Mini Split Airflow Question

[Chronobomb]

I installed a mini split in my RV and have been very happy with it. I installed the outside part in my generator bay and it has been keeping the RV comfortable all winter and my power bill has dropped significantly. Now that it's heating up, the outside unit is getting ice. I had an AC guy come service it, but he said the issue is airflow in the bay. He recommended installing 2 6'" PC fans on the intake I cut below the unit.

Would it be better to run them off the batteries in the generator bay or off the 120v line I have running into the outside AC unit? Also is there any way to wire it so they come on when the outside unit is running? I thought about running a switch I could flip on, but I don't want to have something I will be forgetting to turn on or off if I can avoid it.

Anyone have a similar experience to mine or offer advice, I would appreciate it.

[traveldawg]

I'd suggest 120V since you would be running the unit on 120v anyway. And I'd try to find a way for them to come on when the outside unit comes on (which might be a lot as mine (for my garage at home) runs at low speed almost continuously when it is hot.

Maybe check to see if there is a DC voltage that runs the fan in the outside unit and match the intake fan(s) to that voltage.

I'd guess you would also need a means for air to exit that front compartments too to keep the air circulating. And then there is the issue of keeping water out from all openings when traveling in the rain.

[Chronobomb]

I'd suggest 120V since you would be running the unit on 120v anyway. And I'd try to find a way for them to come on when the outside unit comes on (which might be a lot as mine (for my garage at home) runs at low speed almost continuously when it is hot.

Maybe check to see if there is a DC voltage that runs the fan in the outside unit and match the intake fan(s) to that voltage.

I'd guess you would also need a means for air to exit that front compartments too to keep the air circulating. And then there is the issue of keeping water out from all openings when traveling in the rain.

I made a temporary door out of wood with a vent across the front to see if it will work before I order a replacement door from GD. I'll keep my old door just in case.

The vent is as large as the AC unit and backed with metal mesh to keep bugs out. Fortunately the bay is under the 5th wheel overhang so it stays dry when parked. I plan to make a leather or plastic cover to magnetically seal to the vent during travel with some turn button locks so it doesn't slide off.

I like your idea about the 12v power to the main fan, but sadly I can't take the cover off in the generator bay as it slides up and over. Too late for me!

[Jims94vmx]

I made a temporary door out of wood with a vent across the front to see if it will work before I order a replacement door from GD. I'll keep my old door just in case.

The vent is as large as the AC unit and backed with metal mesh to keep bugs out. Fortunately the bay is under the 5th wheel overhang so it stays dry when parked. I plan to make a leather or plastic cover to magnetically seal to the vent during travel with some turn button locks so it doesn't slide off.

I like your idea about the 12v power to the main fan, but sadly I can't take the cover off in the generator bay as it slides up and over. Too late for me!

While I don't have a solution, I would love to see pics and info on what you are running.

[traveldawg]

I made a temporary door out of wood with a vent across the front to see if it will work before I order a replacement door from GD. I'll keep my old door just in case.

The vent is as large as the AC unit and backed with metal mesh to keep bugs out. Fortunately the bay is under the 5th wheel overhang so it stays dry when parked. I plan to make a leather or plastic cover to magnetically seal to the vent during travel with some turn button locks so it doesn't slide off.

I like your idea about the 12v power to the main fan, but sadly I can't take the cover off in the generator bay as it slides up and over. Too late for me!

Maybe another idea for the front vent is put it behind the existing swing-down door. Maybe some sort of louver type vent with screen to keep critters out. That way you can close the original door and have a water tight seal. I don't think the AC unit would care about water, but the inside of the bay might not like it.

[Chronobomb]

While I don't have a solution, I would love to see pics and info on what you are running.

I am just running a 1 ton 120v Senville Mini-split I bought off Amazon.

[Chronobomb]

Maybe another idea for the front vent is put it behind the existing swing-down door. Maybe some sort of louver type vent with screen to keep critters out. That way you can close the original door and have a water tight seal. I don't think the AC unit would care about water, but the inside of the bay might not like it.

I spoke to an AC guy about different types of vents. I also wanted something I could close off instead of using a cover. He told me that the only vent that wouldn't cause my outdoor unit airflow issues was a grid, or honeycomb style vent. Anything else would cause airflow issues and icing.

[Jims94vmx]

Any thought on cutting the bottom/floor area to let it pull air?

[Chronobomb]

Any thought on cutting the bottom/floor area to let it pull air?

I cut a vent below the unit. That's where I want to install the PC fans, if anyone has a good setup their using?

[edontheroad]

I would consider running a low voltage wire from your thermostat to a relay that would power your fans (it could be 120v or 12v - just purchase the correct relay for you fan's voltage). When your thermostat turns on the AC unit, the relay provides power to the fans. You would have to have fair relay switch knowledge to install but not difficult.
Second, install a limit switch in the fan area and connect it to your fans. When you AC unit turns on, the limit switch would allow power to your fans. Positioning the limit switch in the airflow is the difficult part.