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Малко свършена работа.

07.03.2012

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Battery pack and other

06.03.2012

Тези дни работя над пакета батерии, или по-точно механичното им свързване. Все още се колебая за разположението на пакета в автомобила. Единия вариант е той да се намира отпред в коша, който е вече празен, а другия е отзад до мотора. Тук трябва да спомена, че проекта ще е със задно задвижване. Намерил съм заден мост от Пасат синхро и диференциал от Ауди 80 куатро. Мотора ще е директно свързан за диференциала и ще се намира някъде до мястото на задните седалки. Тоест тежестта на мотора и батериите ще се разпредели между предната, и задната ос, но по-близо до задната. Страхувам се, че предната ос ще остане много лека ,а това може да се окаже проблем при завиването. Предимството на това батериите да са отзад ще е в това, че ще се използват по-къси кабели от батериите до контролера за скоростта и мотора, а от там и по-малки загуби (пад на напрежение).

За пакета батерии ще използвам 280 броя от клетките които имам. И тук имам известни колебания за тяхната конфигурация. Вариантите са два : 56 последователно в 5 групи в паралел, или 66 последователно в 4 групи паралел. При първия разполагаме с по-нисък волтаж (184V номинално напрежение ) и по-висок номинален ток (28 Ah и максимален продължителен ток 1050А ), а при втория разполагаме с високо номинално напрежение (217V ), но по-нисък продължителен ток ( 840A ). Като тук не забравяме това, че тези клетки могат да удвоят максималния ток , но за не повече от 10 секунди.

При проектирането на механичните държачи се стремях то да бъде на модулен принцип така, че да мога да го конфигурирам във всеки един момент. За няколко дни измислих ето това:

 

Всеки модул се състой от две клетки. Всеки модул може да се свързва със всеки следващ последователно или паралелно на лего принципа. Все още се двуомя относто материала за изработка . Дали да е гитенакс или някаква техническа пластмаса.  Друг проблем, който имам с клетките е това, че са без изводи. Може да забележите това на първата картинка. Едното решение на, което съм се спрял е да пробия по 4 отвора М2, да им направя резби и чрез 4 болта да закрепя медните шини, който ще свързват клетките. Проблем е, че дебелината на материала където може да се пробива е около 3мм и всичко трябва да стане много прецизно. Самото пробиване ще се прави на CNC фреза и проектирах на бързо един държач:

 

Скоро ще покажа снимките след изработката им.

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“Ново” начало

Ето ни отново след почти 3 години затишие. Главния проблем, който трябваше на реша е как да се сдобия с висок клас клетки ( без да разполагам с космически бюджет ) и тяхното зареждане и контрол. Доста трудно , но с годините намерих начин да се докопам до мечтаните клетки. Главната причина за забавянето беше и в това, че в моя случай клетките са много на брои и специфични (около 300 броя 8ah A123 клетки за сега ). Когато се прави пакет от батерии е много важно да има контрол над всяка една от тях по време на заряд и разряд. Подобен проблем е стоял и пред инженерите разработили ТЕСЛА. Там също има огромен брой малки клетки. За съжаление не разполагам с техните инженери. Ако имахме да речем 60 клетки па 200Ah нещата щяха да са много по-прости, но за съжаление с характеристиките на този тип батерии не могат да се постигнат заложени за проекта параметри. За тези няколко години се сдобих с въпросните 300 клетки, който са специално проектиране за използване в хибридни и чисти електромобили (по-стария модел на A123 се използва в Тесла ). След доста експерименти и най-вече сметки относно финансовите средства необходими за решаване на проблема с контрола на батериите стигнах да решение на приемлива цена. На кратко за всяко отделна клетка съм се снабдил с отделно малко зарядно. 300 клетки, 300 зарядни. Така, че мога да каже, че вече няма пречки да започне същинската и “по-лесната” част от проекта, а именно събирането на всички компоненти, които вече имам и монтирането им в автомобила.

 

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Thunder Sky LiFePO4 batteries on sale now

21.06.2010

Since the 01.06.2010 we have the opportunity to offer on the bulgarian market a new, high-quality type of batteries for electric trucks, hybrid and entirely electrical automobiles.
The Thunder Sky LiFePO4 batteries have a list of advantages:

- High energy density;
- non toxic;
- 10 and more years of life;
- wide temperature range from -450 to +800 Celsius;
- up to 3% self-discharge;
- nominal electricity in discharge mode – 0,5C;
- maximum electricity in discharge mode – 3C;
- 5000 cycles of charging on level of discharge 70%;
- 3000 cycles of charging on level of discharge 80%;
- minimum voltage 2,5V;
- maximum voltage 4,2V;
- working range from 2,8 to 3,6V;

We offer also the BMS (relative systems for management of the battery charge), as well as charging device for the batteries.
BMS are equipped with a touch-screen controle module, electricity sensor, voltage modules, as well as CAN interface for the charging device.
For additional information, prices and terms of delivery, please contact us at:
e-mail: eltransbg@gmail.com
skype: eltransbg

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At last, fresh new toys from China.

