The car is being converted as a body-off restoration project, and the entire electrical conversion should live in the frame/chassis. It’s not quite a skateboard-type chassis like most modern electric cars are approaching car-design, but it should be a self-contained chassis with all of the batteries, motors and drives in it. The whole conversion consists of

• The high-voltage / drive-power section of batteries, cabling, fuses and monitoring
• The low-voltage / accessory-power section incl DC/DC converter
• The controls and instrumentation section incl PLC

Where each detail fits in these descriptions is always up for debate. The PLC controls (most of) the car’s accessories, those in turn run on 12V/low-voltage and some even monitor the high-voltage part. I’ve tried to split things in a way that makes sense, and I’ll keep shuffling until I find a better way.

High-voltage / drive-power

The high-voltage/drive-power section of the conversion consists of 3 battery packs (to distribute the weight and to use the under-hood and under-trunk spaces) with their 4|0 cables and a switch box that holds the general disable switch and the main fuses. The primary method of monitoring the state of the high-voltage battery is through a custom adapter that sits inside the trunk underneath the package shelf and connects to the PLC. There is a secondary way through the PLC to the CAN-bus interfaces to the Siemens motor-controllers. I use that path to make sure the motors are balanced around torque/power and not over-driven, but I do not calculate state-of-charge from there.

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Low-voltage & accessories

The low-voltage & accessory section of the conversion is where a lot of the unseen work goes. The high-voltage side has impressive bits like motors and batteries etc, and it’s what comes to mind when you say you’re converting a car to all-electric. The low-voltage circuitry that is needed to then make it all work can be very rudimentary (a glorified go-kart), or it can be much more complicated than the high-voltage bits (a nicely decked out “modern” car). It all depends on how involved you want to get in keeping the original look & feel, adding features, and what the car had to begin with. This car was the luxury car of its day, it had every feature people could think of, and keeping with that idea has meant a lot of work to make it all look 50’s but work 21st century.

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Controls & instrumentation

This part goes into the methods used to collect all of the run-time parameters that are needed to figure out whether it’s a car or a projectile on fire. This is where flow & temperature sensors, voltage and current data etc are collected and processed into the PLC (the central brain of the conversion) as well as how that PLC then communicates with the Siemens motor-drives over CAN-bus. It’s as much of a lab notebook section as it is meant to be informational, but it has to go somewhere.

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Charging

The charging part of the conversion remains a mystery at this point (summer 2024). I have a battery, it’s not a ridiculous battery, and I just simply haven’t figured out how to connect it to The Grid. It can wait. For now I have too much to do already to get the whole thing wired and connected up etc, and the charging part is a piece that stands completely alone so I’ll figure it out later….