Before I write a lot I better get to my problem immediately:Important values: 1. Ford Puma with 70A alternator. Measured value with running engine 14,35V 2. “Motor off”: (car on the eve 9km driven with increased volume): Measurement in the morning afterwards 12,35V 3. Battery: slightly older, Berga Basic, 53Ah cold current test 470A 4. “+” battery up to power stage about 5meters long in cross section 35mm2 5. “-” 1x ground point rear seat & 1x ground point carouses each 10mm2 and both about 25cm long 6. Power Amplifier: Monacor 1/1000D 1200Rms (Gain at approx. 70%). Connected is an Esx Signum Sx 1222 2×2 Ohm Subwoofer with 750Rms in 1 Ohm operation Sonstieges: line alternator to the battery still unchanged & line battery to the ground point also original. I do not have sufficient power supply. The light as well as the incurrent lighting flicker strongly. The laid 35mm2 cable is copper cable class6 so pure copper. So the cause at this point I exclude. both mass cables from the trunk to the power stage are 10mm2 Ofc copper cables with which I used before only the one power stage for the front system. Now the question is, to which I have to go further to ensure a good power supply. I ask first of all for professional and above all usable recommendations. I am grateful for every advice. Oh yes, the second power stage for the front speakers I have briefly disconnected. The voltage drop remains unchanged (ESX SE 480) Thank you very much 🙂