Smart 451 completely functional after hibernation

Hello you love, I took my smart out of hibernation again and had to bridge it to start it. After I drove it out a bit, the battery was recharged again and then it was ok again. Unfortunately I had to find out weeks later that it now doesn’t start at all. Even he doesn’t want to unlock himself. Complete electronics is dead. So I went here and bridged it over. When I connect it, everything started again immediately. But as soon as I turn it off again after the ride, it is completely dead again. I went here and bought a new battery. It also fits. After the exchange, the problem persists. I have niergens current on it. Do you have any tips? Is a Smart Fortwo MHD dear greetings