Computer fan in IndelB fridge (Webasto SECOP)

[coopso]

Has anyone tried upgrading their Indel fridge to make it quieter? I have a feeling the compressor is a little bit louder than the fan but obviously it's not practical to replace that whereas a fan should be a simple swap out!


So I would like to replace the fan in my IndelB fridge with a quieter one. I see there is some fan expertise here from other threads (@sternwake) ! Full disclosure: I also posted in another forum where I orginally found a lot of super detailed info on fans posted by sternwake. Not sure he's on that forum now though.


The existing fan is a two wire Young Lin Tech Ltd model DFB 922512L 92x92x25mm 12V 1.6W. I found a spec here:

The fan is connected to the SECOP fridge controller described here. The document states the controller can supply a continuous power of 6W. The document states that fan speed can be adjusted from 40% to 100% - since this is done with only two wires presumably the controller is using a PWM signal on the +ve fan input wire.

I've been in contact with Noctua who advise that all their fans require a permanent 12V connection and a separate PWM connection (so are 3 or 4 wires).


I have spent hours googling for 2 wire fans with PWM but haven't found any! One idea I have for a workaround is to take the + for the fan input from an alternate source and connect the fridge PWM signal wire to the PWM fan connection (3 wire fan). I'm not an electrician so not sure if that would work, plus I have a feeling that there are multiple PWM implementations out there.


Any ideas? Thanks.

[rvpopeye]

Welcome aboard coopso ! 

Glad to see you found us (and you're not a spammer!) LOL  
 Yes , Sternwake is hanging out here now . 

You sound like the "re-engineer your gear" type taking on that type of mod.
Any other mods you want to show off will get the proper oooooo's and ahhhhhhhhh's here ! 

I noticed in your app you're a member from another land so probably operating on a different time frame as us here   
Post a bit about yourself and the rig in which you travel and maybe where you like to camp out in the welcome center while you wait for him to show up. The group will want to welcome you too , and always remember . We like pictures !

 

[Shadowmoss]

Welcome. I live in a motorhome and go between 2 rv parks depending on the season. I read all I can so when the time comes to replace my ancient motorhome I will make more informed choices. In another life I used to work on electric/electro-mechanical stuff but now when I read I just know how many brain cells I've lost since my 20's.

[sternwake]

Saw your post on Cruisers forum, will respond here.

The Secop compressor controller adjusting the fan speed from 40 to 100%, is something new to me.

I can see obvious functional benefits to this method, but......

Noctua will say their fans are not designed to run with PWM speed control on the +(yellow) and negative(-) wires of their PWM 4 wire fans.

They expect their fans to be controlled on the 4th wire via a separate PWM signal wire from a PWM source, like a computer motherboard or their NA fc1 speed controller

I once went through many Industrial Noctua fans in a non fridge related application, using their Na-fc1 speed controller. The PWM wire always had issues with corrosion and the fans would fail in short order even protected to the best of my ability. I finally told them don;t bother sending another warranty replacement, and use Delta 38mm wide fans for that application instead.

I have one unused 3k rpm 140mm Noctua, that I have tested on a PWM motor speed controller without issue, but not a long term test.

but the PWM motor speed controller is 21Khz. Many PWM MSC's are like 13 KHZ and fans( and some LEDS) at reduced speeds/brightness, whine, and sound sick.

Feeding their fans 12v but PWM'd for speed control, is likely OK, but for some unknown amount of time. They have a 6 year warranty., so it is in their best interest to say nope, 12v only no PWM on + and - .

On another forum I know of one guy who runs several Noctua Industrial fans on PWM MSC feeding the power wires, and says they don't whine and have been going for years fed by a PWM MSC.

That said, I have NO idea what KHZ the Secop compressor controller will attempt to modulate the fan speed.

Reducing Compressor and condenser fan Noise is not too difficult.

I've seen on some other forums the plate which the compressor and condenser fan, where they attached to fridge body, to be overtightened, squashing the rubber vibration/ noise suppressing bushings. Simply backing off the screws a bit can do wonders for reducing the vibration and noise transmitted to the fridge body which can act a bit like a speaker. How it is mounted inside a cabinet also makes a huge difference.

a 92Mm fan can and will make much more noise than a larger fan, while moving less air .

I'm convinced the assemblers use whatever fan they can buy in bulk the cheapest that is around a 0.2 amp range. Most of the fans seem to be junky sleeve bearing fans with little thought to efficiency.

The 92mm fans I saw pics of, were simply zip tied to condenser, through the fins.
My Vitrifrigo came with a 120MM fan on the condenser and 4 screws holding it to the condenser's frame forecing all the air through all the condenser body.

it was assmebled to suck air through the condenser fins.
Computer fans, in my experience, without exception, get much louder when there is restriction behind the fan blades, instead of in front of them. They also move much less air when there is restriction behind, as opposed to in front.

I moved my fan to the other side of the condenser to push air into it.
I used a Noctua NF-f12, and later switch to a Noctua A12x15, which is thinner, and allowed the fan 10more MM to scavenge air from the insulated cabinet the extra insulated fridge resides within.

Initially, when I moved the fan I was recording ON OFF times, and the Noctua fan moved to the other side, pushing, reduced the average compressor run time about 45 to 50 seconds, from mid 5 minutes on to high 4, and ~ 15 minutes off. While all the variables were not strictly controlled I was convinced it was an improvement. Also the Noctua fan was heaps more quiet, and drew 0.07 amps less than the shitty 120mm fan Vitrifrigo provided.

