Replacing FANS inside the EG4 6500EX-48 to make it quiet

[fmeili1]

Finally I've finished the work on the active mini split cooling for the AIO's. Now I hope that the fan's will never speed up to full speed anymore with the modded temperature controlled fans.

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The 9,000BTU concealed ducted indoor unit is more than enough to cool the system down and it's very energy efficient (about 700W). When I have an ambient of 20°C in the garage, I measure between 5-8°C on the AIO cold air inlets. Looking forward how it will behave when we will have 120 Fahrenheit here in the desert in the next summer with full working MPPT chargers...



This is the temperature graph from SA with all 6 AIO's at idle, turned on at about 6:30am without active cooling. At about 8:15am I've turned on the mini split.


As a side effect, the batteries which are located under the AIO's are also get's a bit cooled because not all of the cold air is sucked in by the AIO's and fall down on top of the batteries (for unknown reasons, 2 of theAIO's will always be about 10°C hotter than the other 4 - this was right from the beginning but they working without any problems... it doesn't matter if they are just idling or under inverter and/or charger load).

 

[rhino]

Looks pretty elaborate but at least you'll have cooler units now.. By the way, what size wire way is that you are using.. is it 8x8 or 6x6?

 

[fmeili1]

Looks pretty elaborate but at least you'll have cooler units now.. By the way, what size wire way is that you are using.. is it 8x8 or 6x6?

These are two 6x6x72 Hoffmann wireways connected together (and two smaller 4x4 under the AC-out and AC-in breaker panels).

 

[HowlerMonkey]

Schweet!

 

[fmeili1]

Short update about the temperature behavior with the active cooling after the first 30 days of my system in production (the system was finally completed on April 26th. put into operation - no issues, 100% covered by solar, no grid used).

The following charts showing the AIO temperatures, the house load, the PV production, the battery current and the garage ambient temperature.






Over the last 30 days I've done some changes with the control algorithm for the equipment cooling ducted minisplit in my smart home system. It heats up fast here in the desert and even with a bit higher ambient in the (conditioned) garage and some higher house load, the AIO's are nice cold (and because of that, not very loud anymore). The hottest temperatures occur between midday and 1 p.m., when the highest PV production occurs to charge the batteries while driving the load in parallel, but even at this time the AIO's are way more silent compared to the unmodded units.

I'm absolutely happy with the fan modding and the results. Even under high loads, they usually remain below 50 degrees Celsius, which will hopefully lead to a significantly longer service life (the electrolytic capacitors and FETs/IGBts will be happy) - in addition to the lower noise nuisance!

 

[Gurusi]

Hey, been following and using this thread for cooling my system. Currently I have x2 lv6548’s and am in the process of adding two more.

I went with a 8” in-line fan ducting from outside through an inline filter directly to the upper vents.

It seems to work well and am waiting for the pwm controllers to add to the x3 fans in each inverter.

Currently I have the 8” inline fan thermostat stuck at the bottom of one of the inverters vent to pickup on the temp increase (and the inline fan turns on and off as needed).

I plan to place the thermostat in one of the inverters but can’t decide which of the three heat transfer boards to fix it on. Any opinions? I’m leaning to the Main board.


I am also unsure what my target cooling temp should be overnight? Since installing the inline fan I’m getting around 80F/26C to 90F/32C overnight and peaks of 125F/51C when charging and using high loads (was previously hitting 160F/71C). I want it cool but don’t want to be needlessly running the fans overnight using battery power.


Edit:- SA screenshot shows before and after install


Thanks

 

[fmeili1]

Hey, been following and using this thread for cooling my system. Currently I have x2 lv6548’s and am in the process of adding two more.

I went with a 8” in-line fan ducting from outside through an inline filter directly to the upper vents.

It seems to work well and am waiting for the pwm controllers to add to the x3 fans in each inverter.

Currently I have the 8” inline fan thermostat stuck at the bottom of one of the inverters vent to pickup on the temp increase (and the inline fan turns on and off as needed).

I plan to place the thermostat in one of the inverters but can’t decide which of the three heat transfer boards to fix it on. Any opinions? I’m leaning to the Main board.

Nice job!

I am also unsure what my target cooling temp should be overnight? Since installing the inline fan I’m getting around 80F/26C to 90F/32C overnight and peaks of 125F/51C when charging and using high loads (was previously hitting 160F/71C). I want it cool but don’t want to be needlessly running the fans overnight using battery power.

This was also my biggest question at the beginning - how to control the mini split target temperature, based on which data. After thinking a lot about PID controllers (which is not the right solution for this) I found the following controlling algorithm for my system.

