WEEK 4: WOF and REGO, Simulation Battery, Testing Arduino for Battery Balancing

At the start of the week, I took the car in for a recheck at Clint Boon automotive to get the WOF which meant I could finally drive the car legally on the road, I also got 1 month of registration for $16.37 meaning it can be driven around in the meantime. I got an adjustment done on the wheel bearings also at Clint Boon and a proper headlight alignment which cost in total about $63.

I then got onto trying to design and build a battery balancing system, which I have decided against for certification and safety purposes, also found it rather complex and accuracy might be compromised with cheap micro-controllers. But I will still try work on temperature and monitoring controls with the Arduino for the programming side of this project. This may end up more costly, but safety is number one priority.

I also had an enquiry on the engine from the MR2, which I had another guy with my same name Stefan look at it on Saturday. If all goes ahead I will be removing the engine hopefully in the next week to get a better look and design of the engine bay of the car and possibly trying to swap it to their MR2. 

In mechanical engineering class I worked on test routing a steel plate for rebuilding the SmartDrive rotor with good result. I think this is one of the best methods for cutting out the new rotor as it requires perfect balancing and precision which the CNC router offers. I also managed to get ahold of several more motors from CREW Whakatane and I asked around to try source some more for the project. I took apart another rotor on the weekend and I will try to collect enough magnets to position in the final rotor.

Another thing I did was count all the batteries I have so far which I figured there are 681 li-ion cells in total so far with an average of 2000mAh each. This means in theory I have about 5kWh of energy storage for the vehicle so far which is great, but from calculations this is only the bare minimum but should get a solid range of 20-30km range which is awesome. I am still collecting and testing cells, and an idea of building the final pack with room for expansion came to mind at 1am in the morning as more range in future would be way better!

Before I start dismantling everything, I thought it would be a good idea to record a bunch of data on the cars current state such as suspension load and ground clearance and engine revolutions per minute in each gear for various speeds. I will work on recording this during the next week.

WEEK 3: Metal SmartDrive Rotor, Getting a WOF for car, Repainting bumper

This week I worked on constructing the metal rotor which encases the SmartDrive motor stator.
I had test CNC routered an end cap out of plywood which will be made of steel, welded to the surrounding magnet rotor.

My teacher Mr Smith is working on getting the plasma cutter going to try cut out the rotor surroundings more efficiently, which I roll in the metal rolling machine and weld the seam shut.

Anyway, the test strip, which I calculated the length wrong, I rolled into the rotor shape which happened to be too small (I used the inner magnet diameter instead of the diameter where the magnets attached), but I was still able to prove the effectiveness of the idea. I will continue working on this through mechanical class.



I also booked in a warrant for the car, which it failed on only a couple minor things thankfully, which was the wheel bearings adjustment, rear view mirror, headlights adjustment and brake light. I changed out the inner right tail light bulb and found a rear view mirror at CREW which had a very convenient suction attachment. These were only a couple of dollars which was nice ($5 for 2 brake bulbs and $2 for rear view mirror) which helped keep costs down.

I also tried aligning the headlights and tightening the front left bearing, but couldn't manage to do the front right bearing as one of the bolts was stuck on holding the assembly on. Anyway I will try get these repairs done at Clint Boon to get the WOF sorted.

Another thing I worked on was repainting the entire bumper with the cheap $4 gloss yellow paint from Supercheap Auto. This worked quite nicely and has helped the look of the paint a lot. The colour difference is noticeable though between the bonnet and bumper, but it is still a lot nicer than before.

WEEK 2: More Battery Research

This week I researched all the possible battery types I could use to power an electric car.

These included:
- Lead Acid
- Nickel Cadmium
- Nickel Metal Hydride
- Lithium Ion

I found out that Lithium Ion is superior in energy densities but also requires the most protective circuits to prevent catastrophic failure and damage to batteries.
Lead acid has the lowest energy densities which will make them less efficient in a mobile vehicle, but are also one of the safest and cheapest options.
I also found that lead acid, nickel cadmium and nickel metal hydride rechargeable batteries also typically have high self discharge rates, making them unsuitable for use over long periods of time. The self discharge can be as high as 10% in the first day for nickel metal hydride batteries.

I can source lots of 18650 lithium ion batteries from old laptop batteries, which I have been collecting over the past year. This is a cheap alternative to buying new and is more sustainable in recycling old batteries that 80% of them are still good. I have been testing each to record capacity which helps me to maximise efficiency when they are all wired together.

Term 2 WEEK 1: Rust Repairs, Researching Battery Types

The car is currently away getting a rust repair in the sills so I have not done anything on it for 2 weeks.

I began researching battery types to determine the best for my project. I have been testing and collecting the 18650 batteries from old laptop batteries over the last year as a plan to power the car from. I will still go through the process of researching the different batteries and their properties to narrow down to the best and most efficient battery type to use in my project.