Cambell Live - DIY electric car. Inspired?

[Coyote]

Who else has been inspired into making an electric powered vehicle? I've wanted to make an electric bike for a while after growing up with R/C cars and loving the whine and instant power. Also the videos on youtube of the electric powered drag bike were incredible. Has anyone thought of doing such a project themselves? I'm keen, only I can't even afford to keep my bike running so can't really do anything for a while. Anyone know where you'd get the motor and running gear from?

Was a good article on Cambell Live. Haven't seen the youtube vids yet due to xtra's dial up speed broadband

[JimO]

12k is a lot of money for something that will only cover 60 ks....but good on him anyway

[Swoop]

12K less 2.6Kpa saved on benzine!
$2- per 60km...

[davereid]

12K less 2.6Kpa saved on benzine!
$2- per 60km...

Yeah.. but are those figures really correct ?

Lets take a small jappa car. It would have an engine of about 70-80kw. Maybe we use full power 1% of the time, but an acceptable guess would be that we use about 1/2 of the engines power on average over a normal trip.

So it would be fair to say we need a 80kw engine output to get toyota corolla levels of performance, and we will use about 40kw of energy each hour in our 800kg car.

But our electric car carries 1/2-1 tonne of batteries. So maybe we will need 50-60kw each hour to emulate the performance of the corolla. Or we accept a lower level of performance.

If we are using 50kw/hr of energy, at a rate of $0.20c, our 1 hour of driving will cost $10.

This is comparable to, or more than the small car we were using !
And we will have to budget for battery replacement. We may even be liable for road-user mileage charges, as our fuel is not taxed.

The reality is that a given level of performance will require a certain amount of energy. Regardless of the fuel source.

So when I hear claims that electric vehicles are cheap to run, I am a little skeptical. I am sure they are, but only because they are not being asked to match the performance levels of the vehicles they replace.

[Coyote]

Power companies are already bastards, I'd half expect them to turn into gas companies and change their prices on the fly.

I'll try get hold of a cheap rolling chassis and see what I can do with the little funds I have. The guy on Cambell live spent so much getting other people to do the work by the sounds of things

[Coyote]

But our electric car carries 1/2-1 tonne of batteries. So maybe we will need 50-60kw each hour to emulate the performance of the corolla. Or we accept a lower level of performance.

If we are using 50kw/hr of energy, at a rate of $0.20c, our 1 hour of driving will cost $10.
0.20c per watt? (pardon the pun)

The guy in the article was using it as a typical car and was able to reach highway speeds, so he was needing similar performance to a standard car. They didn't say how they worked out 60km = $2

[Finn]

I'm sure a tonne of used batteries will be good for the environment too. Not to mention the energy required to charge his batteries.

The guy should be shot.

[nodrog]

The guy should be shot.

with a tazer.....

[vifferman]

They didn't say how they worked out 60km = $2
Basically, the batteries needed recharging after 60km, and he reckoned it would cost $2 to charge them. I dunno what the current rate is per kilowatt-hour, but assuming 20c, that's 10 kilowatt-hours (meaning charging up overnight for ten hours using a 1kw charger, or 5 hours using a 2kw charger). The thing is, assuming no losses due to heat etc., that would mean either his car's electric motors are only 10kw, which is unlikely, or he's severely underestimated/understated the cost of charging, which is more likely to be somewhere between $8 and $15. That in itself raises another problem: if his car is actually say 40kw, then it's going to require 20 hours to charge with a 2kw charger, or 10 hours if he's got some super-duper 4kw charger and some special wiring in his house/gargre to power it.

So, we can assume that either his electric car motors don't provide power equivalent to the engine they're replacing, or he's deluded about the cost of running it.

But at least he's saving the baby fursealwhales, preventing globular yawning, and making the Greenies orgasmically happy.

[Pwalo]

I'm sure a tonne of used batteries will be good for the environment too. Not to mention the energy required to charge his batteries.

The guy should be shot.

Yep, that's the down side for all the petrol/electric hybrid cars as well.

They're no more ecologically sound (if there is such a thing), as anything else on the road.

