This thread makes me laugh. Lakota is a so called EE student who doesn't understand the concept of fault currents. Once the amp is drawing more current than the charger can provide the voltage on the charger will drop to the voltage of the batteries, the batteries will then also drop and the charger voltage will drop with it. Study a power system. If on a 12kv electrical line you get a direct fault the line will not sit at 120v RMS, it will drop down while delivering 10KA of fault current, this is the exact same situation as the battery charger experiences.
Basically the charger will act as a constant voltage source until the current draw exceeds what it can put out, then it will become a constant current source with the voltage dropping according to ohm's law.