Box under the bed that hums?

[skiptut]

When plugged into home shore power (haven't been on the road yet) I have a box in the storage box under the bed on my 29M Windsport. It hums for awhile then shuts off, back and forth. Is this part of the battery charging system?

[Beau388]

Probably the inverter. The converter hums constantly; admittedly at a very low volume. Both units have fans. The inverters fan is controlled by a thermostat and has several speeds. The fan will run even though it is off. The converter's fan is amperage controlled. The fan seems to run when there is no reason for it to power up.

[TurnerFam]

Do you HAVE an inverter?

or do you actually have a CONVERTER?

many rvs without residential 120v fridges will only have the converter, which does have it's own fan(s) to cool it down when you are plugged into shore power and it is converting 120v down to 12v for the rv. My father's converter in his fifth-wheel makes a humming noise, and is located under the kitchen cabinet.

if you have an inverter, it also has fan(s) that cool it down, but mostly when it is 'working' when you are NOT plugged into shore power. Sometimes they can continue, though, even after you've been parked for a while on shore power.
My inverter bay, under my bedroom window, also has another external fan to help cool the inverter, which can be annoying since it seems to run way too long after we've stopped, parked for a while, and are plugged into shore power.

Another thing could be your ATS, or automatic transfer switch, since your motorhome likely has a generator. The ATS provides for safely transferring power to your breaker panel from whichever power source you have access to: either generator or shore power. Since it 'defaults' to generator power, it will make a 'humming' noise when on shore power, since it's magnetic switch is always 'on' in order to keep you connected.
Ours is under the foot of our bed.

[SuperD]

Originally Posted by skiptut

When plugged into home shore power (haven't been on the road yet) I have a box in the storage box under the bed on my 29M Windsport. It hums for awhile then shuts off, back and forth. Is this part of the battery charging system?

Ours does the same thing, normal and don’t even hear it anymore.

If you slide the mattress down and toward the back of the coach you’ll see a panel with several screws at the foot of the bed towards the front of the coach, all the electrical is under that panel. It would be a good idea to remove the panel and check all the connections, especially on the transfer switch, several members have found loose connections. Before doing this MAKE SURE YOUR COACH IS NOT PLUGGED IN AND THE GENERATOR IS OFF!!!

[Beau388]

Originally Posted by TurnerFam

Do you HAVE an inverter? or do you actually have a CONVERTER

All Thor MCs with an outside kitchen have an inverter to power the outside frig even though they have an RV frig inside (propane/120 V).