Still I kind of like the idea of a remote controlled R34. (Sorry officer I wasn't behind the wheel?)

[Fooman]

Yeah.. but are those figures really correct ?

So it would be fair to say we need a 80kw engine output to get toyota corolla levels of performance, and we will use about 40kw of energy each hour in our 800kg car.



Checking my trusty Bosch Automotive Handbook, that's a bit high - for a blocky sedan, with a frontal area of 2 square metres (average), the drag power (~80% of the total resistance needed to be overcome by the motor) is 6.3 kW at 80 km/h or 21 kW at 120 km/h.

For a normal car with aerodynamic features, those figures are 4.6 kW at 80 km/h or 16 kW at 120 km/h. For a fully streamlined car (e.g. the solar powered racers), the figures are 2.3 kW and 7.8 kW.

So for a modern toyota corolla, we're looking at between 6 and 20 kW to maintain (legal) open road speeds (drag + frictional resistance in drivetrain).

Of course, more power is needed for acceleration or going up hill (or turning on AC and other ancillaries), but they are short term transients.

Cheers,
FM

[Badjelly]

If we are using 50kw/hr of energy, at a rate of $0.20c, our 1 hour of driving will cost $10.

This is comparable to, or more than the small car we were using !
And we will have to budget for battery replacement. We may even be liable for road-user mileage charges, as our fuel is not taxed.

The reality is that a given level of performance will require a certain amount of energy. Regardless of the fuel source.


Sorry, but I don't trust your figures. I don't think a small car on a "normal trip" has an average power consumption anywhere near 50 KW.

You're right that the energy the electric car is using isn't free. The potential advantage of electricity over petrol is that the in-car efficiency (electricity -> motive power) is high and the generating efficiency can be substantially higher than a mobile engine can achieve (eg > 50% for a combined-cycle gas power station or ~ 30% for a coal-fired power station vs [what?] for a petrol engine). Then there's regenerative braking, though not for our DIY bloke.

I'm not denying there are several disadvantages of electricity in cars, too, mostly to do with those heavy, expensive, not very environmentally friendly batteries.

[Hoon]

I'm sure a tonne of used batteries will be good for the environment too. Not to mention the energy required to charge his batteries.


Not really. He is using 12 car batteries which are recyclable. The footprint left from these will still be way less than years of petrol fumes.

Even if you factor in the pollution caused by the generation of the power to charge the batteries, in comparison energy produced from a power station is still way more efficient (and therefore green) than that produced from a petrol engine.

I saw the Campbell piece last night too and was quite impressed. The article was very vague but instead of making my judgement based on that I took a look at the guys website instead (http://www.kiwiev.com). The motor specs and battery info are all up there. He uses 12 x 3.4amp battery chargers bought from SuperCheapAuto.

He epitomizes the typical kiwi bloke that could acheive anything in his shed if he puts his mind to it.

[Badjelly]

The guy in the article was using it as a typical car and was able to reach highway speeds, so he was needing similar performance to a standard car.

Not really. Most cars these days have *much* more power than the bare minimum they need to reach highway speeds.

The top speed of cars and bikes is determined by a contest between power and aerodynamic drag. There are other sources of drag, but at a high enough speed, aerodynamic drag dominates. What is this "high enough speed"? Well, for a car with a reasonably aerodynamic shape, maybe 100 km/h, for a naked bike probably 70 km/h, and for a cyclist maybe 30 km/h.

I happened to read a review of a small car in a random motoring magazine the other day. The car in question was a Citroen something-or-other, it had a 1600 cc engine generating 90 kW (a bit more than a 600 cc sport bike?) and this would push it along at a maximum of 200 km/h. OK, aerodynamic drag increases as the square of the speed, so if you double your speed you increase your drag by a factor of 4 and you increase the power by a factor of 8, yes 8. So at 100 km/h this Citroen should need 12.5 kW (a bit less than my Scorpio's maximum).

So: you don't really need all that much power to mooch around in a car on level roads; the fact that our DIY bloke's car could reach highway speeds doesn't mean its performance is anything like an ordinary petrol-engine car.

