# Planning VW Golf Rabbit / MX5 Miata NA conversion



## ivaniclixx (Apr 11, 2010)

Hello,

My name is Iván. It's been a month since I'm trying to sell my current and only car so far (Mazda MX5 NC), in favour of an electric car.

Because the available options from major car makers companies are expensive and sometimes too ridiculous, I'm planning to do my own car conversion starting from a second hand bought car.

The first thing I'm taking into account is the homologation of the car; here in Spain It's almost impossible to take and ICE car, convert It to electrict and make It legal. The most reasonable option I think I'll have is to buy a portuguese, french or german car, legalize It there and then import It to Spain. But, well, that's not the question.

I have lots of doubts regarding my conversion, but I'll start with my idea here, and any help will be very much appreciated.

Oh, and yes, my English is terrible, so please don't be cruel with me .

My initial thought was to buy a cheap and second hand MX5 NA and convert It, because:


It's funny to drive.
It's rear wheel driven.
It weight just around 950Kg stock.
It's the most similar to my current car, which I'm in love with.
A lot of people already converted Miatas to electric, and there're even specialized kits for It.
etc.

But thinking about Its practicality, maybe a much more reasonable car would be a VW Golf, or similar cars.

About desired characteristics:


AC system: no doubt, I want a three phase induction motor with regenerative capability.
NiMH or LiFePO4 batteries: I would prefer to use NiMH batteries, as the used by Toyota RAV4 EV, but as they're not "sellable" anymore, I've seen that Nilar sells big NiMH battery packs, but they're more expensive even than LiFePO4 ones...
Enough power to move the car from 0 to 120Km/h using the same locked speed (maybe 3rd or 4th); this is, around 20Kw or 25Kw nominal should be OK I think.
A range of 150Km./200 Km. per charge.
BMS !
I should spend no more than 15000 Eur./20000 Eur ($20000 / $25000).

I'm doing a list of possible components for the car. Here they are:


 EVE M2-AC30-L 30Kw 288v 3 phase AC motor, http://www.electro-vehicles.eu/shop/details.asp?prodid=EVE02&cat=0&path=47,60
Mes-Dea TIM600W AC-DC controller, http://www.electro-vehicles.eu/shop/details.asp?prodid=MES04&cat=0&path=48,63
LP100Ah 12v 100Ah x 24, http://gwl-power.tumblr.com/tagged/quote

I need to know more about the BMS (would It be enought to have those simple circuits between serial connected batteries? I don't know), and a charger.

Please comment anything you see good/bad about those specs and so on.

Thanks,

Iván.


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## ivaniclixx (Apr 11, 2010)

Wow, I wasn't expecting zero replies to my topic, but well, It doesn't matter.
I've "switched" my AC motor/Controller preferences after reading the pathetic support from MES-DEA people referring to Its products.

What do you think about this: http://www.evparts.com/products/street-vehicle/motors--dot/48-to-96-volt-street-vehicle-motors/mt5615.htm?
I've posted an spreadsheet on google docs here:

https://spreadsheets.google.com/ccc?key=0AjoJvwy9eZXRdE1nSm1tZ3hQd2RXRWRwRHV2WlFjekE&hl=ca

Any comments are really appreciated.

Iván.


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## Duncan (Dec 8, 2008)

Hi Ivan

I am aiming for a similar budget - but that means DC

I just don't think AC is doable on that budget

My budget

Car - $1000
Motor - $100 (ex fork lift)
Controller - $3,500
Batteries - $12,000
Charger/BMS - $3,500

Total - $20,100

I bet I end up over $25,000


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## ivaniclixx (Apr 11, 2010)

Duncan said:


> Hi Ivan
> 
> I am aiming for a similar budget - but that means DC
> 
> ...



Why not? Have you seen my spreadsheet? AC motor + controller = $4500.00
Another $12000 for batteries + mini BMS, a charger for about $700... That's a total of about $17200 in parts (10314€).


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## PatricioIN (Jun 13, 2008)

even with lithium batteries, your range requirements are difficult. A miata is only so big and only capable of carrying so much weight. I've owned two NA miatas and the are very fun to drive! I'm not saying it can't be done. I just think you'd be happier in the end if you lower your expectations on range. Also, if you're really planning on spending that much money, why not just buy a Nissan Leaf?


