To support a 5k amp you need more than a 250a. You know this. Why would you, or anybody, buy a 5K amp and not plan on using it? Just to say oyu have it? I never mentioned not using it. Realistically if your playing music, the impedance in the circuit will be varying all the time, so you won't be drawing the max current 24/7. Between his alternator and his battery reserve, he should not have an issue with voltage drop hurting anything. Sure he'll likely experience some slight voltage drop, but that doesn't mean his batteries will go dead, he'll get stuck on the side of the road, or his ecu will fry. There is a misconception that I as pointing out. Battery reserve has NOTHING to do with voltage drop when the vehicle is on and when you are trying to prevent it from happening. The alternator(s) supply the +14V. Batteries, for a 14V system, rest at +12V. Once the current demand exceeds the output capabilities of the alternator voltage will drop. Period, the end. No if and's or but's about it, 250a inst enough for a daily setup on a 5k amp (this does not even mention the vehicle's electrical demands or other amplifiers used in the system) And if it is than your 5K amp is.....wait for it.....overkill. Maybe for some people driving around at 12V is ok