Have you checked the gauge (thickness) of the wire from the battery to the M2-ATX? The ticker the wire, the better; Also, heat plays a major role along with the compsumption (try to disconnect one of the drives, mainly the HDD) I have no doubt in my mind that this is the best DC-DC PSU because, yesterday, it was pouring here, and I forgot to lock the rear gate on my SUV and the PSU got wet. It was only powering the 5V rail. Took the unit out and dried it with a blow-drier, waited about 1 hour and VOILA! the unit was gain in tip-top shape!