Routing of power-cables and hoses
There are a lot of cables and hoses to make this car run. There’s the wiring setup between the battery packs, then getting that power through the central switchbox and out to the controllers, then back to the motors. There’s also the hoses for the power-steering and for the two cooling circuits. And somehow, all of these cables and hoses come together at and/or need to pass through the front support frame. The controllers sit in front of the frame, the batteries and motors are behind the frame. The radiator and pumps are in front of the frame, and have to connect to the same batteries and motors. It is one crowded setup.
For the connections from the engine-bay (motors & controllers) to the trunk (controls, charger & second battery pack) I am following the path of the original exhausts
I have routed the 4-0 power cables on the passenger side of the chassis, and the coolant hoses for the rear battery pack are on the driver’s side. With the power-steering gearbox where it is, the unwieldy power cables were just easier to install on that side. There’s also one extra hole in the frame on the passenger side so I was able to make a much nicer suspension-bracket for the power-cables right where they need to make some serious bends & turns.
Water-cooling
The motors, the controllers and the Tesla batteries all have water-cooling capabilities/needs. I’m not sure how much cooling the batteries need, it should be minimal, but the Siemens parts both for sure need a functioning cooling setup. I have set everything up as 2 separate cooling flows. Each flow has a pump, then a controller, then a motor, then either the front or the rear battery pack, and back to the pump via a small radiator.
The primary motor is the one that connects to the drive-shaft. Its coolant-circuit connects the driver-side motor controller, the front battery pack(s), the lower half of the radiator and the driver-side sensors & water-pump. The secondary motor is the one that connects into the other motor. Its coolant circuit connects the passenger-side motor-controller, the rear battery pack, the upper half of the radiator and the passenger-side sensors & water-pump. The two radiator fans blow on both radiators at the same time so those are considered 1 big fan for the sake of the control-logic etc. If I ever have to start heating the batteries I’ll consider turning them into separate units, but I think the effect would be negligible and the effort would be major.
Or, slightly more diagram-style
My radiator sizing math goes something like this. The original engine made 350 bhp, and 40% of that was heat/waste. The thing really was not super-efficient. That’s 150 bhp in waste energy (at peak power), and it had a radiator of app. 25″x35″ = 875 square inches to get rid of that in the worst of driving conditions.
In the electric version, I have around 250 bhp of power (peak) and my efficiency is 96% on the controllers, 98% on the motors, and 99% on the batteries. That’s 5-or-so percent of waste-power which is < 13bhp, or about 1/10th of the original. My optimism then lets me jump to the conclusion that I would need 1/10th of the original radiator size to accommodate 1/10th of the heat / energy, so something at maybe 88 sq.in. should be sufficient.
What I’ve designed is a dual-core radiator with two cores at 21″ x 3″ each, that comes to 126 sq.in. total so the unit is a little over-dimensioned. This is a 3-row radiator, it is kind-of “thick”, and per the square inches I could probably skinny it down to a 2-row radiator. However, I am trying to stay with a minimum flow/channel dimension of 1.5 sq in (to guarantee enough flow etc), and for that and because this is all based on optimism-engineering I’ve decided to stay with 3 rows, just in case. Maybe I’ll be able to run the fan slower. In the end, it looks more or less like this:
It’s actually 2 radiators/cores right above each other, the flow is L>R on top and R>L on the bottom, and they each have an inlet on the back and an outlet on the front.
That unit sits inside a shroud, and the shroud holds the two radiator-fans, the module with the flow & temp sensors, and then the axial water-pumps on their respective brackets. It’s supposed to look like
The whole assembly bolts onto the bottom rectangle of the front carrier-frame, and the setup looks like
Now all I have to do is get this made. The quotes so far are very impressive so I’m still shopping this, but the design should be done enough…