Cambell Live - DIY electric car. Inspired?

[Badjelly]

The article was very vague but instead of making my judgement based on that I took a look at the guys website instead.

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

[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.

[Finn]

Efficiency of the generation is improved though.

In New Zulland?

[imdying]

In New Zulland?

Yep, even in New Zealand

[Finn]

Yep, even in New Zealand

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 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.