I have a large 4V battery (1350Ah and 320lbs) that I would like to use as a standalone power source in my garage. I have seen some DC-DC converters for $10 that will allow me to run a ~35 watt load but I would like to be able to use more like 300-400 watts.
What would be the best way to do this? I understand that adding more batteries to get the voltage up to 12V would be the easiest but that isn't an option.
My obvious lack of understanding has lead me to believe that if a small converter is possible, then so is a larger one. 150A does sound like a lot, but it is less than what would be going through a common 2000W inverter (12VDC to 120VAC). Is the difference because I want ~150A from DC to DC vs DC to AC?