I adjust the mini split target temperature based on the following parameters (I get these values from Solar Assistant via MQTT into my smart home system where the rules are implemented to control the target temperature of the mini split).

• highest inverter temperature
• ambient temperature in the garage
• current PV production
• battery SOC
• battery charging current
• PV power

These are the rules I'm using:

• If SOC>=99% OR battery charging with >6000W OR PV production is >10,000W, the mini split will be set to max. cooling (17°C) and HIGH fan speed (in this case there is enough power to just "over-cool" the unit - I think this will help to increase the life of the components and the power is available anyway - typical mode while full sun).
• else if the highest AIO temperature is <45°C, the target temperature is set to the same value as the garage ambient temperature and LOW fan speed (I found that even with the same target temperature as the ambient, there is enough cold air coming out of the mini split while using having very low energy consumption) - typical mode in the night.
• else if the highest AIO temperature is <50°C the target will be set to 1°C below garage ambient to increase the cooling (fan LOW)
• else if the highest AIO temperature is >=50°C and <52°C the target will be set to 2°C below garage ambient to even more increase the cooling (fan LOW)
• else if the highest AIO temperature is >=52°C and <54°C the target will be set to 3°C below garage ambient to even more increase the cooling (fan LOW)
• else if the highest AIO temperature is >54°C the target will be set to 17°C with HIGH fan speed

This control rule works great for my system.

Even if you don't have all these data in your case, I think you should depend the target temperature of the AC mostly on the garage ambient and not on a value measured inside of the AIO.

 

[Gurusi]

Nice job!

This was also my biggest question at the beginning - how to control the mini split target temperature, based on which data. After thinking a lot about PID controllers (which is not the right solution for this) I found the following controlling algorithm for my system.

I adjust the mini split target temperature based on the following parameters (I get these values from Solar Assistant via MQTT into my smart home system where the rules are implemented to control the target temperature of the mini split).

• highest inverter temperature
• ambient temperature in the garage
• current PV production
• battery SOC
• battery charging current
• PV power

These are the rules I'm using:

• If SOC>=99% OR battery charging with >6000W OR PV production is >10,000W, the mini split will be set to max. cooling (17°C) and HIGH fan speed (in this case there is enough power to just "over-cool" the unit - I think this will help to increase the life of the components and the power is available anyway - typical mode while full sun).
• else if the highest AIO temperature is <45°C, the target temperature is set to the same value as the garage ambient temperature and LOW fan speed (I found that even with the same target temperature as the ambient, there is enough cold air coming out of the mini split while using having very low energy consumption) - typical mode in the night.
• else if the highest AIO temperature is <50°C the target will be set to 1°C below garage ambient to increase the cooling (fan LOW)
• else if the highest AIO temperature is >=50°C and <52°C the target will be set to 2°C below garage ambient to even more increase the cooling (fan LOW)
• else if the highest AIO temperature is >=52°C and <54°C the target will be set to 3°C below garage ambient to even more increase the cooling (fan LOW)
• else if the highest AIO temperature is >54°C the target will be set to 17°C with HIGH fan speed

This control rule works great for my system.

Even if you don't have all these data in your case, I think you should depend the target temperature of the AC mostly on the garage ambient and not on a value measured inside of the AIO.

Wow, thanks for the detailed response. Unfortunately I don’t have any access to the additional data you mentioned.

You mentioned using the garage ambient temperature. Would it matter that the inverter intakes are locked out from the garage air? As the intake draws from outside of the house/garage. It does however exhaust heat into the room. Perhaps the target temp should be based on the outside ambient temp?

 

[fmeili1]

Wow, thanks for the detailed response. Unfortunately I don’t have any access to the additional data you mentioned.

You mentioned using the garage ambient temperature. Would it matter that the inverter intakes are locked out from the garage air? As the intake draws from outside of the house/garage. It does however exhaust heat into the room. Perhaps the target temp should be based on the outside ambient temp?

I live in the hot desert and my outside air is usually always hotter than the garage air (the garage is also cooled, at least a bit). That's the reason why I use the garage air for the inlet, also.
You just need to achive that the AC cools at least "a bit" to blow cold air out, which will be enough for the equipment cooling. To set the target to the same value or 1 degree below compared to the incoming air temperature, you need to know thus incoming air tempeeature. It doesn't matter if this is your outside air or the air sucked in from inside the room.

