# Considering Opel Calibra conversion



## Skovby (Sep 29, 2008)

Hello from Denmark everybody

I am currently considering getting a Opel Calibra (Holden/Vauxhall), and converting it to electric. 

I used this excellent calculator for figuring out required power: http://www.diyelectriccar.com/forums/showthread.php?t=20803&highlight=calculator

The Opel Calibra 2.0i 8v has a Cd value of only 0.26 and a frontal area of about 1.82m2. It weighs 1250kg (used 1400kg for added battery weight). I used a 19" Michelin Tyre for tire drag - Crr 0.00833. 

This all works out to 9.3kW at 100km/h and 17,5kW at 130km/h. (Does this sound right to you?) These are the typical speeds for my daily commute wich is about 70km each way.

I'm guesstimating that I'd need around 24kWh in the batteries for making the trip back home if I take about an 80% loss in the drivetrain (realistic?) and over time a further loss of 80% on the battery.

The engine I was thinking about was a ADVANCED DC #FB1-4001A rated for 28hp wich should keep me rolling at 130km/h. It weighs in at 64kg, and then I'd probably need ~40 kg for the rest of the electronics. 

If I remove around 250kg with the engine and related items (realistic?), that leaves 300kg for batteries.
So I need 300kg of 144v batteries with 24 kWh in them. Is there anything but really expensive Li batteries that will satisfy this requirement? If not I'll probably not do the conversion before the prices comes down.

Any thoughts on this project is welcome


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## madderscience (Jun 28, 2008)

Sounds like you've found a pretty good conversion candidate, and your calculations seem reasonable as does your motor selection. your calculated results are very close to the results I got when doing calculations for my car, and very close to my cars observed performance.

A CdA (Cd * frontal surface area) of 0.47m^2 is excellent, and is probably the most important factor of the chassis to consider if you are going to be driving at higher speeds (130km/h is 80mph!). My conversion (a 1985 toyota MR2) has a CdA of 0.53m^2 and that was just about the best car available in my price range in the US.

The curb weight of 1250Kg (2700lbs for us yanks) is a bit heavy but not too bad. If much of that extra weight is in the engine, a back seat, or other accessories you can strip out then it doesn't matter. You will be able to get the chassis weight back down. 

In the case of my MR2, the original curb weight was 2300lbs (1050kg).

I hope you will be able to charge at your destination because 70km (43 miles) is a pretty good distance to go on a charge with lead acid but if you could get the weight down and rolling resistance at 0.01 or less (I had to work at it to hit a measured 0.01, remember to consider brake friction, suspension movement and slight misalignment of the wheels contributes to rolling resistance too) 

with those aerodynamics it should be possible to do the 43 miles, especially if you could find it in your heart to keep your speed down to more like 100km/h. You should be able to recharge in 8 hours or so. My car (using 110v, 20A power) can charge at the rate of about 5 miles of driving per hour charging. I think you have 220 over there by default, but I don't know what a common circuit's current capacity is.

One thing working in your favor is as far as I know, there aren't many hills to worry about in denmark. but consider that strong headwinds ,might be a factor. Those headwinds were a killer when I rented a bike in Hamburg when I visited there last year.

Given your cold climate, insulated batteries will be a requirement, especially with lead acid.

If you can afford lithium, its a better option. If you go with lead, try to get at least 600kg of flooded (yes, flooded: better cycle life and energy density than AGM/sealed) batteries into the car. This means 22 to 24 6V golf cart batteries. If your car ends up like mine (a lead sled), you will lose about 20 to 25% of the total weight in removed components, and then add back 50% of the car's original weight in EV components and batteries.

I don't know how strict your government is about exceeding GVW. in Washington state, USA nobody cares. If Denmark's government cares, you are probably stuck with lithium because you won't be able to get the range with lead acid and keep the weight under the GVW I suspect, without abusing the batteries.

here's my car:
http://www.diyelectriccar.com/garage/cars/33

good luck.


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## Tommahawk (Sep 28, 2008)

Opel Calibra is a great choice, good aerodynamics but its weight is a concern for me unless I was using Li-ion polymer batteries


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## Skovby (Sep 29, 2008)

Thanks for your replies.



madderscience said:


> I don't know how strict your government is about exceeding GVW. in Washington state, USA nobody cares. If Denmark's government cares, you are probably stuck with lithium because you won't be able to get the range with lead acid and keep the weight under the GVW I suspect, without abusing the batteries.


I think you hit an important point here.. To make the car road legal in Denmark, you have to have it approved in a MOT test. What the requirements are for this is a bit unsure at the moment, since there isnt any real history of EV conversions. But, from what I've been able to gather it seems as if you wouldnt want to change the cars weight beyond the total max weight specified for the car. In the Calibra's case this is 1670kg, and you have to allow for the passengers weight aswell here. So the 1400kg I started with is probably the maximum 

Another problem here is that its really hard to know if the car can be made road legal at all, so paying maybe 25000$ or more for Li batteries would be quite expensive for an unusable car.
Maybe the way to go would be buying Lead Acid for the MOT Test - (just enough to make the car drive), and then swapping for Li if it works out.

For the weight stripping, I'm unsure of how much an engine weighs.. In this case its a straight four, 2 litre engine. The back seats will have to stay, as I need to be able to pick up the kids from daycare


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## Tommahawk (Sep 28, 2008)

Cannot find engine weight but found out that the 1990 Calibra has about 59% of its weight distribution at the front. 

Lithium Ion Polymer batteries will set you back about 6-8k for lead acid equiv range


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## RPieter (Jan 9, 2014)

Hello guys,...

Somebody still working on this project?  

I always want to convert a Calibra,...


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