My Smart 451 mhd BJ 2007 doesn’t start anymore. After ignition, all the lights light up and turn off, ECO flashes briefly and then goes off. I try to start then, click it for a short time from the direction of the fuse box, but nothing happens at all. The gears can be switched on without a running motor. Does that sound like a flat battery? This is now 12! years running smoothly? Mhd is switched off every time directly after engine start. Do I have to install an AGM battery now or would a VARTA SILVER C30 12V54Ah 54 Ah for the requirement profile? The car is moving 23 kilometers in the morning and the same distance in the evening. Or is there a better suitable battery now? Many greetings