 

[Mimesis]

Before this thread went down the very deep rabbit hole of reversing fans, adding temperature controllers, fabricating 3D-printed ductwork, and installing active cooling, it started with a relatively simple idea: to replace the noisy OEM fans with quieter aftermarket ones. However, that was abandoned when the Noctua fans proved not to be powerful enough.

I still wonder: is there some other 80mm 12V fan on the market that can meet the OEM static pressure and airflow specs (0.7 inch H2O & ~30CFM), and yet is at least somewhat quieter? Noctua can't be the only game in town. I came across a company (ATO) that claims that their DC8025BLH model fan puts out 33 CFM at 2800RPM, with a noise level of 32dBA. While that's much higher than the Noctua, that must be significantly quieter than the OEM fan. They also offer lots of connector/pinout wiring options.

Or maybe this Artic 3000RPM fan, which puts out 1.0 in H2O and 23CFM at 22dBA?

I'd really like to start with this simple solution, but I have to admit that I don't really know anything about these small fans. What am I missing?

 

[adobopr]

Before this thread went down the very deep rabbit hole of reversing fans, adding temperature controllers, fabricating 3D-printed ductwork, and installing active cooling, it started with a relatively simple idea: to replace the noisy OEM fans with quieter aftermarket ones. However, that was abandoned when the Noctua fans proved not to be powerful enough.

I still wonder: is there some other 80mm 12V fan on the market that can meet the OEM static pressure and airflow specs (0.7 inch H2O & ~30CFM), and yet is at least somewhat quieter? Noctua can't be the only game in town. I came across a company (ATO) that claims that their DC8025BLH model fan puts out 33 CFM at 2800RPM, with a noise level of 32dBA. While that's much higher than the Noctua, that must be significantly quieter than the OEM fan. They also offer lots of connector/pinout wiring options.

Or maybe this Artic 3000RPM fan, which puts out 1.0 mm H2O and 23CFM at 22dBA?

I'd really like to start with this simple solution, but I have to admit that I don't really know anything about these small fans. What am I missing?

After swapping my 6500EXs for a 18kPV, the highest temp my 18kPV reaches is lower than the lowest temps reached by my 6500EX. I really think these units need more cooling if anything.

 

[fmeili1]

Before this thread went down the very deep rabbit hole of reversing fans, adding temperature controllers, fabricating 3D-printed ductwork, and installing active cooling, it started with a relatively simple idea: to replace the noisy OEM fans with quieter aftermarket ones. However, that was abandoned when the Noctua fans proved not to be powerful enough.

right

I still wonder: is there some other 80mm 12V fan on the market that can meet the OEM static pressure and airflow specs (0.7 inch H2O & ~30CFM), and yet is at least somewhat quieter? Noctua can't be the only game in town. I came across a company (ATO) that claims that their DC8025BLH model fan puts out 33 CFM at 2800RPM, with a noise level of 32dBA. While that's much higher than the Noctua, that must be significantly quieter than the OEM fan. They also offer lots of connector/pinout wiring options.

Or maybe this Artic 3000RPM fan, which puts out 1.0 in H2O and 23CFM at 22dBA?

I'd really like to start with this simple solution, but I have to admit that I don't really know anything about these small fans. What am I missing?

I had already purchased these devices and it took many months for me to notice the initial installation and the noise problem. Since I have no alternative location for the AIOs, I had to find a solution - even if it involved a lot of effort.

I'm pretty sure you'll have to live with the noise. Unfortunately, the only alternative is the route I chose (modify the fan to be temperature-controlled AND actively cool it). It was a lot of extra work and I wasn't really happy about having to do it, but at least it works great.

 

[Mimesis]

right

I had already purchased these devices and it took many months for me to notice the initial installation and the noise problem. Since I have no alternative location for the AIOs, I had to find a solution - even if it involved a lot of effort.

I'm pretty sure you'll have to live with the noise. Unfortunately, the only alternative is the route I chose (modify the fan to be temperature-controlled AND actively cool it). It was a lot of extra work and I wasn't really happy about having to do it, but at least it works great.

All due respect (even awe) at the work you did, but it's well beyond my capabilities. I still wonder whether a different fan with the right specs could help, at least marginally.

 

[fmeili1]

All due respect (even awe) at the work you did, but it's well beyond my capabilities. I still wonder whether a different fan with the right specs could help, at least marginally.

I really don't see any easy solution until you'll be able to find a replacement fan with the same physical data AND is quiet. I don't know it these will even exists.

