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Which cars are best thread.

Posted: Mon Jun 02, 2008 12:33 am
by AndyW
Would it be a good idea to have a thread of the best cars to convert. I was thinking maybe escort van or any of the lighter french vans of similar size. The fact that the rear would be a flat floor would help with battery location.

Is there a legality regarding where the batteries can go?

Posted: Mon Jun 02, 2008 6:58 am
by qdos
The word "best" is very subjective and depends very much on what you want to use the vehicle for. Just to be extreme here Jeremy Clarkson would say the Bugatti Veyron was one of the best cars in the world yet I've a friend who'd say it was his pushbike......

It's all subjective

Posted: Mon Jun 02, 2008 7:28 am
by MalcolmB
Good idea Andy, I've been thinking of doing something similar. Like qdos says it depends a lot on what you want from a car, but there are common factors that are important in choosing any battery vehicle. Most important are probably low weight and low drag.
I found a list of kerb weights for cars here: http://www.cuddles.abelgratis.net/kerbweights.htm
I'll see if I can find something similar for drag coefficients.
I've been looking around for a suitable candidate myself for a while. It seems that all modern cars are real bloaters. The original mini weighed around 620 kg, but the new one weighs in at 1130 kg! The same goes for the old and new versions of the Fiat 500. I'd like to start with something modern like a Smart Roadster, but even that weighs 800 kg.

The lightweight French vans could be a good choice at lower speeds. I've been looking around at old minis and mini-based kitcars, but there are some real rust buckets around.

Posted: Mon Jun 02, 2008 11:09 am
by qdos
The weight's list is a good point to work from Malcolm though there's a lot more vehicles out there besides the main manufacturers such as Kit cars and of course there's quadricycles too which a number of our members have typical weights for those are circa 400kg. My Zest is 370kg and my Ginetta G27 is about 600kg.

Drag factors I've no idea about what they are but it's good fun playing with different configurations in the zest as it's only 20 horse power (15kw) and you immediately see the results on the speedo when you change something it's great fun Just by dropping the height of the seat I get an additional 10km/h on the top speed and I'd like to fair in the rear wheels and see what that does much as the Honda Insight and the old Citroen CX DX were.

Stuart recently took the R2 to a wind tunnel and there's a report in one of the Kit car magazines about his experiments there. I'm sure he'll be happy to say something about what he found.

Posted: Mon Jun 02, 2008 11:13 am
by EVguru
Weight is important, but if you are going to do a conversion using lead acid batteries, then weight:volume ratio is more important. In many cars you will struggle to find room for lead batteries. A very easy conversion with a great weight:volume is a rear engined Skoda (Estell or Rapid). Forget all the jokes, whilst they may have been built from cheap materials, they're well designed and engineered. The didn't win their class in Rallying year after year for nothing. I put eight 85Ah leisure batteries in the back of one above the motor, eight more in the front and didn't even have to uprate the springs. There was room in the engine bay for four more, four to six more behind the rear seat, two more under the seat (tank area) and at leat two more where the radiator used to be. All this in a car that weighed 860Kg (dry weight) in its heaviest version.

Drag figures should be treated with a great deal of suspicion. Cd is used for marketing by manufacturers and it is in their interests to make the figures look as good as possible.

What we are actually interested in is drag. Drag is measured in force, Newton metres or pounds, at a given air speed.

Cd (co-efficient of drag) is derived from the drag force, air density and a reference area and is a way of comparing the relative efficiency of different shapes. The larger the reference area for a given drag, the lower the Cd. The reference area is usually the area presented to the airflow (frontal area), but where airfoil sections are being studied the total surface area, or plan area might be used instead. You cannot compare Cd figures derived from different reference areas to each other.

Calculating the frontal area of a car is complex, is it simply gross width times gross height (excluding mirrors or not?), or outline area, do you include the very turbulent flow under the vehicle? Exagerating the frontal area lowers the Cd. The MIRA wind tunnel used to be very popular becuase it had an excessivly thick boundry layer on the floor and gave low drag figures.

If you see a published CdA figure, that can be used to calculate drag with some confidence, since it incorporates the frontal area.

Posted: Sun Jun 22, 2008 10:10 pm
by Night Train
I was going to suggest the Skoda Estelle and Rapid for exactly the same reasons.

I have used and worked on a few and can vouch for their toughness and longevity. They ride better with weight in the front and so a mass of batteries in the front boot would improve things considerably.

The problem is finding one now. I used to have two high mileage Estelles with three engines between them collectively doing 40,000 miles pa on the motorways for three years. It was always an overheating, head gasket or oil leak problem, nothing else.

I haven't seen one available for ages now except concours standard collectables at silly money.

Posted: Thu Jul 03, 2008 4:30 pm
by AndyW
Surely a small mini van would be better that a Skoda. My wife had an Estelle and it was an awful car to drive and felt very heavy.

A french minivan would in my restricted experience be better plus a much nicer drive with plenty of room in the back for batteries.
Image

Posted: Thu Jul 03, 2008 4:52 pm
by Night Train
I know what you mean but I have a bit of a soft spot for the old Skoda.
I have also been thinking of a small pickup, like the Skoda Felicia pick up or the VW Golf Pick up, and using the load bed for batteries.

Posted: Thu Jul 03, 2008 5:14 pm
by AndyW
I have always seen VW's and Fords as heavy cars as they are well built and feel solid.

French cars are usually made from tin foil (or at least feel like it) so would be ideal for EV conversion.

I had a Micra once that was made from very thin pannels as is my sister in laws Nissan Almeira.

Using a van would be good as theres nowt in them to start with!! plus the batteries can site in the back where theres space.

Posted: Fri Jul 04, 2008 11:19 pm
by qdos
I can't help but think why bother going to all the trouble with a French Van conversion when there's the Berlingo already out there and in fact in this Issue of Plugged In there's a Peugeot Partner up for sale too at a very good price So look out for the mag arriving soon I hope. I'ts at the printers now and we've decided to give members 2 copies each this time so that you can pass on a copy to an interested friend or colleague etc.