Развитие

19.04.2010

Причината този проект да се забави толкова е само една: батериите. Оказа се доста проблематична част, както винаги е била за електромобилите. Всъщност именно батериите са спънката елетромобилите да не навлязат масово. Последните 1-2 години тези неща драматично се промениха. Има голям пробив в технологиите, а и цената започна да става малко по-нормална. Такава, че човек като тегли чертата на разходите наистина да си струва да кара електромобил. Все още достъпа до тези нови технологии за обикновения човек е труден. Оловните батерии вече са отживелица и в никой по-сериозен проект не се споменават. Аз също за сега тотално ги отписвам от плановете си. През тези месеци направих безброй запитвания до компании, който предлагат батерии. Изводът, който си направих от всичките проведени разговори и кореспонденции е малко смущаващ. Много трудно се работи с Европейски фирми! Малко по-добра е комуникацията с американските компании. Истината е, че най-добре се работи и комуникира с Китайците. Докато 80% от европейските и американските фирми изобщо не си направиха труда да отговорят на запитванията ми, то този процент при китайските фирми е 0%. След година проучване установих, че най-добрите батерии за моя проект са продуктите на A123, но достъпът до техните нови prismatic клетки е почти невъзможен. Не, че не ги произвеждат, произвеждат ги, но са предназначени за големите автомобилни корпорации, с който подписаха договори и е почти невъзможно човек или малка фирма да се сдобие с тях. Само няколко човека в света са успели по неведоми пътища да се снабдят с количества от тях, но и те имат доста малко бройки, което е недостатъчно за да се събере добър комплект. След упорито търсене успях да се свържа с китайски търговец, който намери един друг модел на A123 (8 ah c1), за сега ще ми свърши работа. След няколко дни чакам няколко бройки за тестове и ако всичко е нормално ще изградя захранващия пакет с тези А123 батерии. Последното звено от необходимите ми компоненти, за да започна усилена работа. Очаквайте скоро началото на финалната права

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.

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?

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

The basis of the EV

08.10.2008

Today we’ll have a bit of theory. What are the basic elements of an electric vehicle (EV)? They are:

· batteries

· controller

· electric engine

If I have to compare the different parts of an EV and a normal petrol car, then the batteries of the EV should be the tank in the normal car. The energy is stored in the batteries and later it will be transformed in some kind of mechanical movement. The controller serves to command the electric engine. It determines the velocity of rotation of the electric motor. It has the same aim as the carburettor. It measures the fuel depending on the velocity we’d like to reach. In our case, the given fuel is the voltage of the batteries. The controller can perform other tasks just like the other controllers in the modern automobiles. The electric motor itself is simple If I have to be more specific, the electric motor has a moving part – a rotor and an immobile part – a stator. Just one electric motor has much less moving parts than an internal combustion engine. It has a bigger efficacy, but I’ll write about this in a separate post.