Defender 110 EV – A 100 kWh Tesla-Powered Daily Driver

This Defender 110 EV conversion is one of our most complete engineering projects to date. Powered by a full Tesla 100 kWh battery pack split across 10 front and 6 rear modules, it combines range, power, and reliability in a way few classic conversions achieve. We engineered a dual A/C cooling system with two 34 cc Benling compressors and Golf Mk7 condensers to keep both the cabin and batteries cool, even under tough conditions. A custom VASS controller ties everything together for seamless operation. Inside, the original Puma gauges were reverse-engineered to display correct gear positions, battery temperatures, and mileage, while a Range Rover Velar drive selector and integrated electric parking brake deliver modern usability with OEM quality. Add upgraded differentials and half shafts, and you have a Defender that’s not just electric — it’s engineered to be driven every day.

Dmitrijs G.

9/2/20253 min read

At VASS, every Defender project teaches us something new. Our most recent Defender 110 EV conversion is perhaps the most complete demonstration of how far engineering can go to transform a classic into a modern, daily-drivable vehicle.

This project features a full Tesla 100 kWh battery pack, carefully integrated with our own controllers, custom-designed HVAC and cooling solutions, drivetrain upgrades, and OEM-style user experience. The result is a Defender that doesn’t just drive electrically — it drives intuitively, reliably, and with the refinement you’d expect from a premium modern car.

Why Tesla Batteries?

During a trip to the UAE, one thing stood out: 90% of EVs on the road were Teslas. That reliability and ubiquity made our choice clear. We opted for a Tesla 100 kWh pack, configured with 10 modules in the front and 6 in the rear.

Tesla modules are well regarded for their efficient liquid cooling, but even they face heat build-up from external factors like reflected road heat. That’s why we designed this Defender’s pack with active cooling built in from day one.

Cooling Strategy – Dual A/C Systems

One of the first challenges was deciding whether to use a single pump or a dual setup. In the end, for both simplicity and capacity, we chose two 34cc Benling A/C compressors.

To match them, we sourced the largest condensers we could find: Golf Mk7 units, which conveniently integrate the dryer directly into the condenser. This simplified packaging and maintenance. Custom adapters were required, so we designed them in 3D, resin printed test pieces to confirm fit, and then had the adapters manufactured. They worked flawlessly.

A custom VASS controller manages both systems, intelligently responding to thermal load and ensuring reliable operation even under extreme conditions.

Charging & Thermal Load

This Defender was not specified with CCS, simplifying thermal management. Instead, it uses three TC chargers (6.6 kW each) for a total of 19.8 kW AC charging. At this rate, the pack warms up slowly, if at all, during charging, making the thermal system’s job easier.

Drivetrain Upgrades

Power is nothing without control. This Defender received:

Limited-slip differentials at every diff, including inside the Tesla motor.
Upgraded half shafts.
CNC-machined end caps.

Together, these upgrades reduce drivetrain backlash and improve overall driving feel, making the vehicle smoother and more predictable.

Controls & Interior Integration

One of our goals was to deliver a modern OEM experience, not a dashboard covered in switches.

HVAC Integration: We retained the original Defender HVAC controls, adding potentiometers and switches where necessary. Our controller reads them natively, so the cabin functions as expected.
Custom Drive Selector: We fitted a Range Rover Velar selector, which communicates over CAN bus. Our controller interprets its messages and communicates with the rest of the car over a second CAN line. Safety was critical — the selector is locked out during charging, preventing the car from driving away.
Parking Brake Integration: The Velar selector also controls a Wilwood electric parking brake. Shift into Park, and the brake applies automatically, with the handbrake light illuminating on the Defender’s dash just as it would have from factory.

We’re now working to develop this selector system into a standalone product, allowing other converters to benefit from the same superior feel and safety.

Reverse-Engineering the Puma Gauges

Most conversions rely on a black box to spoof CAN signals to the Puma cluster. At VASS, we took it further. We completely reverse-engineered the cluster, controlling:

Needles (speed, RPM, etc.).
LED indicators (turn signals, handbrake, headlights, etc.).
The LCD screen — including gear displays (P, R, N, D, S).

We also integrated:

Mileage tracking, stored in secure FRAM and calculated from motor RPM.
Temperature readouts for motor and batteries.
Safety warnings, just like the OEM system.

The result is a Defender that feels authentic but fully modern.

An Intuitive Driving Experience

By tightly integrating all systems, we created a Defender that is intuitive to use:

No need for multiple toggle switches.
Safety and usability designed in from the start.
Luxury touches (Velar selector, seamless gauge integration).
Rugged drivetrain upgrades for daily confidence.

This build is more than an EV conversion — it’s a complete re-engineering exercise. It takes the Defender’s heritage and elevates it to a modern daily driver standard, without sacrificing its soul.

👉 This project proves what VASS is all about: combining engineering precision with real-world usability. It’s not just an EV Defender — it’s the most pleasurable Defender you can drive every day.