John61CT wrote:The latter.
These days a "converter" as used in the modern USA RV industry is really a charger, the ability to run without a House bank irrelevant.
In effect the battery just buffers the charger output, the bank SoC is not drawn down unless your loads' current exceeds the charger output.
My wife's 20ft travel trailer has a WFCO converter in it; it hasn't been used, except for emergencies since 2015, and is powered thru an outlet in a shed. Twice since 2015, the power tripped-off in the shed, and went unnoticed until after the "house battery" froze (with no power coming in, over a cold snap). Since the last time, I leave a 12v light on, that I can see from the back porch, so I know "if the power is on/battery is OK/converter is working".
Both times the converter stopped working entirely, until I replaced the 12v battery (exposed, on the tongue). One time, the converter board didn't respond, and I replaced it, too. This convertor needs a 12v battery to actually work at all; no 120vac is supplied if the 12vdc is removed. Maybe it's just that unit?