The blog for conversion of vintage BMW 3.0 CS coupes to Tesla powered electric vehicles
One CSE on the Road
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As I've mentioned before, my CSE project has taken a backseat to finishing the first CSE for my son-in-law. That car (I'll call it the Silver CSE from here on, versus my Blue CSE) was started by Paul Dexter and was the initial inspiration for my car. It was on the road as a full Tesla-powered EV, albeit in primer, for most of 2021. In late 2021 my son-in-law purchased the car from Paul with the promise of having me finish it.
Sizzle Reel - click to view
I tore it down, rebuilt all the brakes and suspension, installed cooling lines for the batteries, relocated the BMS, cleanup up the underside, rewired everything, installed air conditioning, sent it off for paint, finished and programmed all the fancy instrumentation, replaced all the rubber bits, replaced all the trim, fixed the sunroof, finished the interior, etc. and got it back on the road in August, 2022 for their wedding.
The underside of the Silver car with Tesla Model S large drive unit in the back
Installing battery box
Under the hood. 12 Tesla Model S batteries and a Tesla electric AC Compressor
But it wasn't fully sorted so it came back to my house for all the final sorting. It wasn't until June, 2023 that I finally delivered it. To celebrate we did a couple photoshoots and a Sizzle Reel. The photographer, Royce Rumsey, also did an article on the car for Exposures.
At the Lyons Air Museum, July 2023
Complete with custom CSE Owner's Handbook
It came out really nice. It is super fun to drive. The new owner loves it and that makes me happy. Now I need to get up the gumption to work on my own car....
As you probably know, I'm not converting just one BMW 3.0 CS coupe to Tesla power but two. One for me and one for my son-in-law, Alex. In fact, I'm involved in a third project for a customer as well. Brett Perkins at P3 Conversions is handling that build and I just consult a bit but I thought it would be interesting to compare how each project has tackled similar problems in different ways.
My priorities are all wrong. The car still needs a restoration and at the moment isn't even moving under its own power but I got side-tracked. In my defense, this all started over two years ago, when I had more momentum on the project. And it isn't uncommon for auto restoration projects to start with parts accumulation. Often they end before completion but I'm hoping that's not the case here. But I digress (again).
As mentioned previously, careless treatment of the Tesla battery modules can be catastrophic, leading to fire or other failure. Therefore, it is important to monitor the state of the cells to assure they are in proper temperature and charge or discharge. To do this, a Battery Management System (BMS) is required. I'm using the popular Orion BMS 2. The BMS protects and monitors a battery pack by monitoring several sensors and using several outputs to control charge and discharge into the battery. The BMS measures inputs from cell voltage taps, a hall effect current sensor, and thermistors. Using the programmed settings, the BMS then controls the flow of current into and out of the battery pack by broadcasting charge and discharge current limits via the CANBUS to the OnBoard Charger (OBC). During and immediately after charging, the BMS will balance the cells using internal shunt resistors based on the programmed settings.
