12 volt regulator for Maxx Fan

Hey guys I had a question since I’m only able to run to my Maxx air fan at 20% speed and anything higher makes it shut off and beep. We did get a new circuit board installed and that didn’t fix it. I also put a new battery in and that didn’t work either. My next step is to put a 12 volt regulator in by the fan to make sure it maintains 12 volts should I do the 12 volt 5 amp or 12 volt 3 amp one ? I’ve been reading different forums and watching YouTube videos and I’ve seen this fix with a regulator