I had the battery not charging warning appear on the dash as I was driving back from work.

I kept on going as I knew it was not far home and the battery is huge( I did turn off the lights and heater fan)

Within a matter of minutes, a gear box error showed and it was stuck in third gear, then e diff error then the dash went totally blank. Not even the indicators would work.

I got home and even the stop start button would not work. I had to hold it for ages for the engine to stop.

I measure the battery volts and the battery was at 10.5 Volts

I charged the battery over night and it was at 12.8 volts. Started the car and it remained at 12v. No output from the alternator.

I checked there was 12v at the main alternator connection and that the voltage regulator had volts on it ( which it did at 7.5v)

Next I took off the alternator and found this.






The slip ring on the lower side of the armature had worn away and the brushes had done the same

Lucky I found a brand new Denso 1103 alternator in eBay for £99

Less than the cost of rebuilding the alternator

New alternator on and all back at 14 volts

The only hard part of the alternator change was the top bolt holding on the alternator. The belt for the supercharger gets in the way of using a rachet so it's painfully slow doing a quarter turn at a time and typically the bolt is 50mm longer than it needs to be so it takes ages.

 

Thanks for the pic's. How many miles are on the car. Was the failure caused by a bearing or just the brushes wearing out. As I understand it the 2010-2015 use a different alternator then the 2007-2009. Just trying to see if there is a problem with the newer unit. Also I started another thread on what type of pulley is on the front. Do you happen to know if it is a one way clutch type pulley or can you feel a spring tension in it if you rotate it in the opposite direction of rotation. Nice job by the way.

 

The car as done 63k miles. It's hard to tell what caused the fault.

I was shocked how the bottom slip ring had totally worn away since the brush is made of softer material than the copper slip ring. My guess is that the slip ring broke up and took the brush with it but it is only a guess.

I was hoping to just change the brushes but when I saw the slip ring , I knew it needed a new alternator.