272: Saturday 13th September 2014

I set up my laptop with CAN software and linked up to the CAN Bus to get the battery voltage values. I tested each battery voltage and calibrated the CAN data to correspond to the battery voltage. I found the voltages were not changing at first. I think when I last fiddled with the measurement boards I didn't put them back together properly and I was 1 pin out on the connector. I carefully put it all back together and all the voltages were nearly right. I gave them a tweak using the calibration trimmers on the board so the hexadecimal values were representing the actual voltage measured for each of the 10 batteries. Unfortunately the display has a noisy power supply connection or a bad earth or something like that and I am getting some mush on the screen. It worked fine when it was powered from the USB port on my laptop, but when I hook up to the car, then it is glitchy. That's my next problem to solve. The image below is the background screen from the screen design program.
The actual display in the car with real data is much nicer than in the picture. The camera has picked up an interference pattern and reflections of my finger taking the picture amongst other things. slowly, but surely it is getting better and better. I also have the overall voltage working now so I can potentially get rid of the motor controller programmer box sticking out of the trim as I am  just using this to monitor the battery pack voltage in general. I shall fix the noisy power supply issue first.

271: Thursday 11th September 2014

I have been working on new designs for the battery monitoring display. I have come up with a real nice looking display that looks like a spectrum display with 10 bars and another bar for the overall voltage. I have not been able to get the serial signals linked to the bars at the moment. I have this working for the old configuration, so I just need to figure out what is different.
I have had some parts in my garage for a while now and I have just had a week in the sun in Tunisia and now I am having a week at home to unwind, so I thought I would get these parts fitted.
The secondary throttle spring was something I bought after I had my spring break and leave me with full throttle. Scary moments! I have been fitting an elastic band to return the throttle cable as the spring I made was a bit weak and wasn't always operating the throttle microswitch. Problem with elastics is they perish quite quickly. So I bought a long spring from ebay and fitted it today. I had to cut it as it was too long, but now it has a nice tension and always returns the throttle cable even if the spring on my throttle box fails again.
The other part that I got from ebay was a brake vacuum pump from an Audi TT. This type of pump is also used on VW Golfs and a variety of VW diesel engine vehicles. It is smaller than the chinese pump that it replaces and about 1/5 of the price. I paid £30 for this pump and £150 for my chinese pump. This was wired to the power steering pump as the chinese pump was not pulling enough vacuum to operate the vacuum switch. I tested the vacuum switch and it was working, cool. So I rewired the vacuum pump circuit back to the vacuum switch and now it works how I originally intended. When the vacuum is insufficient then the pump runs until the switch breaks and then the vacuum is good. this is linked to the main power circuit, so when the main contactor supply relay is active (key position 3 cranked) then the vacuum develops till the vacuum switch opens. When the brakes are applied the vacuum level drops, the vacuum switch closes again and the vacuum pump relay kicks back in.