[JRTJH]

There is a warning sticker on most RV slide control panels that says, "WARNING, do not operate slide switch unless a battery is installed". (or words similar to those).

The reason to have a battery installed in the 12 VDC system (per the warning sticker) is to prevent an excessive load on the converter when using "large demand electrical systems" (slide motors, leveling systems, landing gear).

If the battery is "dead" or "significantly discharged" it is putting a "demand on the converter" to recharge it. Adding additional loads to the output of the converter would only increase the potential to overload the converter. Since installing the battery in the circuit is done to decrease the potential to overload, I'd think that having a "dead or discharged battery" in the system would be increasing the potential for excessive load and could result in damage to the converter.