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Discussion Starter #1 (Edited)
Hi forum members! It is my first tread after couple of years only reading, must give some help for others too. :) I live in Latvia English is not my native language. I am automobile (not electric) engineer. I have Citroen Berlingo EV converted to lithium and drive this car three years now.
From beginning, Mazda project target is efficiency, not impressive start or full speed performance, but I try to get maximum with one shut.
I use Chinese manufacturer GLELEC 30/70 kW water-cooled motor/controller combo, directly connected with final drive. It is PMAC 300 Nm 312 volt motor and weights 68 kg. All that gives 1330 Nm on driving wheels. Calculated max speed must be around 170 km/hr and must be tested later. Motor and controller is mounted in the fuel tanks place.
Batteries are 108 pcs Winston 100 Ah placed in the tunnel and front of the car. This ruined Mazda’s beautiful 50:50 weight distribution, but save trunk place and make car more usable. Car is not weighted yet, because is only 50% finished.
Short video from first drive: https://www.youtube.com/watch?v=ZptiL0ji5qo
 

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Very much looking forward to seeing more pictures of your project! I see you had fun spinning the tires on the snow...impressive for a build without a transmission and with a projected top speed of 170 km/hr- how you managed all that without a transmission will be very interesting to understand in detail.
 

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Discussion Starter #4 (Edited)
Tire spinning looks impressive, but it comes from controllers code. Originally this car come with very good traction control system, that did not work with electric motor. When tires loose traction controller keep build up speed. That is not so good for tire life and safety on road, but looks impressive. It spins on dirty concrete too, without snow.
Top speed expectations come from motor performance and my calculated car drag power charts, it is point where two lines crosses, real life can add some corrections in any direction.
 

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Discussion Starter #7
Specially on my request GLELEC programmed this little screen for me, or may be not only for me J. Long time I have no luck to get it work. Finally, I find that serial pin schematics given from them was a little bit wrong. Who has worked with serial connections in computer world knows how easy is mess send/receive wires.
 

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Class looks Great,

I look forward to more video.
I am very interested to know what you think of leaving the gearbox out, I two wish to convert a RX8 but never thought off removing the box, but this could lighten and give more battery space.
Does the car run out off power at 30+ mph or any issues with acceleration.
My thought would be to use AC drive so reverse would be easy with electric switch but one gear may be limiting .
Good work well done.
 

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Discussion Starter #9
I try to explain how I see this “one speed” approach.
At the early state of project research I found that minimum torque on wheels for car like RX8 (1400/1800kg) is around 1250 Nm. Divide it with final gear ratio 4.44 and I get that motor must have max torque around 300 Nm. That gives “normal” acceleration from stand still, even uphill, bet it is just below the numbers to allow you spin the tires on clean soft asphalt. OEM cars like Leaf or Volt can produce twice us much torq on wheels, but they are equipped with traction control systems. It is up to you leave gearbox or spend it. My decision you now. If I found that I need more power I can play with final gear later. There are many possibilities 4.44/4.6/4.78/5.125 that gives 1332/1380/1434/1537 Nm on wheels. Of course steps between numbers is small, but it is a possibility.
I put here my motors power chart.
Every 1000 motor rpm is approx. 27 km/h. Sweet moment is that max torq is from still to apr 60 km/h
 

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Hi
This is very interesting I am rethinking my approach I might go direct to Diff if a suitable AC can be fitted in and if price of Dff ratio change is not to bad.
Thanks
 

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Hi
This is very interesting I am rethinking my approach I might go direct to Diff if a suitable AC can be fitted in and if price of Dff ratio change is not to bad.
Thanks
RX8Spark,

look at those motors -http://www.enstroj.si/Electric-products/emrax-268.html

I am planning to use EMRAX 268 in my RX-8 conversion, direct to diff. Should have similar performance as Berlinger's but with top speed of 140km/h (with 400V+ system) or 110km/h (less than 400V system) and no changes to diff ratio required.
 

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note that all emrax motors, liquid cooled also - need air cooling, there are no way to cool all of the parts of the motor via liquid. This is a big disadvantage when compared to remy or siemens or other motors that can be cooled with oil, both stator and rotor. And it is an outrunner, so You will need to build a custom shell around the motor to prevent damage or something to the rotor.
 

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Discussion Starter #13
Somebody ask me to show how motor and battery boxes looks. Here it is. I put controller near the motor, to keep cooling system shorter and power cables as short as possible. Front motor support can’t be seen from this side, it is made from Toyota motor support.
 

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Hi Berlinger

That look a very functional set up, not eating into boot space, will leave the car very usable daily. I do not think your C of G will move that much forward to be a concern.
I may well take a leaf out of your book and go direct to diff if acceleration and top end not affected to much. This seem like the perfect set up. However as with all things it is a compromise and this looks like a very agreeable balance. I am very keen to here how you get on when it come to performance evaluation and how you find the practicalities of battery Monerating and management . In my work shop I have a pit and service access would work well for me.
Well done
Good Luck
 

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I like your build alot Berlinger. May I ask what you think about the quality of the motor kit? Do you have a link to the manufacturers information etc please? The motor chart you posted does not show. Thank you.
 

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Discussion Starter #18 (Edited)
Before follow my steps and go “direct” drive in that way pls double check your needs. My car is tuned for efficiency. Target is get 300 km range from this pack and will see how lucky I am.
It is sad that I can’t check performance on road, that will help a lot. Do not be impressed from tire spinning in video, it happens only because traction is low. With gearbox that Mazda can be a beast, but not now. J
About motor/controller. Uhh.., it is weary long story. I get their contacts in exhibition and it was in October 2013. Products is made very well, and it is the reason I start speaking with them. Shenzhen Greatland Electrics Co.,Ltd is name of this company. Most of info about company you can find in their site, and contacts too. Information about their products on site is poor, I have a brochure from exhibition and it is ten times more informative. If you now your needs just ask. Be aware that all communication goes true girls from marketing department. They are very trying to help, but they are not engineers. Lot of mistakes happen. Actually you can’t imagine how much… I get wrong drawings, wrong schematics and spend weeks after that to try find what is wrong. Controller can be used in analog or CAN mode, but you must choose it from beginning. It is full programmable, with many functions and possibilities, but I don’t now how to realize that if you do not speak Chinese, directly with engineer. Price is best in this story, it cost for me close to Solition/Kostov price….
 

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Hello Berlinger. Do you think you could scan the brochure and share it with US please? Also, sorry to be a bother, but can you post the motor chart in a different format like JPEG as I cannot view it. Thank you very much.

Also, may I ask why you chose a large vehicle like rx8 for range not smaller vehicle? Is it just space for batteries, or all family etc? Thanks
 
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