I am trying to run this voltage changer with a Patona Platinum 12V 12Ah battery. When I start the inverter, the red light comes on briefly, then gets quieter and quieter and then the voltage changer stops completely. So I can't start it. If I have connected the battery to the charger at the same time, the voltage changer starts without any problems. And the operation also works without the charger. But then I can't disconnect the voltage changer, because it can't be switched on again without the charger. Can anyone explain this problem?