Air conditioner fan switch

Prismtag

Should that be on or off in a 2022 tag while air conditioner is on.

Sharon_is_SAM

Whenever you use the A/C, turn on the fan. It brings in air via the vent bells on the sides of the trailer and the two inside vents near the sides of the A/C. It allows the A/C unit to take in cabin air and exhaust hot air under the TaG.

Prismtag

Thanks

Sharon_is_SAM

@Prismtag - you may want to do a forum search on air conditioning. While not ideal, there are ways to optimize the A/C including cracking the overhead vent and a window to promote air circulation.

Prismtag

Thanks, did that, the fan sounds kinda sick, imho? Not the air conditioner, the separate fan🤷🏻

The_Rigger

Out of curiosity, are the A/C exhaust fans 12v DC or 110v AC?

I have a current-sensing mod in mind...

JamesDow

The fan is on DC.

The_Rigger

@JamesDow said:
The fan is on DC.

Thanks. That complicates things a bit, maybe...

There are current-sensing devices used widely in woodworking shops that pair up a shop-vac with a miter saw or table saw, for sawdust collection; plug both tools into the device, and when it senses the saw motor drawing current it automatically powers up the vacuum.

My thought was to build such a device that would sense the current draw when you turn on the A/C and automatically power up the exhaust fan, primarily because I know I'm occasionally absent-minded enough to forget to turn the bloody fan on myself.

The catch, of course, is that most of the time the two devices in such a situation use the same input power, which apparently is not the case here. If both the A/C and the exhaust fan were on the shore power circuit, that would make life quite a bit easier...

GulfCoast

Wouldn't a typical relay with a 120V coil like what @The_Rigger described work to switch the DC circuit on? The switched contacts don't care whether the load being controlled is DC or AC.

The_Rigger

The switched contacts themselves don't care, but most of the time these switching devices use a single power source to feed both the current-sensing output and the controlled output. I certainly can design and build something with split input & output voltage, I was just hoping to keep it simple.

Hmm. I guess I could replace the DC-powered exhaust fan with an AC-powered one...

(Or I could just remember to turn the bloody thing on, but where's the fun in that?)

GulfCoast

Another benefit would be eliminating the possibility of unintentionally switching on the fans with your toes while sleeping.

Is there a packaged gadget that would sense AC current in the air conditioner circuit with a coil (not connected to AC) and switch a set of DC contacts?

(This sort of uninformed wishful thinking is about as far into solid state electronics as this mechanical engineer can go.)

The_Rigger

Such a packaged gadget is exactly what I'm looking for. Haven't found it yet, although I'm still searching. That's also why i'm starting to design one, in case it just flat-out doesn't currently (pardon the pun) exist.

GulfCoast

How about this?

https://www.amazon.com/CrocSee-Miniature-Normally-Monitoring-Detectable/dp/B086YT49H7

The_Rigger

https://teardrop-trailers.vanillacommunity.com/discussion/comment/12846#Comment_12846

Well, it might work but they do claim the secondary is not to be used for DC circuits...

GulfCoast

My initial reaction, too. But on reflection, convective airflow effects are insignificant compared to that big electric condenser fan in the air conditioner. Having the inlets at the cowbells and the discharge below the camper reduces the amount dust sucked into the system.

GulfCoast

@The_Rigger said:
Well, it might work but they do claim the secondary is not to be used for DC circuits...

Yes, I missed that in the fine print. But the first video review shows a fellow switching a 12V LED with it. I'm wondering if the AC-only information is a result of Chinese/English translation shortcomings.