Showing posts with label Control Box. Show all posts
Showing posts with label Control Box. Show all posts

2009-09-05

Rack for Control Box and Charger

Behind the scenes  I was doing occasional test drives of my HR-EV for last few weeks. I don't have video of myself but I have video of my wife's EV-grin when she was first driving it which I'll edit and post it at some near time.
Testing was involving a lot of wiring and parameter tweaking to make more and more features of BCMS and car working. For temporary drives I placed control box on two wooden blocks across longerons of the car which worked quite ok but I don't have the photo of them - sorry :) Then I got to the point when I needed to have control box and charger fixed under the hood firmly for longer drives.
To fix control box and charger firmly I designed and built the rack from stainless steel square tubes. I didn't prepare any drawings or sketches for it since it seemed to be quite trivial task from design point of view.
The rack is basically two 30x20x2 stainless steel tubes across car's longerons connected with two bars and fastening loops for bolts at the end to fix it to the longerons. I used 3 stock bolt places on the car's body for fastening the rack and I had to weld in the fourth nut place where no other suitable option was possible. I drilled and welded in 8 bolts for places where Control box and charger will be fixed
The rack came out quite nice. Here are some photos of it.






The control box is almost finished. Next I'll need to make a cover for it. As you can see at the bottom on the sides are two bars with bolt holes for fastening control box to the rack.



The end of the box has all the connectors and cables. I can disconnect all the cables and take the box out for maintenance of itself or the motor underneath.



Here is the picture of rack placed with charger on it.



And here is the rack with control box on it. Of course control box and charger will normally sit together.


The whole construction came out sturdy but at the same time easily dismantable if maintenance would be needed. The intervention into chassis structure is minimum.

2009-05-04

Battery boxes and Control box

Battery boxes

As mentioned earlier I decided to place all the batteries underneath the car where the fuel tank used to be. After making measurements thinking and modeling I chose to make battery boxes to be fitted from underneath the car thus preserving most of the body structure and not weakening it with serious modifications. The reason is that I am thinking ahead about how I would present the car to inspectors who would be checking it to make street legal. Less modifications to the frame - less problems and questions asked.
So, I will make batteries trays/boxes fit and secure from underneath making only few openings from inside to complete the wiring once the boxes are placed in. There will be 5 battery boxes each holding 9 cells. Each box gross weight will be approx 32kg so it will be manageable to lift it to the car from underneath and secure it by hands of two persons. So you will be able put the whole 160kg of batteries box by box.
Here is the sketch of the battery boxes made with Google SketchUp:

Each box is a frame of stainless steel angle 20x20x3 with 0.8mm stainless steel sheet walls protecting the batteries from outside elements like water, sand and stones (remember they will be hanging under car's belly).
The production of boxes has started. I have made the welding jig to make their geometry solid. Without it would be very difficult to weld the steel boxes with decent precision and correct geometry.

Here is one of the boxes fit test with 9 ThunderSky cells. The cells have their contacts covered with tape - you don't want to short circuit expensive cell, don't you?

Control box


Control box is designed to hold all electronic equipment inside and provide a heat sink for controller and down converter. First of all I don't want any sensitive electronics or high voltage circuit hang outside where the could be touched by water, dirt or anyone's non-careful hands. Safety first. For example a session in car wash could lead to serious components damage or even fire in unfortunate circumstances. Therefore I decided to put all such pieces in one safe place - control box.
The control box will hold Kelly controller, controller cooling fans, DC 144V/13.8V down-converter, main contactor, circuit breaker, shunt resistor, throttle hall converter, multiple 12V control relays and fuses and BCMS master board. It will have two thick cables coming in from batteries, two going to the motor and low voltage signal cables going to many places.
The box is made from 10mm aluminium plate which makes base, 3 walls and internal spacer. The plates are bolted together by M5 bolts. The cover will be from 0.8mm stainless steel sheet.
The inside is divided by internal spacer wall into two sections: high voltage/power section and low voltage section. The sketch is shown in picture. There are two big black fans on top which are placed on the opposite side of the wall where the motor controller is placed for maximum heat dissipation effectivenes. The black box on the opposite side of the controller is DC down-converter. Both controller and converter terminals are placed so that they go out to the high voltage connections subsection on the upper right side of the box. This subsection is separated by plastic spacer plate which isolates the connections subsection to prevent any water or dirt entering there. Contactor, shunt and fuse are shown in this subsection. The subsection below contains BCMS board on the left and throttle pot on the right. Throttle handle is attached on the outside of the box. There will be gas cable connected to it.
The box will be put in the car above the motor in approximate location shown in sketch below. I hope you have enough imagination to see the yellow front of the car, black tire, red motor below and gray brakes cylinder assembly :).

Production of the box has started. The aluminium plates were cut (believe me it is daunting when you don't have the disk saw powerfull enough). A lot of drilling and threading was made.

Some power wiring was made with thick copper bars covered in yellow heat-shrink tubing. Production of each bar to about 1 hour - it looks small but eats your time very quickly.

A bit closer view. Note the two big holes drilled in the base - that's where the thick cables will go to the motor.

That's it for now. Some progress, not too much as I am really struggling to find time to sneak into garage and do some work on my HR-EV.