WEEK 7/8: Wiring up 27 Battery Modules! Spot Welding and Soldering Fuses. Making Copper Lug Terminals. Rotor Prototype Working.

Over the next week, I worked hard at getting all the battery modules wired together.
This proved to be rather tedious task with all my DIY setups, but I managed to get it all done in the end after maybe 20 hours of hard work.

My process included cutting 63cm segments of 6mm2 2C + E wire; stripping each individual wire; removing 2 strands of the thicker wire; doubling over the wire; twisting wire; cable-tying to modules; stapling other end; cutting 1/4W resistor legs; spot welding to cells over copper bus wires; soldering to wire; repeating last couple steps for each module.

And doing this 27 times! The repitition is hard, but should be well worth it.

Anyway here are the photos from wiring up the batteries!

 My next step will be to make the copper lug terminals for the end of each module from the scrap copper I got from McCauley metals Whakatane!

After cleaning them up, I got to making the terminals on the weekend.

After coming up with a copper lug terminal design I was happy with, I got to making 58 of these (couple extra just in case).

Steps I took in making these:

cutting 4.5cm bits of pipe;

cleaning inner tube;

flatten 2cm in vice;

drill 8mm hole;

round edges, deburr;

final clean;

This took me a 2 or 3 minutes to make each one, so I was finished in just under 5 hours.

So yeah, another lot of work!

After fabricating all these lug terminals, I crimped them on to each battery module, by bending the wire end of each module to fit the terminals and squishing them on tight!

I am happy with how these are turning out, and after another hour or so, all 27 battery modules were now kind of complete!

My next step would be to test wire the modules together with the BMS to see how it is all looking.. and finally insulate the modules and install them into the car!


I also fixed up the rotor wobble as best I could by welding strategically to contract areas and 'pull' them into position. This worked OK, but the rotor is likely unsuitable for an electric car at present. I want to get it remade properly, and use the idea to manufacture a much better version that can push lots more power!

Here is how it is looking running on my DIY electric lawnmower brushless controller:

As you can tell, its not perfect, but it works!