Hi Jonathan Battery is a Banner Starting Bull. I believe it’s a 530 34 although it’s difficult to tell as the markings have rubbed off. It’s a least 3yrs old as that is how long I’ve had the car. Yes, if I blip the throttle, the voltage rises and drops again. I wasn’t able to measure the crank voltage as the car starts instantly. The ignition warning light comes on when I turn ignition on and then disappears when the engine starts. It does however fade in when the engine is rev’d and fades away at idle. I don’t know whether this is coincidental but until this morning, the car has ‘juddered’ around 2.5k rpm which was fine when accelerating through 2.5k but a pain in traffic. Since I fully charged the battery last night, the car has driven very smoothly today. Thanks Tim