Voltage drop (who brings it to the trash can???)

Moin people, after we didn’t use our fat for a few days (sh.ss high fuel prices), was again the battery empty. Has happened already, after the car corso after the won, Germany game (high temperatures, and constantly running radiator fans and light and climate fully turned up…) I have now measured only 12.9 volts on the battery. Is everything not so bad yet, on the alternator are 13.8 volts on, very passable value, ergo, cable defective. Now my Fr number one: Does the cable go from the Lima directly to the battery, or does it take a detour over the starter? Question number two: Which idiot builds the Lima so close to the cracker that you burn your fingers when measuring????? I hope you can help me, I want to make the cable new now, so that my battery gets full again, and no one has to bring out the voltage drop.