[imdying]

Not to mention the energy required to charge his batteries.Efficiency of the generation is improved though.

[Badjelly]

The article was very vague but instead of making my judgement based on that I took a look at the guys website instead (http://www.kiwiev.com).

Nah, the KB way is to speculate from a position of ignorance.

I see the motor is rated for 100 BHP (73 kW?) peak. A bit gruntier than I expected. I wonder how long he could run it at full power with the batteries he has. Not long, I suspect. Time to get the calculator out!

[Coyote]

Not really. Most cars these days have *much* more power than the bare minimum they need to reach highway speeds.

...
Didn't quite mean that it had to have the performance of a car in respect to being able to go well beyond the speed limit, but to have enough performance to go 100k like a standard car.

Interesting stuff. Now do you reckon it would be possible to make a DIY electric bike as this guy has done, or would I have to have oodles of money to get the ultralight batteries as standard ones would weight a bike down?


Nah, the KB way is to speculate from a position of ignorance.

Hoohoo, too right :p

[vifferman]

After reviewing the website, I must say I had to thoroughly revise my opinion of both the car and owner. I'm rather impressed by both.:doh:

[Finn]

Efficiency of the generation is improved though.

In New Zulland?

[imdying]

In New Zulland?Yep, even in New Zealand :yes:

[Finn]

Yep, even in New Zealand :yes:

Really? What are they doing, getting people to pick up the bits of coal that fell off the trains and burning those too?

Any, I just filled my SUV up with 98. Cost 180 bucks and I'll burn through that on the weekend. Kinda wipes out all the hard work this chap has done. Such is life.

[Badjelly]

Now do you reckon it would be possible to make a DIY electric bike as this guy has done, or would I have to have oodles of money to get the ultralight batteries as standard ones would weight a bike down?

Possible in some sense, obviously, but power/weight ratio *is* going to be a problem. Cars have a big heavy body, hence a poor power/weight ratio (compared to most bikes), but they retain reasonable open road performance because their aerodynamic drag is relatively low (compared to bikes). It's not just the more streamlined shape, but the fact that the frontal area of a car isn't that much more than a bike.

Given the heavy body that cars have to lug around (the car's body, I mean, not the driver's) a hundred kg or so of batteries isn't a huge problem. Scale it all down for a bike, though, and the batteries become a bigger part of the equation.

Does that convince you? It doesn't sound all that convincing to me, actually, but I don't have the time or inclination to do any concrete calculations right now.

Mind you, don't they have electric scooters in China? And here's a couple of links I found with Google:

http://www.enertiabike.com/
http://www.electricmotorbike.org/

The Enertia weighs 125 kg, max continuous power output is something like 6 kW (80 A x 76.8 V) and has 3 KW h storage from Valence Lithium Phosphate batteries (sounds impressive). Brembo brakes and Pirelli Sport Demon tyres--wow! Top speed 80 km/h (sounds about right for 6 kW). So at top speed it should be good for 1/2 hour, during which time it will have travelled 40 km. Quoted range is 70 km, which is reasonable given the lower aerodynamic drag at lower speeds. Only one gear, so acceleration off the mark is going to be leisurely. I wonder how much it costs?

[vifferman]

Mind you, don't they have electric scooters in China?
They have them here too.
But (however!) there are some problems (apart from quality). They are VERY popular in China, but apparently they're making/selling so many that there are very real problems (http://www.china.org.cn/english/Life/148781.htm) with the low-tech batteries they use (pollution from manufacture and all that), and with mental riders riding them.

[Coyote]

Possible in some sense, obviously, but power/weight ratio *is* going to be a problem. Cars have a big heavy body, hence a poor power/weight ratio (compared to most bikes), but they retain reasonable open road performance because their aerodynamic drag is relatively low (compared to bikes). It's not just the more streamlined shape, but the fact that the frontal area of a car isn't that much more than a bike.

Given the heavy body that cars have to lug around (the car's body, I mean, not the driver's) a hundred kg or so of batteries isn't a huge problem. Scale it all down for a bike, though, and the batteries become a bigger part of the equation.

