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Learning how to build Lotus Seven replicas...together!
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PostPosted: Sun Oct 24, 2010 11:34 pm 
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Location: cleveland, ohio
ok heres where i started my thoughts.
how cool is an electric car? we're all here to be different and build something unique so how cooler than it get than something that never exsisted in prodution realm(kind of, hear me out first).
So the idea of a performance electric isnt new. many drag racers have made like 6 or 7 second electrics and Telsa has made their elise based and Fisker is making one but all with very limited range. or hybrids and new EV(elctric vehicle) like nissan leaf and chevy volt and the toyota prius have lots of range but no performance.
So how to get the best of both worlds?

here's the idea thus far.
How to get the best of both worlds? combine the best of both worlds :D
make a lightweight(for an EV at least), long distance capable performance electric.
So the lightweight thing is easy-ish. based on my half completed locost and what i've learned making a space tube frame is the esiest thing of the whole idea. maybe it wouldnt be a 7 in the end but for ease build a basic +442 frame and work from there. it would be hard to make a 7 ver 2000lbs, maybe 2500lbs but thats still light for most anything out there.
Electric portion of EV. found what looks good but maybe not locost. its from AC Propulsion. a 200hp 12,000rpm ac motor that is engineered for EV vehicles with an inverter/controller(needed when using ac motor with batteries) and smart charger so ideally just wire batteries and plug in wall. its all self contained and self monitored so no worrying of frying batteries or needed and electronics wizard to get it to work. no price on this though yet :(
Performance thing is easy-ish. 200 hp, 12000rpm in a 2000lb(ideally) package. wont be fastest but better than most miata or toyota locosts. also figure with a 12,000rpm motor add a gear reducer which helps with torque and would bring the output shaft down to normal gas motor rpm and then connect to a normal transmission to get better usage of torque and top speed and acceleration.
Now the biggest question- Long distance capable.
most EVs run maybe 200 miles or have a gas motor to aid in propulsion(why to tricky for me to deal with) or have a gas motor to charge batteries while in motion and AC motor propulsion for car.
at first i thought rig up a small diesel or motorbike engine running a big ass generator/alternator. but that could get complicated and expensive. so then i thought just buy a portable generator and throw it in the 'trunk'. but seems rather crude and dont need it to run all the time or dont want to get out and pull start it every so often.
so then i thought gas golf cart :mrgreen: most dont idle. the shut off when off gas and quick start when back on(some new production gas and hybrids do this now too)
so either mount big alternator to golf cart motor or rig the gold cart start/stop mechinism to portable generator.
which in turn charges batteries when not capable of get to an outlet for hours to charge from a wall outlet. also this helps not needing as many batteries for the same distance capability.

i realize this is idalistic but i think its sound. i need to finish one 7 before starting another but i think this will be next one.

Lets here feed back and more ideas. any other electric motors be good options? other gas motor generator options and ideas? anything to make it lighter ideas?

thanks and later

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86 rx7 as my dd
90 talon as old dd turned into donor for the locost
06 suzuki sv1ks for the kneedragging fix

mitsu 4g63 powered 442e - viewtopic.php?f=35&t=7317&start=0


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PostPosted: Mon Oct 25, 2010 1:28 am 
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Location: Edmonton, Alberta
For one thing, a 200hp motor will be prohibitively expensive, and far more power than you need.

I'm not sure how well a golf cart generator will keep up to the current requirements of a motor even half that size, but the idea is sound anyway (diesel-electric locomotives for instance).


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PostPosted: Mon Oct 25, 2010 11:18 am 
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Location: Waterloo, ON, Canada
I'm going to bet that a self-contained drivetrain from AC Propulsion will set you back to the tune of $20k. That's my guess. And why on earth would you buy their system and then jury rig their motor to a different transmission? Sorry, but that part is simply baffling.

I'd go with the generator instead of a golf cart motor. The generator is designed to operate at a single speed and make power. The golf cart motor is just going to be horrendously inefficient and dirty.

I too would love a Lotus 7 EV, but I abandoned that idea long ago based on cost. The batteries will make or break it, and that's where you'll run into the tens of thousands of dollars. If you *really* want to do this, wait for the Nissan Leaf to come out, wait for one to crash, and then use it as a donor. Seriously. That will be the cheapest way to do it without having to get a doctorate in electrical engineering (or learning via failure).

One thing that you haven't made clear is why electric? Yes, it's "cool", but so would a turbine-powered vehicle, or a compressed air vehicle. Is this a case of "I can do it, so I will" or are you looking to electric for efficiency?

Sorry if I'm raining on your parade, but electric propulsion at a reasonable price is still a long way off.

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Exploring every single option, permutation, and possibility, to figure out what flavour of awesome I want.


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PostPosted: Mon Oct 25, 2010 11:43 am 
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While electric setups are "getting there", they still can't beat a small turbo diesel in an aerodynamic body. Heck, our own Jack here got 70 mpg at 70 mph in a Locost with said diesel.