28.04.2010

At last, fresh new toys from China.
The yellow battery is Thunder sky 3.3V 40ah on C1 mode. Maximum constant electric charge from 3C (120A). Lifetime 2000 cycles on DOD 80%.
The green battery is A123 3.3V 8ah on C1 mode. Maximum constant electric charge from 30c (240A). Maximum charge for 10 seconds – 480A. Lifetime 4000 cycles on DOD 80% and 1000 cycles on DOD 100% and 10C charge.
These days there will be data from the actual testing.

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Development

19.04.2010

The reason for this project to be taking so long is only one – batteries. It turned out that they are still the really problematic part that they have always been for automobiles. In fact it is exactly the batteries that get in the way of electric vehicles’ mass production. In the last 1-2 years these circumstances have changed dramatically. There are big technological breakthroughs in this field and the price is starting to get a bit more bareable. Bareable in such sense that when you draw the line at the end, it becomes worth it to build and drive an electric vehicle. The access to these new technologies is still difficult for the ordinary man. Tin batteries are already out of date and are not mentioned in contemporary serious projects. Until now I also totally exclude them from my plans. During these months I made numerous requests to companies that offer batteries. The conclusion that I made from all conversations and correspondences is a little disturbing. It is really difficult to work with European companies! The communication is a little bit better with the US ones. The truth is that the best communication turns out to be with the Chinese. While 80% from the European and US companies didn’t even bother to respond to my requests, the same rate with the Chinese is 0%. After an year of reasearch I realized that the best batteries for my project are the products of A123, but the access to their new prismatic cells is almost impossible. It’s not that they don’t produce them, they do, but they are intended for the big automobile corporations, that they have signed their contracts with and it is almost impossible for a physical person or a small company to obtain them. Only s few people in the world have managed to get a hold of certain quantities from them, but they have only a few pieces that are insufficient in order to gather a good set. After a persistent search I managed to get in touch with a Chinese salesman, who found another model of A123 (8Ah C1) which will do for now. After a few days I expect several pieces for tests and if everything is up and running I will build the power pack with the A123 batteries. The last piece of the necessary components needed for finally being able to start my hard work. Stay tuned for the start of the finish line.

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Batteries

13.01.2010

During the last year, there were many innovations that had crossed the path of the EVs. Almost all of the automobile companies started to develop electric vehicles or hybrids from EVs and gasoline engines. Many companies started the production of batteries for the EV industry in order to satisfy its need of energy sources. There’s no doubt that the lithium-ion polymer batteries are in first place. At the time being, according to my researches, this type of batteries is the most suitable to put into electric vehicles. And for now I’m totally dropping my first idea of putting lead batteries. There are two companies that deserve a special attention:  www.thunder-sky.com and www.a123systems.com .  Both of them are producing lithium-ion batteries, and naturally each one of these companies has its own developments and improvements that they had patented. You can even find an information that Tesla is using the A123 batteries, if you search the web. The advantage of the thunder-sky batteries is that they have big capacity on good price, but they lack the large current electricity, which is only 3C. A123systems on the other hand have less capacity for a certain price, but they have large current electricity – 30C. The conclusion is that the thunder-sky batteries are more suitable for family vehicles that don’t have any claims of having highly dynamic indications. On the website of a123systems we are informed of the new 20Ah Prismatic battery that’s on its way to the market. It has magnificent characteristics and it’s promising to bring a revolution in the EV’s world: 20Ah on 3.3 V, with max electricity of 600A and weight of 480 gr.

The mass production of this battery is expected to begin in June or July this year, and also at that time it’ll have a pretty good price.
For the moment, I stick to the idea of buying the batteries at the last minute, when everything else will be done. My observations show that any time now in this field there’s going to be a strongly dynamic boom, and if you rash with your choice and purchase, you may make a serious mistake.

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Disassemble and measuring

In the past few days, I began to remove parts that I find “unneeded” for my car.

sp_a11671

Then I tried to measure everything that I took off from the car, and that I had no intent of returning in it.

sp_a1165sp_a1173 sp_a1166

Here are the weights:

15 kg – exhaust system
1 kg – water reservoirs and tubes of the cooling system
6 kg – radiator with fan
9.5 kg – an empty tank
165 kg – a full equipped engine and gear box
Total: 196.5 kg

Soon I’m also going to take off the rear axle because I want to change it with one from VW synch. I’m also planning to put rear differential from Audi Quattro with differential lock. My idea is to make the car with entirly rear-wheel drive.
Expect pictures of their installation in the near future.