 

[rcrracer]

https://www.digikey.com/en/products/filter/fans/dc-brushless-fans-bldc/217

select column/filters

 

[fmeili1]

I found the original fan data (at least very close):

https://www.digikey.com/en/products/filter/fans/dc-brushless-fans-bldc/217

select column/filters

Two fans on the right side (inverter), 92mm x 92mm x 25mm
2x DA09225B12VH-RevF03 DC12V 1.05Amp (Huaxia Hengtai)
sepc: http://szhxht.cn/en/Products/info_itemid_14261.html
12V, 1A, 12W, 6000RPM, 105.95CFM, 3m^3/min, 0.72Inch-H2O, 180.52Pa, 54dBA, 78g
or
2x DA09225B12VH-RevF04 DC12V
spec: http://szhxht.cn/en/Products/info_itemid_14261.html
12V, 1A, 12W, 5500RPM, 96.24CFM, 2.73m^3/min, 0.65Inch-H2O, 139.10Pa, 54dBA, 78g

One fan on the left side (MPPT), 80mm x 80mm x 38mm
1x YDH8038B12 DC12V0.65A (YCCFAN)
spec: https://www.yccfan.com/productdetail/dc8038srfs53.html
12V, 0.50A, 5000RPM (with 0.65A it’s more like 6000RPM?), 61.77 CFM, 14.84mmH2O, 49.80dBA, 170g
or
spec: https://www.yccfan.com/productdetail/dc8038fsrfs30.html
12V, 0.62A, 4500RPM (should be 5000RPM with 0.65A?), 34.48CFM, 11.16mmH2O,40.09dBA, 254g


I found not very many options for replacement fans. Most of the possible options from DigiKey are only available in quantities >500 or not available. But even if they would be available, they are all not quiet.

 

[fmeili1]

I've changed the air shield a bit to make it more like a cold air trap. This easy change improves the cooling even more and the inverter temperatures are about 2-3°C (4-6°F) cooler at the same load which makes them even more quiet.

First picture shows the original version with just the 45° shield and the second picture shows the enhanced version with a vertical barrier on top front of the 45° shield:

Since 2.5 weeks we have a massive heat dome here over the Mohave desert and the max. outside shade temperatures are every day between 115-126°F. The central heat pump and the mini splits are running for long times with very high load. Here is a typical load chart from yesterday and today:

I need >10kW permanent load for more than 8h in a row with some peaks up to 16kW. But even under these harsh conditions, the inverter temperatures are really nice cold and as a result they are really quiet. Most of the time the temperatures stay below 50°C, for some short peaks it may hit the 55°C. (btw. I need daily grid support since the beginning of the heat wave because my max. PV energy is not longer able to cover the house load if the outside max. temperatures will go above 104°F. On 4th of July we hit 129°F and my house consumption was 182kWh in just one day - just unbelievable - if we are below 104°F we need <90kWh per day and the PV and batteries are able to cover the whole house load).

 

[Bananaman321]

what about a short piece of ducting 4-8in long made of aluminum flashing sheet metal cardboard ect. lined with sound absorbing material felt carpet foam attached to the inverter fans exhaust.
I have made made covers for generators out of wood and metal lined with sound absorbing material like egg crate foam or old repurposed AC duct board that work incredibly well
also just lining the area directly behind the exhaust and protruding out say 6in with similar material will help.
Just an idea Good luck

 

[fmeili1]

what about a short piece of ducting 4-8in long made of aluminum flashing sheet metal cardboard ect. lined with sound absorbing material felt carpet foam attached to the inverter fans exhaust.
I have made made covers for generators out of wood and metal lined with sound absorbing material like egg crate foam or old repurposed AC duct board that work incredibly well
also just lining the area directly behind the exhaust and protruding out say 6in with similar material will help.
Just an idea Good luck

Good ideas! Your are right, a lot of additional things could be done to further reduce the noise level from the noise insulation point of view.

But luckily, with my current setup it quiet enough for me. The only thing I've done on top of the active cooling and temperature based fan speed controlling, I've added rubber rings around all mounting holes between the AIOs and the wall to reduce vibrations which may be transferred through the wall.

 

[Bananaman321]

Good ideas! Your are right, a lot of additional things could be done to further reduce the noise level from the noise insulation point of view.

But luckily, with my current setup it quiet enough for me. The only thing I've done on top of the active cooling and temperature based fan speed controlling, I've added rubber rings around all mounting holes between the AIOs and the wall to reduce vibrations which may be transferred through the wall.

BTW beautiful set up you wouldn't happen to suffer from OCD would you?

I know I do but it's in an odd way I can be working on the biggest piece of crap and all my fasteners have to match or all my washers have to be the same size