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PostPosted: Mon Oct 25, 2010 12:00 pm 
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Location: cleveland, ohio
I don't know cost. I was thinking 7k-10k. If its in. The $20k range that which it very well could be, then WOW! Neither is locost but obivously a difference.

As for transmission the AC P setup just had the motor and output shaft. No other trans involved. I'm guessing its usually used like the Tesla without trans.

I kind of figured a generator would be better. Especially if I can rig up the start stop feature to it to coincded with the whole vehicle.

I know good batteries are ridiculous but say 10 deep cycle marine batteries would be about $1000. I know lithium ion are better in every way but for the cost of them.

As for using a production car donor I don't know if it'd be cheaper as I bet wrecked ones go for a lot still. And i'd have to reengineer it into a different package which is just as bad as building from scratch to me.

And why? EVs aren't just some crazy idea anymore than cars as we know them were less than 100 years ago. It might never happen for me as cost is an issue for me too but the more refined the idea of a LocostEV gets and more technology advances(gets cheaper) the easier it will be one for one of us to get the first one done

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86 rx7 as my dd
90 talon as old dd turned into donor for the locost
06 suzuki sv1ks for the kneedragging fix

mitsu 4g63 powered 442e - viewtopic.php?f=35&t=7317&start=0


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PostPosted: Mon Oct 25, 2010 12:07 pm 
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Oh and its not to save the environment. I know that burning fuel to charge batteries negates a portion of that. Then to plug in the house uses electricity which is made by coal burning or nuclear mostly(I think this is right, correct me if wrong).
Then there is battery disposal which is just about as toxic as anything else short of nuclear waste.

Not trying to save the planet. I think a well built large displacement 4 cyl turbo would be best for efficency and performance. Just have some fun in a different way

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86 rx7 as my dd
90 talon as old dd turned into donor for the locost
06 suzuki sv1ks for the kneedragging fix

mitsu 4g63 powered 442e - viewtopic.php?f=35&t=7317&start=0


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PostPosted: Mon Oct 25, 2010 12:32 pm 
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Location: Tecumseh, Ontario Canada
http://www.amazon.com/Build-Your-Own-Electric-Vehicle/dp/0071543732/ref=dp_ob_image_bk

Is a pretty good book on the subject.

It's kind of a moving target hardware wise as there are plenty of folks working on the hardware -- some of the biggies have gone into bankruptcy recently.

The book goes into AC and DC setups and pretty strongly hints that DC is the way to go for DIY folks at this point from a cost and practicality standpoint (apparently there are significant advantages to AC power but the cost of AC speed controllers and variable speed motors is prohibitive). I think they're recommending motors in the 20-30hp range as suitable for most DC vehicles, apparently the maximum torque at zero RPM of an electric motor requires you to rethink horsepower requirements.

Cool idea, very practical for a "city car", 50-100 mile range is quite do-able DIY for ~$10,000. Cheaper if you have some electronics knowledge and are comfortable soldering together your own speed controller and high output charging system.

Cheers, Ted


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PostPosted: Mon Oct 25, 2010 6:19 pm 
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EVs just REALLY aren't there yet. Good batteries= $$$$, regular batteries = poo, all of it is expensive and relatively heavy. Look at the X-prize winners and see what they said about why they solved the problem the way they did. EV's were too heavy and the range was too poor -- they even abandoned the hybrid for the same reason. The winning combo? 250 cc turbocharged motorcycle engine. I think you could probably do 80-100 in an NA ex-250 Kawasaki and a light-weight aerodynamic body, but a Lotus body ain't going to cut it for efficiency (too 'dirty').


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PostPosted: Mon Oct 25, 2010 7:30 pm 
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speaking only as a proof of concept vehicle mind you. ..
what if you used the electric propulsion motor and cvt from a prius without a directly connected gas motor? (i saw a used setup of this for sale the other day) a battery/supercap pairing provides amperage bursts for acceleration and the storage ability to cover some ground while reducing some of the negatives of lead acid batteries(discharge rate/depth of charge issues/weight/etc). a small apu with a capacity of maybe 1/2 of the max drivetrain draw might be able to provide enough of an in flight recharge to give you what you're looking for. average use of course, loud stereos, disco balls, etc don't count :wink:

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For instance, a whole beer bottle isn't half the weapon that half a beer bottle is ..." Randall Garrett


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PostPosted: Mon Oct 25, 2010 8:53 pm 
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Location: Austin, TX
Go to ecomodder.com and read up on EV conversions. Several completed conversions will give you an idea if you want to proceed.

Good luck.


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PostPosted: Mon Oct 25, 2010 9:12 pm 
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Location: Tecumseh, Ontario Canada
kennyrayandersen wrote:
EVs just REALLY aren't there yet.


It's all a matter of perspective. Right now EV people are like hot-rodders and LoCosters, innovative and willing to put up with a few inconveniences to be on the bleeding edge. There's a lot of merit to the argument that our cars aren't very practical or cost efficient, but we build and tinker with stuff for fun and personal gratification.

