It’s been hard to set aside time to write about this project, let alone work on it over the past months/weeks. Yet, in that same time some huge steps have been made. Last I posted I had dropped the motor in to the engine bay. I’ve now gotten various different parts and pieces ordered, as well as had my shipment of batteries arrive! Let’s dive in…
On the electronics front, I’ve made progress with the junction and contactor boxes. I’ve got everything for them save for the holes drilled and the 150V 400A fuse for the traction pack (why do large fuses have to be so expensive???) I developed a wiring chart in google docs so that I can flip to any of the various cables or terminal boards and know exactly what is linked to what. In addition, the wires are labeled, so that’s always helpful! The motor controller has a very short whip to the junction box where all the various other functions will run with separate wires. I just thought this to be the best way, as troubleshooting will be more straightforward for me. The other functions will include the throttle, transducer-variable regenerative braking, motor encoder and temperature sensor, as well as the contactor box and some dashboard switches/indications. Overall, awesome stuff going on!!
On the mechanical front, the brake cylinder and its associated hardware are mocked up and in the process of being welded together in steel. I’ve gone this route using a Tilton Engineering master cylinder because using the original cylinder would have precluded the positioning of the contactor box. This was no good, as the high voltage cable would have to be routed to different places, and the overall placement of the contactor box was nice in that top driver’s side corner. Once the pieces are welded together and installed though, then I’ve got to run some brake line and see if I can bleed the brakes. I’m also going to be installing a proportioning valve to restrict pressure to the back brakes. This is because the rear wheels will have regenerative braking on them from the traction motor, meanwhile the front wheels will only have the brakes. I don’t want my rear wheels to lock up, thus the proportioning. Hopefully I’ll be able to tune it right!
And as an aside, look at these batteries! I’ve got 6 tesla model-s modules. Everything looks good with them, good volts and mechanicals. It’s amazing to me how heavy they are! 55lbs a piece. It’s going to weigh the sprite down considerably. First things first though, I have to figure out how to protect them and secure them to the body of the sprite. That’s going to be no trivial job, but with determination I think I’ll make it through!
Thank you for sticking around for this ramble, my brain is scrambled sometimes but making progress on this project is exciting! I hope to be more focused in my next post, as I get things done.
Lombardi Engineering 