Fabricating a battery box to accommodate 4 Chevy Bolt battery modules (~24kWh) where the engine used to be is not a trivial job, but a necessary one. I decided to put all 4 batteries up front instead of 2 in the front and 2 in the trunk for the following reasons:
Wiring simplicity
Better airflow/cooling capabilities
Closer to original weight distribution
Preserves original trunk space (The gas tank area in the trunk that could have housed 2 batteries will house 2 chargers and 2 DC-DC converters.)
Single drop in “module” for ease of installation/maintenance.
CAD Mockup
The base fabrication starts out with 1-1/4″ steel angle that I’ve cut and welded to form the bottom frame of the box. Aluminum panels will be fastened to the sides of the framing to form the box. There’s also a “subframe” that I’ve made using 1″ square steel tubing and 2×2″ angle. This subframe will support all 4 batteries, and will be riveted into the XJ-S’s frame.
Before weldingAfter welding: Bottom FrameSubframe MockupSubframe and bottom frame mockupAfter welding: Top Frame
A BMS is a required component of any lithium battery installation. The BMS monitors the individual cell voltages and prevents any cell from entering a dangerous over-voltage or under-voltage state. It also balances the pack (brings the cell voltages closer together) which can increase capacity.
We’ll be using Thunderstruck’s Dilithium BMS. The main BMS Controller supports up to 24 cells, and can be connected to up to 3 expansion (satellite) modules, each supporting an additional 24 cells, for a maximum cell capacity of 96. In the XJ-S we’ll be using 40 Chevy Bolt Cells (4x 10s modules), so we only need 1 BMS Controller and 1 BMS Satellite
Mounting the Hyper 9 Motor to the T56 Transmission was supposed to be a walk in the park. Unfortunately the adapter I ordered from CanEV refused to go onto the shaft of the Hyper 9. I sent the hub back to CanEV for them to bore it out a bit and fix some damage I caused while trying to beat it onto the motor.
Once I got the hub back and mounted on the Hyper 9, I discovered that the flywheel bolt spacing didn’t line up. Apparently the Chevy Small Block pattern that CanEV uses is slightly different from the LS3’s bolt pattern. In any case, I had to slightly grind 4 out of the 6 holes, and enlarge the other two. It remains to be seen if this will affect the balance of the flywheel, but as it’s pretty close to the center of rotation, I’m less concerned.
Adapter plate and hub bolted to Hyper 9After some “modifications”Mis-aligned bolt holes.
I’ve also been working on a front transmission/motor mount, which is coming along nicely.
Close, but no cigar.
After assembling everything and getting it 99% installed, I discovered that the T56’s input shaft was hitting the shaft of the Hyper 9. The only two options to fix this are to either drill out about 1/2″ of the center of the Hyper 9 shaft, or cut down the tip of the T56’s input shaft. I’m going to go with the former, as modifying a T56 Magnum isn’t something I’m keen on doing.
Leaf: They’re affordable ($50/ea), have fairly good energy density (64Ah per module when new, probably around 40-50Ah used), and due to the exposed terminals as well as the 5/16″ mounting holes, are easily re-arranged to suit any voltage/amperage requirements. If you have a larger budget and care more about range (higher Ah capacity), used 2nd Gen Nissan Leaf Modules are also available, at a 25% price premium over 1st Gen.
LG Chem (Chevy Bolt): The modules are much larger and heaver (about 10x) than a single leaf module, but they’re much more energy dense. They can’t be broken up into smaller modules, so you have to make room for the 72 pound 19″ x 14″ x 4″ modules. On the upside, you won’t have to make custom bus bars, and the BMS wiring will be easier if you can source a Chevy Bolt BMS harness.
More battery building coming soon! Example Leaf packs below:
One of the main objectives in this conversion was keeping the front engine, rear wheel drive configuration, without modifying the Jaguar Independent Rear Suspension.
Update: I’ve had a significant amount of trouble with the CanEV hub adapter for the Hyper 9. Initially it was too small to fit onto the Hyper 9, and now that it’s finally on, the flywheel bolt spacing isn’t correct, with two holes not lining up.
CanEV adapter on the XJ-S’s Chevy T56 transmission.Misaligned flywheel bolt holes. (Two bottom left)
Converting a classic doesn’t have to mean you can’t have modern touches. I made a vehicle status app using Blynk and a Particle Electron. The data is mocked for now, but it’s going from the Electron to the cloud to the app.
One of the objectives in converting the XJ-S is to maintain the stock interior; this means no digital gauges or EV displays anywhere.
On the downside, this means building circuits to make the tachometer work, the temperature gauge work, the oil pressure gauge display miles remaining, and the fuel gauge display battery SoC. (There will be a whole article dedicated to this later, but it will involve a Particle Electron, a lot of circuit design, and coding.)
In addition to the gauges, I wanted to have at least two switches to enable no/low/high regen, but I wanted them to look factory.
I decided to repurpose the non-functional “Heated Windows” switch, and the “Map Light” switch as low/high regen switches, however I could never leave them as they were…
I disassembled the switch and discovered that it’s a semi-transparent insert that has the writing on it. Some quick Googling, and I found a small print shop that would do transparency printing with a white base layer.
After re-creating the switch insert design in Adobe Illustrator, it was off to the printers!
The end result, a sheet full of various options, and a “Regen Low” insert installed in the factory switch.How close I got to the factory inserts.The finished product!
When converting a car to electric, sometimes the little details like power steering and vacuum boosted brakes get overlooked. Here we’ll explore some solutions for keeping those systems working.
Vacuum Boosted Brakes
Summit Racing® Electric Vacuum Pump SUM-760152
There are plenty of 12v vacuum pumps on the market, but not all of them are designed to provide enough hg for brakes (they’re intended for misc controls like HVAC or motorized headlights) or require separate sensors/switches to prevent them from running continuously and burning out.
My search for a self regulating pump that was suitable for brakes resulted in this: Summit Racing Vacuum Pump. This pump is designed for brakes and is self regulating; activating and increasing brake vacuum to 20 hg whenever the vacuum level drops below 15 hg. Note: You should still use a vacuum canister to reduce the duty cycle of the pump.
Electric Power Steering
Mechanical Electric Power Steering
Oh boy, how far down the rabbit hole of electric power steering do you want to go?
There are some mechanical solutions like EVWest’s Kit. However, these systems involve cutting and welding your steering column and installing a controller that’s basically just a potentiometer that you have to install somewhere reachable to adjust the level of assist. (I greatly admire EVWest, but it’s a gross solution.)
Since I wanted to maintain the factory Jaguar rack/column and steering feel, I decided electro hydraulic was the only way to go. Unfortunately there really aren’t any aftermarket solutions for this, and unless you know what you’re looking for, good luck finding a compatible pump.
Bosch Automotive KS01000120 Remanufactured Electro Hydraulic Power Steering Pump (EHPS) for Mini Cooper
My requirements:
12v powered
Self regulating (no controller or canbus required)
Readily available
Not outrageously expensive
This list seems simple, but there are almost no electric pumps that meet all of those requirements, except one, the Bosch OEM Mini Cooper Pump. The only connections are 12v and the hydraulic lines! Note: This pump runs hot and requires significant air flow to prevent overheating.
