cars newest problem.

[SCHWARTZ]

Car developed a new problem today took it for a bit of a blast and after about an hour battery light came on and it died
Couldnt see anything wrong but the car would not start, turned out one of the fuses for the volvo loom (by the 2 relays) had blown swapped it for a good one and car fired up.
Now every time i put my foot down the battery light comes on and the engine jolts also it wont rev over 2k without doing it. I nursed the car home and will take a look asap.
Something has caused the fuse to blow but what? could it be alternator related? Any tests or things to look for would help me out. cheers fellas

[Haz]

alternator diodes gone causing the charge to jump to 18v??