I'm not sure I understand Battery powered cars

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Bakudan
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I'm not sure I understand Battery powered cars

Postby Bakudan » Wed Jan 09, 2008 3:35 pm

I was just wondering if someone could tell me more about battery powered cars as I am very interested in them. I have a few questions that I would like to ask, and answers would be brilliant!
1. How much does a BV cost?
2. On average how long will a BV last on the road?
3. I am wondering about the battery size and roughly what it looks like.
4. Where would you put the battery?
5. How eco - friendly are BV's?

Thank you! :D

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dargles
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Newbie questions

Postby dargles » Tue Jan 29, 2008 10:57 am

Bakudan wrote:I was just wondering if someone could tell me more about battery powered cars as I am very interested in them. I have a few questions that I would like to ask, and answers would be brilliant!


Hi, Guys.
Er... how come this post hasn't been answered? I looked at this one because I would consider myself an EV newbie and thought I might get some answers to my questions as to where to start. The language (like "EV" :shock: ) is a bit difficult to get one's head around, and there are loads of questions to ask.

First of all - Bakudan - I am a newbie, but I guess I might have answers that at least others can correct :wink:

1. How much does a BV cost?

How much do you want to pay and what do you want? There is the Tesla at $100,000, or at the other end of the spectrum, there was a milk float on eBay recently for about £250...

2. On average how long will a BV last on the road?

How long will any car last? Longer if it's got aluminium/fibreglass panels, if it's garaged, if it's serviced properly... It's just a different power plant.

3. I am wondering about the battery size and roughly what it looks like.

Ah, now that's a good question. The Tesla has Lithium Ion batteries (lithium something, anyway) which are like your mobile phone and will be more compact. Old milk floats will have lead-acid (car) batteries which will be horrendously heavy and have poor characteristics (like having nasty acid spilling around - that helps to demolish your vehicle if it spills, see 2)

4. Where would you put the battery?

I'm sure the guys on this forum have loads of ideas about that. As far as I'm aware, the general answers are:
* in the boot
* under the bonnet
* under the floor
* anywhere you can find a massive space going free

5. How eco - friendly are BV's?

It's not as clear cut as it might seem. The vehicle itself ought to be 100% green, except that it apparently produces CO2, and as far as I'm aware, it also produces ozone (yum yum - the London underground smell; not to everyone's taste...) Although ozone might be considered good in that it might replace the ozone layer, apparently it doesn't do that and is actually a pollutant. Shame.

But the big deal is that the electricity has to be produced somehow, and that means power stations, together with a less than 100% efficiency converting from one form of power to another.

But in the final event, an electric car has to be the greenest form of powered transport around.

Thank you! :D


OK, guys, time for you to pitch in and correct my newbie ideas!

But my questions were going to be:

1) I reckon you could get 2CV performance and 100 mile range with a 6kW motor and 10 x 56Ah car batteries. Where can I find information about electric motors? I'm not having much success so far, trawling the net.

2) I reckon better still would be Li-Io batteries, something like 2000 Li-Io 2Ah AA batteries strung together. Has anyone tried going down this route? I know it would be very expensive (maybe about £3000?) but could be interesting?

Regards, David

ChrisBarron
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Re: Newbie questions

Postby ChrisBarron » Tue Jan 29, 2008 11:41 am

I'll comment about the non-cosmetic issues. My wife tells me I have no style and honestly, I have to agree there !


2. On average how long will a BV last on the road?

How long will any car last? Longer if it's got aluminium/fibreglass panels, if it's garaged, if it's serviced properly... It's just a different power plant.


I expect electric vehicles of the future likely to outlast conventional internal combustion vehicles simply because they have fewer moving parts in the drivetrain, and what moving parts they do have can be replaced quite easily and cheaply.

The major cost comes from the cost of the batteries.
When you factor in the replacement cost of batteries and the cost per mile in electricity, compared to internal combustion engines and the petrol costs over the same distance the difference is quite startling.

Assume you have a high end battery pack, costing £4000 to replace, and it lasting only 50,000 miles (conservative), and you pay 3p per mile in electricty, the costs over the 50,000miles are £4000 + £1500 = £5500

Assume you have a petrol engine which dies at 100,000 and costs £1000 to replace, an interpolated cost of £500 for the engine at 50,000 miles seems acceptable. Assuming you get 35mpg, and do all 50,000 miles at £1.05p per litre, your 50,000 miles cost (6500 litres X £1.05) £6825 for fuel and £500 for the engine. Then you have five services in those 50,000 miles (first one free), at a conservative estimate of £150 including parts and labour (including one timing belt service) and thats another £600, or about £8000.