Does that convince you? It doesn't sound all that convincing to me, actually, but I don't have the time or inclination to do any concrete calculations right now.

Mind you, don't they have electric scooters in China? And here's a couple of links I found with Google:

http://www.enertiabike.com/
http://www.electricmotorbike.org/

The Enertia weighs 125 kg, max continuous power output is something like 6 kW (80 A x 76.8 V) and has 3 KW h storage from Valence Lithium Phosphate batteries (sounds impressive). Brembo brakes and Pirelli Sport Demon tyres--wow! Top speed 80 km/h (sounds about right for 6 kW). So at top speed it should be good for 1/2 hour, during which time it will have travelled 40 km. Quoted range is 70 km, which is reasonable given the lower aerodynamic drag at lower speeds. Only one gear, so acceleration off the mark is going to be leisurely. I wonder how much it costs?
Bit like how a pillion on a bike is the equivalent of a car with 5 occupants and luggage.

A mate of mine has an RS125 race bike and rather than having a total loss system he has a dry cell battery. I was amazed by how light it was. If I did make some rough electric bike that could do with some weight loss I'd go so far as getting them.

Not sure about your Vespa-like scooters, but the kids type scooters have been around for a while. For example: www.ecobikes.co.nz

I have a minimoto rolling chassis. Might experiment with that first. Mind you there are already minimotos with electric motors out there so that project won't be that incredible, just have to raise the bar in speed I guess. Top of the line R/C car motors look wicked, maybe see if an upscaled version is available

[davereid]

Im certainly not going to argue with the "bosch handbook !"

But here is what we know...

It (the car) costs $2 for an hours motoring.

So at $0.20 a kw/hr he has purchased 10kw/hr.

That means the car, over the 60km/1 hr had the same power output as a wrung-out GN250.

Possibly a useable car....but not for me.

[barty5]

saw this item as well wonder how far he will be going in winter once he starts to use the heater?
second the car surly by the time he has pay for it from his saving the car will have rust out from under him shit the car is 20 years old now.
read an article in reguard to the toyota pirus the have worked out that the amount of damage it will do over it life span 10 years 100,000km (their estimate ) compared to a hummer with a life span of more lick 20 years 200,00 plus km the toy ota will in fact create more damage to the enviroment worth a thought.

[davereid]

The potential advantage of electricity over petrol is that the in-car efficiency (electricity -> motive power) is high and the generating efficiency can be substantially higher than a mobile engine can achieve (eg > 50% for a combined-cycle gas power station or ~ 30% for a coal-fired power station vs [what?] for a petrol engine).

Combined cycle generation is only of value if you have spare heat, or you need heat. If you built a diesel genset and used the heat to warm something up, you could claim similar figures.

Actually, diesel engines can do 50%, without hedging the data by claiming the waste heat is valuable.

See http://people.bath.ac.uk/ccsshb/12cyl/

[davereid]

Not really. He is using 12 car batteries which are recyclable. The footprint left from these will still be way less than years of petrol fumes.Even if you factor in the pollution caused by the generation of the power to charge the batteries, in comparison energy produced from a power station is still way more efficient (and therefore green) than that produced from a petrol engine.

The car batteries were most likely made from lead that was dug up by a big diesel digger, trucked to a refinery in a diesel truck, smelted by a coal fired smelter, shipped to you in an oil powered ship, and distributed around the country in big trucks.

And generally speaking, the power system is not really either green, or efficient. It has a massive reliance on oil and coal (NZ less than many places but still significant.)

And AC distribution of power is terribly lossy.

[Pixie]

Not really. He is using 12 car batteries which are recyclable. The footprint left from these will still be way less than years of petrol fumes.



Says who?

Greenie bullshit.
Producing the electrical energy - coal fired powerstation. we've already passed our hydro capacity
Mining the lead
Refining the lead.
Petrochemicals for the battery casings
manufacturing the sulfuric acid.
Repeat every 5 years for new batteries.

That covers the batteries.

now for the electrical power train...