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## ivaniclixx (Apr 11, 2010)

PatricioIN said:


> even with lithium batteries, your range requirements are difficult. A miata is only so big and only capable of carrying so much weight. I've owned two NA miatas and the are very fun to drive! I'm not saying it can't be done. I just think you'd be happier in the end if you lower your expectations on range. Also, if you're really planning on spending that much money, why not just buy a Nissan Leaf?


Because a shitty Leaf will be (if buyable anytime soon here in Spain) about 35000 eur after federal taxes ... And Its 160Km range is quite optimistic; at highway speeds Its range is going to be about half of It... With 1600Kg and a 24kwh battery pack... Too much money for still a very limited in range car.

Apart of that, I like the idea of spending money directly to improve my own car batteries -an Its range-; as time goes, prices are going down.


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## tomofreno (Mar 3, 2009)

Hi Ivan,

I used the AC50 for a conversion of a small car, Suzuki Swift, 1020 kg final ev weight. It works very well for me. I have a thread in the Builds and Conversions forum here entitled "SwiftE" and the car is also at evalbum.com/3060. I should add that most of the data at those places was taken during winter with cells at about 10 - 15 degree C, and range and performance are better in summer due to warmer cells. Range in summer for mixed highway/secondary road driving is more like 70-80 miles (~125 km). The car has good acceleration, but it is not a sports car that does 0 to 100 km/hr in 10 seconds or less. More like 16 seconds in summer, little slower in winter. A heavier car will perform proportionately less. Every once in a while when someone notices the car is electric at a stoplight, it is fun to take off and leave them behind to change what I imagine is their image of electric cars being slow. A current draw of 400 - 450A is usually sufficient to do this. I am using 36 180Ah CALB cells for nominal 115V, 20.7kWh. My conversion cost about $23k U.S. dollars. The EVE motor appears to be considerably higher power, which would give greater acceleration for maybe 40 - 50% more cost than the AC50. It is also water cooled for those hot days in Spain.
Oh, I am also using the minibms. It works well. Best I can say is it is just a car now. I get in and drive each day without thinking about much of anything. Plug it in at the end of the day, hot tub timer turns on power to the charger at night. In the morning I unplug, get in and go. Once a month or so I check cell voltages for balance, but it is pretty boring anymore.


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## RKM (Jun 9, 2008)

PatricioIN said:


> even with lithium batteries, your range requirements are difficult. A miata is only so big and only capable of carrying so much weight. I've owned two NA miatas and the are very fun to drive! I'm not saying it can't be done. I just think you'd be happier in the end if you lower your expectations on range. Also, if you're really planning on spending that much money, why not just buy a Nissan Leaf?


I'm with PatricioIN on this. I converted an NA Miata (search "Miata's last gas(p)"). I have 45 TS 180Ah cells arranged in 5 boxes throughout the car. There is virtually no more room for cells, without forfeiting all the trunk space. Further, the car gained 500 pounds and I needed to upgrade the rear suspension. The 25Kwh pack is good for about 100-120 kms of range, IMO. I think you'd be hard pressed to get 200 kms.

I don't want to discourage you, but wanted to share my experience.

Good luck.

Rob


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## ivaniclixx (Apr 11, 2010)

@tomofreno: your car looks great! But I see you're using the original gearbox... My first though was to lock It in 3rd or 4rd gear, have you tried starting and running the car in a single speed?

@RKM: ok, so It looks like It's not a very good idea to try to convert a Miata If I want more mileage... But man, I've sold mine a week ago and I am already missing It so much. I won't have so much fun with any other car.

And for the 25kwh pack, I though It was going to be enogh to go 200Km on a single charge. Maybe with something bigger, like 35kwh? I could start with a 22kwh pack and see how It goes.

About the car, If not a Miata or a VW Rabbit, do you know a 5/4 seat cheap and secure (4/5 euroNcap stars) car that is RWD? Except for RWD, an Smart Forfour maybe?

Thank you everybody for your responses.


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## ewdysar (Jun 15, 2010)

As far as range is concerned, it depends on your speed.  If you're driving on flat land, and staying below 50Km/hr, then you might see 200Km near the end of your proposed battery pack (20kWh usable). Going faster or dealing with hills will severely reduce that range. In a very efficient conversion, you might be able run as low as 130Wh/Km at 100Km/hr, again at constant speed on flat ground. That works out to a theoretical 153Km usable range under optimal conditions. The problem with adding batteries, if you could find the room and the vehicle could handle the weight, is that your energy consumption will go up too while your performance goes down, especially under acceleration and going uphill. 

Eric


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