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A new acquisition – parts for the controller

29.04.2009

I had lots of problems and I had to wait a long time, but finally the parts for the controller that I had ordered from China arrived!

- IGBT SKM500GA128D

- Fast Diodes SKKE 600F

- IGBT driver SKHI 10/12

I can now start my work on the controller. The source of the PMW signal will be  PICAXE ; at least for now that’s my decision.The whole idea is to make two controllers. The first one will be 700 A and it will be mostly used for testing. It’ll be tested in a project for a civil electric vehicle. If the tests turn out successful, we’ll make the big controller (1400 A) for my project. Let’s just hope that soon I’ll be able to show you something that actually works. Recently I found out that I had problems with the gear box. Somehow I overlooked the fact that my motor was too big and my drive flanges would lean on the motor. For 4 mm less and it would have worked. I heard that the 084 gear box had a bigger shell than the 020 box. Any ideas?

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New design of home site.

19.03.2009

www.ev-bg.com

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The motor has been found!

27.02.2009

Quite unexpectedly, I’ve made myself a birthday present It’s the new model of an 11″ motor Kostov.

This is a more powerful motor than the one that I had in mind at the begging.

The motor that I wanted to use was a 22 KW at 144 V. And now I have a rated 35 KW at 168 V. I’ve heightened a bit my expectations….. The more, the better

I’d like to express my gratitude to Mr. Plamen Nakeff from ELPROM-EMS for his assistance during the purchase of the motor and special thanks also to TInko from the VW Club for his navigation!

Now I have to choose IGBT models for the controller. If there’s somebody who understands these kind devices, I’ll be very grateful if he contacts me! I’ve focused on the U series by Fuji: http://www.fujisemiconductor.com/html/table/91200/91227.htm

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What’s new?

12.02.2009

There was some kind of standstill during the winter season.
To begin with, I’ve ordered 2 very interesting books from Amazon.com
I’ve posted some up-to-date pictures to stimulate you!
This is a Curtis 1221-7405 400 А controller on 120V… or at least it was All the Mosfet (BUZ 30A) transistors have burnt. I found it in Stamboliiski town in some junkyard. It’s quite impossible to fix it, but also it’s too small for my purposes. Apparently here we have an overloading process that lead to the current state of the transistors. If even one transistor should burn out, all others will follow the example. It’s interesting to know who it’s made. They used lots of electrical condensers in order to increase the area through which the electricity will flow, and that’s a foxy trick. There’s no problem with putting only one capacitor, but its pinouts won’t let enough electricity pass. The pinouts of the capacitor are put directly on the power armature and this blocks all the inductance. You can see a scheme of the controller here:

http://www.evdl.org/docs/curtis_1221b_schematic.pdf

ELPROM-EMS have released a new series of motors and I think I’ll get myself one of these very soon

Expect more news soon

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The presentation of Tesla Roadster in Top Gear

16.12.2008

The presentation of Tesla Roadster in Top Gear

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Something I read

13.10.2008

These days I read some books and I found out some interesting things.

Max HP = reted Hp x 4

Max torque = torque at rated PRM x 9

Max Current = full load amperage x 5

These formulas concern the engine.

MAx HP = reted Hp x 4 – the maximum power of one electric engine is equal to its nominal power multiplied by 4.

In another book I read something interesting about the tires. The pattern of the tire has a great importance. For example of a suitable tire the book suggests GoodYear Invicta GL.

http://www.goodyear.ca/catalog/products/INVGL.html

As you may notice, the tire has radial pattern and it has a very little space of contact. By choosing the right model of tires, you can increase incredibly the past distance with only one filling of the tank.

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Tesla roadster

09.10.2008

www.teslamotors.com

Tesla roadster – for me this is the EV that will make its way into history. It’s like Tesla shouted to the world: “Look! Open your eyes!”. The batteries and the engine of Tesla produce 250 h.p. and a torgue of 380 Hm, further more the maximum torgue is available since 0 RPM. With just one charge of the accumulators you can travel for 350 km. Tesla starts and accelerates extremely quietly. And so, unconsciously, it reaches 14 000 RPM. The acceleration of 100 h.p. takes 3.9 sec, and the time of acceleration continues until the maximum speed of more than 200 km/h is reached. The whole idea of this car is to show the many advantages of this technology in regard to the already old conception of vehicles with internal combustion engine. It’s fast, powerful, economic and ecological! It’s something that none of the manufacturers can assemble in just one ordinary automobile. Here you can see some tables:

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