07 at 05:27 PM

There was a Dutch company who built an electric Indy - they featured in a kit mag a year or so ago.

I can't remember the name, but I remember the article stated that MK were in contact and could supply the running gear - I remember because the performance was, well, electric and I thought about building a leccy indy myself.

Bit of a problem for going touring though


kb58 - 10/6/07 at 05:31 PM

tegwin wrote

quote:
And as for the electronic controller....Its not a particularly complex system...go the locost route and make one


I can only guess you specialize in power electronics and/or are joking. It's far from easy to make your own. In fact it can be downright dangerous and burn everything to the ground. You think everyone knows about Rds and shoot-through? Hahahahaha.

[Edited on 6/10/07 by kb58]


smart51 - 10/6/07 at 07:04 PM

quote:
Originally posted by kb58
quote:
And as for the electronic controller....Its not a particularly complex system...go the locost route and make one


I can only guess you specialize in power electronics and/or are joking. It's far from easy to make your own. In fact it can be downright dangerous and burn everything to the ground. You think everyone knows about Rds and shoot-through? Hahahahaha.


I have a degree in electronics engineering and work for a company that makes a 3 phase electric motor controller as part of their electric steering product. I'd be nervous of building my own with a 300 or 400V battery pack. I bet I could do it but I bet I've be scared to put my fingers near it.


Bob C - 10/6/07 at 07:34 PM

I will do the electric kitten in the fullness of time..... It won't be a performance car though!
Motor - am using an idustrial TEFC induction motor, but getting it rewound, to use lower voltage.
Inverters is what I do for a living - so yes I'll be making my own,
It's a BIG job, apart from the drive electronics there are a stack of power converters required - battery charger (with power factor correction), fully isolated. 12V auxiliary converter for all the car stuff (horn, lights, wipers etc).
The motor & inverter will be liquid cooled using the heater matrix & probably diesel as the fluid.
New off the shelf items that the high performance guys are using is ruinously expensive & the PM synchronous motors have interesting safety issues when run in field weakening (high speed). And no way can I afford anything but lead acid caravan batteries!
I'll keep updating my website as and when I do stuff.
Bob


Mal - 10/6/07 at 07:34 PM

I saw the electric MK at a show and it was obvious that a lot of know-how about electronic thyristor motor drive systems and software was used. It was difficult to assess the costs involved, but I doubt it was cheap.
About 5 years ago a Tiger with electric drive featured on the front cover of Which Kit, or the other one.

Mal


RazMan - 10/6/07 at 08:56 PM

Here's an interesting link showing some more info on electric sports cars - the Tesla is my favourite, followed by the Fetish.


smart51 - 10/6/07 at 09:20 PM

quote:
Originally posted by Bob C
The motor & inverter will be liquid cooled using the heater matrix & probably diesel as the fluid.



Hot diesel and high voltage electricity. And some say water and electricity don't mix.


Bob C - 10/6/07 at 10:10 PM

. And some say water and electricity don't mix..

that's why I'm not using water....
seriously there's enough volts to electrolyse water - & I don't plan to install a de-ionising plant!!!!
You can light diesel easily enough if you have a wick. otherwise it's quite hard....
Bob


MikeRJ - 10/6/07 at 10:18 PM

quote:
Originally posted by Bob C
The motor & inverter will be liquid cooled using the heater matrix & probably diesel as the fluid.


Would transformer oil not be more suitable?


Bob C - 11/6/07 at 08:48 AM

Good point Mike - Diesel has 2 advantages, easy, cheap supply & compatibility with seals etc in automotive stuff - once you go more exotic it's hard to get compatibility data/guarantees. But the transformer stuff would undoubtedly be better electrically
Bob