Hello, it all started with the fact that when the ignition started, everything was running out of power (small display & displays) and then the engine started. (Video: https://youtu.be/srEbVwmn0tc ) About 1 week later, the Harley only started at the second start. (Temperature approx. 10-15 ?) (Video: https://youtu.be/ycONANPPQcA ) At the first start you heard / noticed that the engine started but stopped. At the second start it happens again but the engine starts properly. About 2-3 weeks later the engine didn’t start at all and there were only dull noises (I thought… ok battery flatt)New battery: (Motobatt MBYZ16H) I installed it directly and did not charge it (because it says on the package “No initial charge required”).The engine started directly (I didn’t notice anything) and started driving. At about 4 – 5 start (motor bike was not long) it started just like with the old battery. So everything that consumes electricity briefly but the engine started the next day (charged overnight) only at the second start. I measured the voltage and the voltage breaks down from 12.7V to approx.5V – 6V at the first start. At the second start immediately afterwards it drops to approx.8.1V and the engine runs.Did I just have bad luck, with the new battery or do you think it might be something else?The charging voltage is 13.9V (without giving gas, cold start = approx.1350 revolutions) Greeting Finn Forty Eight from 2014 with about 7000km