Then assume you are doing only 10,000 miles per year and you have to think about 5years of road tax difference too

(Typical Yorkshireman here, always looking at life in terms of costs)


5. How eco - friendly are BV's?

It's not as clear cut as it might seem. The vehicle itself ought to be 100% green, except that it apparently produces CO2, and as far as I'm aware, it also produces ozone (yum yum - the London underground smell; not to everyone's taste...) Although ozone might be considered good in that it might replace the ozone layer, apparently it doesn't do that and is actually a pollutant. Shame.


2 years ago the estimate of offset CO2 production for electric cars from the power utility company/electricity provider was about 46g of CO2/km of travel, which makes them the lowest CO2 producer of all cars. But of course, this is only true for places where the majority of electricity is produced when large amounts of coal ( over 30%) are burned. In Scotland we have about 18% renewably sourced electricity (according to www.theiet.org) so our CO2 rate per kilometre is going to be down in about the 30-35g numerical region.
Any offsetting of CO2 coming from home generation is going to carve right into that too.

Although not directly relevant, carbonated soft drinks and lagers release about 24g of CO2 per litre, but of course that CO2 was taken as waste from industrial processes or compressed from the atmosphere, so in effect it is existing CO2 which is being temporarily sequestered. However if those industries producing the waste CO2 just released it they would be hit with a bill, so in effect they are smuggling it out of the back door, and the drinks makers do not have to pay premiums for releasing it !


Ozone from the motors is minimal, and is comparable to the amount produced by a typical laser printer running for the same amount of time. Luckily the industry which developed electrostatic printing also campaigned to fit 'ozone filters' to their printers, and the same devices can also be fitted to a motor if ever it was thought to be a harmful situation. The filters contain nothing but cheap old activated carbon, high can be both abundant and cheap.



But in the final event, an electric car has to be the greenest form of powered transport around.


Agreed !

OK, guys, time for you to pitch in and correct my newbie ideas!

But my questions were going to be:

1) I reckon you could get 2CV performance and 100 mile range with a 6kW motor and 10 x 56Ah car batteries. Where can I find information about electric motors? I'm not having much success so far, trawling the net.


6kw is about 8HP. It takes about 10-12HP to push a typical car along through the air at 50mph. This doesn't mean the motor will not do the job, it will be running at above it's rated load though, which is not an issue if you only want to do that for 15 -30 minutes.

At the load a car would demand your 56Ah batteries will appear to be 35Ah batteries (approximately speaking), due to the Peukert effect, which says that the faster you draw power from a battery the lower it's overall capacity. At 120V you have about 4.3kWh of capacity. Assuming your consumption is at the rate of 200Wh per mile your range is about 21 miles, if you keep your rate of acceleration down to 2CV levels.

The real world figure would depend on the route, inclination/declination, and temperature of the cells (not so much an issue with battery warmers and insulation) and you could get a real range of anything between 15 and 35 miles. Driving style is the single most important factor when considering range. Harsh acceleration creates wasteful heat and wastes power if you didn't need to really accelrate quite so quickly, which is why regenerative recovery systems impact fuel consumption in hybrids so much when the regen'd electricity is used during subsequent periods of acceleration


2) I reckon better still would be Li-Io batteries, something like 2000 Li-Io 2Ah AA batteries strung together. Has anyone tried going down this route? I know it would be very expensive (maybe about £3000?) but could be interesting?


Tesla do something similar. The only problem is that ,ideally, each cell needs a battery monitoring device to keep it working at it's best. It's fiddly and expensive, which is why larger capacity cells are preferable.
I was looking on eBay in the States and you can buy 11Ah D-cell, NiMH batteries at 8 for £20 from time to time. They're about £2.50 each , and to make a pack like the one discussed above would use about 500.
I don' think the maximum discharge rate is very good though, so maybe that is why nobody is building big packs from them

Chris
http://tinyurl.com/39q5jd How to properly label keys :o)

Bakudan
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Postby Bakudan » Tue Jan 29, 2008 7:12 pm

Thanks for your answers! I have a clearer understanding of battery powered vehicles! :D

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ChrisB
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Postby ChrisB » Tue Jan 29, 2008 7:41 pm

I think something that everyone forgot to say about is the "EV grin"

Its very bizzare but I think everyone gets this, sit in a electric powered vehicle, be it a Car,Van, Bike, Motorbike or what ever, YOU WILL get a big grin on your face when you drive off in almost silence 8)

Anyone want to deny the EV grin ???

