I trialled a number of these devices when they started to appear on the market about three years ago. At that time none of them started a cold GU ZD30. All of their promotional videos and such showed the device connected across the existing battery - so the battery was still assisting in the start. I disconnected the battery completely and used the device only (simulating a dead flat battery) and no - it would not start the diesel Patrol. The later high current ones did not have a problem starting a 4 cylinder petrol though.

I only mention this because if you are relying on this device to start your dead flat, cold diesel in the middle of no where - you may be disappointed. Try it as a stand alone first.