[Badjelly]

Combined cycle generation is only of value if you have spare heat, or you need heat.

I meant a combined cycle gas power station where you have a gas turbine (literally a big jet engine) generating electricity and you use the exhaust gases to drive a steam turbine, also generating eletricity. These have very high efficiencies (50-60%) without accounting for waste heat.


And AC distribution of power is terribly lossy.

20%?


Actually, diesel engines can do 50%

Thanks for the data point. I'll read the link. Does this apply to in-vehicle use?


That means the car, over the 60km/1 hr had the same power output as a wrung-out GN250.

What people seem to have trouble realising is that vehicles spend most of their time using much less than the maximum power of the engine. Eg, the example I gave earlier: a small car that needs 90 kW to achieve its top speed of 200 km/h, but something like 11 kW (OK probably a little more) to do 100 km/h. About the same as a wrung-out Ginny. With petrol engines, in particular, this makes them inefficient. To reduce the power of a petrol engine you throttle it, literally, and a petrol engine on part throttle expends a lot of power sucking air against vacuum. Diesels are more fuel efficient primarily because their power output is controlled by cutting off the fuel supply, not the air supply. The idea behind a hybrid is to have a petrol engine running either at near full power or not at all.

[Badjelly]

Greenie bullshit.

Whatever. Try to put some numbers on what you're saying and it might be worth responding to.


Actually, diesel engines can do 50%.

I did look up the link. That's one big diesel! It wouldn't fit in Finn's SUV. The article also says most automotive and small aircraft engines have 25-30% thermal efficiency.

So basically, you're agreeing with me: with a whomping big engine, either diesel or gas/steam turbine, you can turn fossil fuels to motive power and/or electricity with an efficiency of 50%.

But you can't achieve efficiencies anything like that from an internal combustion engine in a vehicle, particularly with a petrol engine. So if you want to do better, your options are:

* Diesel: more efficient on part power.
* Hybrid: have the engine running at full power or not at all.
* Electric: use your whomping big, efficient engine to generate electricity and get the energy to the car via transmission lines, batteries etc.

[Hoon]

The car batteries were most likely made from lead that was dug up by a big diesel digger, trucked to a refinery in a diesel truck, smelted by a coal fired smelter, shipped to you in an oil powered ship, and distributed around the country in big trucks.

Yep much the same way a tank of petrol is produced and delievered to your car. The big difference is that this is a 3-5 yearly cost, not weekly.

I agree that at this point in time there is not enough benefits to justify changing to an electric vehicle. The advantages would need to be substancial to convince me and at the moment they are (arguably) only comparable.

However fossil fuels are running out, oil prices just keep getting higher and theres the pollution thing too. We need an alternative and EV looks to be a step in the right direction. The combustion engine is in its twilight years whereas EV is at its beginning so still has a lot of unlocked potential to offer.

So maybe not now but definately in the near future as the technology improves and the balance starts to swing.

[Fooman]

More fuel to the fire: I was at a seminar sometime this year on the future of NZ energy reserves (basically gasification of Southland lignite), and was talking to a guy from the EECA. He pointed out that using existing wave/tidal power plants, as recently installed in Portugal, and everyone converting to electric vehicles based on current technology (e.g. GM's Impact), NZ's vehicle fleet energy requirements could be meet by 150 square kilometres of wave/tidal power. Or approximately 0.01% of NZ's coastline. That is with inefficient transmission of electricity factored in (rather than conversion of electricity to hydrogen to power fuel cells etc). Capital costs would be quite high of course.

The other thing to consider with the above, is that when it was operating as a source of petrol (rather than methanol), the Synfuels Plant at Motonui major effect on the NZ economy was halving the balance of payments deficit from supplying automotive fuel domestically (via converted Maui gas) rather than importing from overseas. As it was doing this during a rather unstable economic period (mid to late eighties), the stabilising effect it had (on the order of 500 million dollars a year) was worth more in the long term than the large capital cost of the plant (think big). Since it stopped producing fuel, NZ went back to importing almost all it's fuel again.

Cheers,
FM