ChrisB
I reject reality and substitute my own !!!!!!

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dargles
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Newbie Questions

Postby dargles » Tue Jan 29, 2008 7:50 pm

Hi - Yes, thanks, Chris, that's really most helpful.
I sort of felt that there must be things that would stop one from getting the theoretical maximum and you've explained that well, thank you.

The problem with having a range of 20-30miles is that it makes the vehicle only useful for shopping trips - I couldn't even do local work trips on that range. The Tesla seems to have solved the problem, but at 50,000gbp, it's out of reach (and how long is the waiting list... ?). I guess I have to be patient for now...

Are there folk who've managed 100 mile range and sensible performance (2CV performance would do fine...) all packaged up in a practical car?
Regards, David

++++
Crossed posting:
Yes, ChrisB, I haven't experienced it (the EV grin), but can imagine it. I have childhood memories of London Transport Trolley Buses back in the 50s. They were *very* nice!
Regards, David

ChrisBarron
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Re: Newbie Questions

Postby ChrisBarron » Tue Jan 29, 2008 10:26 pm

The problem with having a range of 20-30miles is that it makes the vehicle only useful for shopping trips - I couldn't even do local work trips on that range. The Tesla seems to have solved the problem, but at 50,000gbp, it's out of reach (and how long is the waiting list... ?). I guess I have to be patient for now...


I was really only playing with the numbers being suggested from using 10 small car starter batteries. A larger battery pack will give you more range for sure. There is a weight premium to pay, in particular for lead acid, and that impacts acceleration power requirements more than it does the power required to run at speed, but ultimately lighter is better.

In saying that, I have 25 160Ah 6V cells I would like to use in a 4x4 or pickup. Allowing for Peukert effect I will have about 18kWh (more if the terrain is all flat). If I allow a consumption of 350Wh/mile I will get about 50 miles of range. I'm looking at hybridising something too, to make a diesel electric, but we're already a two car household so we would have one car for the exceptional journeys and therefore all electric would work because my commute is rarely more than a 45mile round trip, and there is a slim chance of getting charge at the halfway point should it be needed.

If I could get lithium I would be happy, I would pay todays price and buy them right now if I had the money, but in the meantime my £250 pack of lead acid will have to do.

Here's a video of Tom Hanks in his electric car http://tinyurl.com/ys3c7x
It's a real large family electric with a 100mile range. It uses AC propulsion's AC150 drivetrain, which isn't cheap but is all good

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ChrisB
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Re: Newbie Questions

Postby ChrisB » Tue Jan 29, 2008 10:33 pm

dargles wrote:Are there folk who've managed 100 mile range and sensible performance (2CV performance would do fine...) all packaged up in a practical car?
Regards, David


Anythings possible if you throw enough money at it :wink:

We have a member (Alan Ward) who runs a Fiesta (my old one) which is now filled with Li-ions and he regualarly gets 100miles and that vehicle has a top speed of 75mph 8) although you wont get both at the same time :wink:

ChrisB
I reject reality and substitute my own !!!!!!

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qdos
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Postby qdos » Tue Jan 29, 2008 10:38 pm

I'm going to be a tease here relating to range and say We're working on something :wink:

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qdos
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Re: I'm not sure I understand Battery powered cars

Postby qdos » Tue Jan 29, 2008 10:49 pm

Bakudan wrote:I was just wondering if someone could tell me more about battery powered cars as I am very interested in them. I have a few questions that I would like to ask, and answers would be brilliant!
1. How much does a BV cost?
2. On average how long will a BV last on the road?
3. I am wondering about the battery size and roughly what it looks like.
4. Where would you put the battery?
5. How eco - friendly are BV's?

Thank you! :D


1. Generally more than an equivalent petrol/diesel but effectively you're paying for the fuel in advance really in the form of the batteries recharging them is a fraction of the cost of petrol but of course you've paid a lot for them in the first place.

2. As with a petrol/diesel it depends on the owner. A clue though is look at the the average age of a milk float they can go on and on and on.

3. They vary enormously but can be more than one

4. As with 3. They can be placed in many positions not just in the engine bay or where the petrol tank usually sits. They can go anywhere.

5. Whatever fuel supply you power your car with the energy used had to be brewed or generated some how somewhere. However! electricity can be generated by many many means and you can make your own if you want with solar cells and wind turbines though it won't amount to much but you get the gist I'm sure.


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