The NF-F12 is rated at only 53 cfm, but has a high static pressure rating for that relatively low CFM. The VF provided fan was abut 72 cfm, but mounted to pull through the compressor its flow was tiny fraction of that amount.

The NF-F12 or a12x15 or a12x25 are all ~25$ fans, but all of them, when mounted to push air will outperform whatever 92mm fan they provided, for much less noise.

How well they deal with the PWM signal pon the powertwires 40 to 100% signal on the Yellow and black wires is an unknown and a risk you will have to decide whether it is worth it or not. A fan failure might not be obvious until the food spoils.

Mounting these fans to pull air through condenser is a waste.
I think that orientation is asinine and contemptible, and I also think 92 mm fan only partially covering the condenser fins is a huge waste.

My NF-f12 mounted to pull instead of push doubled its noise as the blades were stalled, unable to scavenge, but flipped around to push and the noise did not increase over that in free air.

Turning the fan around as opposed to putting the fan on the other side and the airflow direction the same, is something to be dictated by your fridge cabinet, but keep in mind the compressor controller has a finned heatsink on its backside and airflow across there,and compressor body, is important too.

While these 12vDC fridges are $$$, a little spit and polish can easily make them perform even better, using less battery power, making less noise.

If you not willing to potentially risk a 25$ Noctua, I would search out dual ball bearing 120mm fans from Delta, Nidec, and San Ace in the 0.2 amp or less range. Any of these mounted to push air through the condenser will outperform the 92mm higher rpm fan covering only a portion of the condenser. The static pressure rating is more important tha the CFm rating, and many fans which spec 0.25 amps, only draw that for 0.25 seconds while they fire up the blades, and then can draw only half their rating once spinning.
I've seen both though.

These fans should suck cool air and push it outside the cooling unit area so that this preheated air cannot be recycled. Mine sucks filtered air from the cool floor behind and below the fridge and exhausts it either out a louvered vent in summer, or into adjacent cabinet space which is also ventilated, in winter.

I can't hear my A12x15, or my compressor unless all other fans are off, on a quiet night, which they almost never are. The NF-f12 is now 8 years old, exhaustng the adjacent cabinet on one of their noise reduction cables to slow it down even more.

My previous fridge with a sawafuji 'swing compressor' annoyed the living shit out of me. It would cause bizarre harmonics and turn teh whole cabinet and van wall into a speaker. Its stainless door skin got riddled with frustrated knuckle dents.

More recently I found that my cabinet design, and a hole cut in the floor for the underbody batteries, heavily contributed to that swing compressor's harmonics. I added a diagonal to support that whole area from below, and was amazed at the reduction in not only road/tire noise at highway speeds, but I also now have to stick my ear upto the fridge door to determine whether the compressor is on or off. Is easier to stick my fingers in the intake and feel if the A12x15 is sucking air across them, or seeing ~2.5 more amps than expected on my ammeter.

I say try the NF-f12 pushing air into condenser. There were lots of used NF- f12s on E bay and similar once the A12x15 and a12x25 first came out.

The Secop controller feeding the 40 to 100% power signal on the power wires might make the copper windings in fan motor whine at reduced speeds. or it might not. The whine might be tolerable to you, or not.

I am intolerant of whining. That PWm signal might stress some components on the circuit board, reducing their lifespan, or not.

Other dual ball bearing fans can be disassembled and one can paint the motor windings with clear nail polish to perhaps stop them whining. Cant remove and then successfully return the impeller on Noctua's though.

I have used a PWm signal generator on powerful Delta PWM fans 4th wire, and found that it had a much better speed control down low when using a voltage bucker on the power wires instead. It also used slightly less current not having to power the signal generator separately.

The 4 wire PWm fans...well I don;t bother with the rpm wire or the PWM signal wires and if a specific fan only comes with 2 wires, all the better.

Covering the solder joints where the wires enter the hub's circuit board, is Key to fan longevity.
I use amazing goop to do this and give it 5 days for stink to subside, but clear nail polish is good too.

High static pressure fans have more scythe like larger blades jutting forward, where high cfm fans generally have shorter more steeply angled blades.

The fridge application calls for high static pressure fans, and one Noctua A12x25 is said to outperform two NF-F12's mounted in a push pull configuration.

I go into lots more detail about the evolution of my ventilation in my 'tales from a ventilationlNazi/ lunatic / enthusiast' thread.

Best thing you can do for your New Indel is get that 92mm sleeve bearing fan out of there. and replace it with a 120mm fan pushing.
The NF-f12 is a pretty epic fan for this choice in my opinion
My Noctua A12x15 draws more amperage but is even quieter in my cabinet and was a completely unneeded modification.

The A12x25 is the computer nerd's newest favorite, AFAIK. I just cant say how long it will be happy with PWM on the yellow and black wires. It might not be an issue, or perhaps just last 5 years instead of 7, or perhaps only last a few days/ months, which in my opinion is unlikely, but I've not done it for any extended period to say for sure.

The sleeve bearing 92mm fan it came with would be lucky to last 2 years if you were near a salty coastline.
.

[rvpopeye]

And THAT's why we call him GURU !

[tx2sturgis]

And we are his biggest 'fans'....

[coopso]

Thanks folks, I will order the Noctua F12 and an adaptor, will paint the joints with nail polish and mount the fan in reverse. I'm pretty sure the fan won't mount the other side of the condenser but will mount it there instead if I can!

The other thing I will look at is how the condenser and compressor are monted, as they both seem attached to a thin metal frame with metal screws, there's no vibration suppression at all.

Thanks for the tips! I'll report back.