How To Install 12v Vent Fan In An Enclosed Trailer With A 120v Panel

Updated 05/06/2026 | Published 05/04/2026

Products Featured in This Question

Progressive Dynamics 9300 Series RV Converter Charger - 12V - 30A

(328)

$226.87

MaxxFan Deluxe Roof Vent w/ 12V Fan, Thermostat, and Remote - Powered Lift - 10 Speed - Smoke

(1449)

$475.35

Question:

I have a 120v panel in my enclosed trailer and want to run this fan. Is there a best practiced or recommended method to wire for best results? Being it is 12v/5amp I assume I need a transformer step down the power. Any insight would be greatly appreciated.

asked by: Luke K

Expert Reply:

Hey Luke, thanks for reaching out. You’re on the right track, that MaxxAir fan is a 12V unit, so it won’t run directly off your 120V panel. What you need is a 12V DC power supply (converter) to step that 120V down and give you a clean 12V output the fan can use. For a fan that draws around 5 amps, I’d go with something in the lower amp range so you’ve got a little headroom and it’s not working at its limit all the time. What I recommend is the following:

- Progressive Dynamics 9300 Series RV Converter Charger - 12V - 30A # PD49RR

From there it’s pretty straightforward. You’d feed the power supply from a breaker in your 120V panel, then run 12V wiring from the output side of that converter to the fan. Treat that 12V side like any low-voltage circuit, use decent gauge wire for the run and add an inline fuse close to the power supply to protect the circuit. If you ever think you might add more 12V stuff later, it’s worth going with a slightly larger converter now and maybe even a small fuse block, but for just the fan, a simple converter-to-fan setup works great and keeps it clean.

What kind of trailer do you have? Do you think you'll add any other 12v appliances?

expert reply by: Jesse M

Progressive Dynamics 9300 Series RV Converter Charger - 12V - 30A
(click to enlarge)

Luke K.

5/5/2026

Its an ATC trailer I use for motorcycle trackdays. No other 12v requirements, I already have a low voltage LED light installed. So this converter plugs in to an outlet then the 12v outlet would go to the fan?

Jesse M.

5/5/2026

@LukeK Nice! Yes the converter plugs into a 120 wall outlet and allows you to power 12v appliances like your vent fan.

Luke

5/5/2026

@JesseM any chance at a discount$$ I have spent some money now lol.

Jesse M.

5/5/2026

@Luke Hey it never hurts to ask but I don't have any additional discounts I can offer. Looks like it's already on sale though...

Bill

5/6/2026

@LukeK I purchased the Progressive Dynamics 30 amp charger/converter for my travel trailer from etrailer last June. I am pleased with its performance. It actually puts out its advertised 30 amp power. I checked it using two different sources. When I got it I had a couple of questions about how it behaved etc, and I called Progressive Dynamics and talked to a knowledgeable friendly guy for a good half hour. So customer support is definitely available. The only thing that’s rattling around in my head about what you want to do is the following: I believe you want to simply have 12 volt power supply to run a 60 watt, or 5 amp fan. But I didn’t hear you mention that you have a battery to work in conjunction with the inverter charger. I thought I heard or read somewhere that it is best to have the inverter/charger hooked up to a battery to act as buffer or reserve supply of power during quick drain start ups etc. I’m others words it’s best for the inverter to be connected to a battery. If you don’t already have a battery on your trailer you could get one and then you’d be all set when shore power isn’t available. Or perhaps a small power station that would cost less than the 30 amp inverter charger might be a better choice. In any case, I can absolutely say that my inverter has been working for me since last July

See All (4) Replies to Luke K. ∨