30-12-13, 06:18 PM
Fuses: people often think they are there to protect the bit of equipment that they are attached to. In fact, the fuse is also to protect the cable. If the supply wire gets chafed and starts shorting to ground you're relying on the fuse to cut the power before the wire gets red hot and sets things alight. The length of wire between the battery and fuse is not protected so you want it to be as short (and well-insulated) as possible.
Yes, I'd ignore that 11.5v reading.
Another measurement I'd try is to take a look at the battery voltage with the engine not running and then turn on the headlights. If the voltage plummets in a few minutes to 12v or less then it is knackered regardless of what your dealer told you. (Five minutes powering both headlight bulbs should use about 10% of a fresh, fully-charged battery's capacity.)