For a home-builder, high energy density batteries and AC powertrains are economically untenable, but a perfectly serviceable DC Lead/Acid car is viable and practical for use as a low to medium range city or town commuter -- sure it's scaled up golf kart technology, but...

t


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PostPosted: Mon Oct 25, 2010 9:23 pm 
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i want to emphasis the "Performance" part of the subject. i dont care about mileage whatsoever. it needs to perform as well as say the average 7 with a normal internal combustion engine(ICE). in terms of speed and handling/agility. obviously being slower than an ICE 7 and getting worse equivalent mileage wouldnt be acceptable but being faster with worse mileage would be just fine within reason.

and the idea of a long distance to me is being able to stop for 15 mins and be ready for couple hundred miles more same as stopping to fill up in an ICE 7 and getting 200+miles(figure 8 gallon tank and 25+mpg) before another gas stop. its true i commute 10 miles round trip to work so i could drive to work all week on one charge but i otherwise live 25+miles to anywhere with a Walmart or mall or commercial business area so it would start putting that into question.
even if stopping for 15 means parked with just generator running to help keep up a charge on batteries.

_________________
86 rx7 as my dd
90 talon as old dd turned into donor for the locost
06 suzuki sv1ks for the kneedragging fix

mitsu 4g63 powered 442e - viewtopic.php?f=35&t=7317&start=0


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PostPosted: Mon Oct 25, 2010 9:47 pm 
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as for tech. my understand is like ted andkidle said of AC vs. DC. DC is cheaper and instant torque, AC is more efficent and has a powerband.
so AC is better except for price and instant torque would likely shred tires at a rate that would make up the difference in cost of DC motor :mrgreen:

as for batteries Li-ion is better than lead acid except for price. so lead acid works but might suffer from more weight and less output. in my theory the onboard generator would replace a section of batteries but would make up for it by keeping the remaining batteries well charge. thats without doing any math on discharge rate and draw from propulsion motor compared to charging rate of generator. doing that math might mean i need a 500lb industrial generator and a ton of batteries which would throw the whole idea out the window. i doubt the math will be that off but i havent dont the math so if anyone else might have speak up please :idea:

i like it all so far guys so lets keep it up. maybe a nice well funded somebody will stumble upon this and finance the whole operation :cheers:

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86 rx7 as my dd
90 talon as old dd turned into donor for the locost
06 suzuki sv1ks for the kneedragging fix

mitsu 4g63 powered 442e - viewtopic.php?f=35&t=7317&start=0


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PostPosted: Mon Oct 25, 2010 11:08 pm 
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[quote="lusiphur134"]i want to emphasis the "Performance" part of the subject. i dont care about mileage whatsoever. it needs to perform as well as say the average 7 with a normal internal combustion engine(ICE). in terms of speed and handling/agility. obviously being slower than an ICE 7 and getting worse equivalent mileage wouldnt be acceptable but being faster with worse mileage would be just fine within reason.
quote]
80% of rated torque available at launch typically. the accel/deccel cycle on a tight track might create overlarge amp draw/return pulses (assuming regen braking) and batteries aren't good at high amp pulses, another good reason to run "supercaps" on each battery. they have really big ones for transit buses but smaller ones are available and the weight/power tradeoff is pretty impressive. really bulky though......

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"There are times when a broken tool is better than a sound one, or a twisted personality more useful than a whole one.
For instance, a whole beer bottle isn't half the weapon that half a beer bottle is ..." Randall Garrett


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PostPosted: Tue Oct 26, 2010 12:00 am 
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Location: Park Hills, KY
Research on EV's is how I found the LocostUSA forum...

The AC propulsion motor/inverter kit is right about an even $10k... I wouldn't use anything less than LiIon or LiFe batteries with the system, unless you're going to spring for ultracapacitors, which cost just as much and are quadruple as rare... The battery pack required to reach that 200 hp using LiIon costs just a hair over $11k...

However, using a set up like this guy: http://www.plasmaboyracing.com/ is significantly cheaper, and obviously incredibly potent.

Plasmaboy Racing has one of the best performance-based setups I've seen, siamesed Warp 9 DC motors, modified Zilla controller. Check YouTube for the White Zombie electric drag car. In the early stages, he was using dry cell/gel batteries... You could replicate his earlier setup for less than $8k, if I remember the numbers...
For motor info, check out http://www.go-ev.com/


Research the tZero(precursor to the Tesla Roadster). Early versions used drycell/gel batteries and the AC150 system.

There is a 7esque car called Thorr that is completely electric, may use AC bits, not very clear what the drivetrain is made up of... at least wasn't 2 years ago when I was looking...


ProEV is another great company to get in touch with, they are/were campaigning an electric, all-wheel drive Impreza.

I'm not affiliated with any of these groups, just got really pissed off when gas hit $5.00 a gallon...lol!

I'm at work right now, so can't access my folder of EV bits, but I've got plenty more info I could send along if you're interested...


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