srailsback
We're new at this. We just got back from dry camping. I plugged in the camper to charge up the battery. Hearing a fan noise behind the fuse box. Haven't heard this noise previously. Reading online (other brands) suggests its the cooling fan for the inverter -- this correct? Nothing to be concerned? 
Quote 0
fireblot
If your camper is factory stock, you do not have an inverter, but you do have a battery charger that is located in the space behind the circuit breaker panel. That is most likely what you are hearing. My charger (Retro model 181b) is visible from the cabinet under my sink..... your’s may be also. 

Welcome to the forum! What model do you have? Don’t be shy about sharing pictures of your trips!
Quote 0
Tom
Yes, it's the rectifier.  AC to DC: rectifier.  DC to AC: inverter. 
When your rectifier is working hard (charging battery, all lights on, etc.),
it runs a cooling fan, or, at least mine does.  2014 155 original drop floor.  
Quote 0
sunvalleyjoe
normal cooling fan my runs even at home on shore power nothing to b alarmed about.GBA!!SVJ
Quote 0
mikes
They're called converters, they're basically DC power supplies, but most do some form of staged battery charging. An inverter converts (!, but a converter doesn't invert, go figure) DC to AC. A rectifier converts AC to really poor DC, but doesn't change or regulate the voltage (it would be really bad to try and charge a 12 VDC battery with rectified 120 VAC). Although, in the old-school telephone (PBX) industry, they do call battery chargers/power supplies "rectifiers." So, much depends on the context. We're talking about RVs here.

The fan comes on when they're providing more than (some amount) of power, to keep it cool. The fan shuts off when there's a low load.
Mike
Quote 0
Tom
"Converters", well thats a new one for me.  Terminology counts.  I learned mine in electronics. Couple of diodes, or the right vacuum tube, and a few capacitors and I can "rectify" 120 ac into the nicest dc you can find short of a battery. All good. 🙂
Quote 0