Looking for some feedback from those better versed than I in battery behavior. My custom camper's 12v power system relies on two Deka 4d agm batteries with a combined 420ah of storage. Cabin heating and cooking duties are handled by a Wallus 85DU diesel cooktop and herein lies my question. The 4-5 minute start up cycle of the Wallus draws 8 amps which, when the battery bank is fully charged (12.97v) draws the voltage down to 12.33. Once the start up cycle is completed the battery will gradually return to near "resting" voltage. Maybe I'm a bit paranoid but even after 3 years of using this system I still wonder if that amount of voltage drop is normal? I realize that the Wallus is a marine product and assumes an alternator will probably be supplying consistent voltage during start up but still, considering the size of the battery bank, should the voltage drop that much under an 8 amp draw? I've chatted with the folks from both Wallus and Deka but have yet to receive a reassuring answer. Thoughts?