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Weather Station Hardware => Davis Instruments Weather Stations => Topic started by: fkapp on November 16, 2020, 07:09:43 PM
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Hi guys,
I am planning the next modification for my VP2 which is AC fan along with the 24 x7 Davis kit Ryan at scaled instruments sells.
Is 50 cfm too much flow?
I am located in Buffalo NY, and noticed that on calm/ low wind winter nights my 7714 shield runs few degrees colder than NWS office few miles away. Not super hot climate so dont want to "over correct" and create inaccuracy by too much flow
I am looking at this fan:
https://www.acinfinity.com/component-cooling/axial-ac-fan-kits/axial-1225-muffin-120v-ac-cooling-fan-120mm-x-120mm-x-25mm-low-speed/?gclid=Cj0KCQiA48j9BRC-ARIsAMQu3WQcLMitUa7VDlfs_R7SRznsC5GaHZZ_FFm5H30yezhEJvvnOH9IsRgaAg5gEALw_wcB (https://www.acinfinity.com/component-cooling/axial-ac-fan-kits/axial-1225-muffin-120v-ac-cooling-fan-120mm-x-120mm-x-25mm-low-speed/?gclid=Cj0KCQiA48j9BRC-ARIsAMQu3WQcLMitUa7VDlfs_R7SRznsC5GaHZZ_FFm5H30yezhEJvvnOH9IsRgaAg5gEALw_wcB)
Any recommendations out there for Fan would also be welcomed?
Thanks guys as enjoying tinkering and tuning my station
Frank
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This fan is physically too big, you need 80x80x25 mm. Also, the 1800 is rpm's, not CFM, which is at 51, which is overkill. Something between 20 and 40 CFM will do the job easily.
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I noticed my typo just now, thanks for correcting.
Any recommendations?
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Any recommendations?
Not really, there's a million to choose from.
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what dimensions for the fan are needed if 80mm x80mm x25 mm is too big?
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what dimensions for the fan are needed if 80mm x80mm x25 mm is too big?
You DO have a 24hr FARS VP2, right?
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Maybe this one IP67 rated for dust and water. https://www.amazon.com/Coolerguys-80mm-80X80X25-Airflow-Waterproof/dp/B07VWLSMN1/ref=sr_1_6?dchild=1&keywords=80mm+25mm+New+Case+Fan+12V+DC+IP55+Waterproof+67CFM&qid=1605575329&s=electronics&sr=1-6 (https://www.amazon.com/Coolerguys-80mm-80X80X25-Airflow-Waterproof/dp/B07VWLSMN1/ref=sr_1_6?dchild=1&keywords=80mm+25mm+New+Case+Fan+12V+DC+IP55+Waterproof+67CFM&qid=1605575329&s=electronics&sr=1-6).
Doug
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As my original post says I have a VP2 and am in the process of planning a 24x7 FARS which am reading about/ asking for guidance.
Was trying to order the fan needed in parallel to the non solar and battery components from Ryan and ask for some help from those who have already have made this mod.
Apparently that's not the way we roll these days on this forum based on your last statement to CW2274
Read the reams of information and ask a question at ones risk!
Anyways:
From reading through the past topics on the forum around AC FARS 80mm x 80mm x 25mm and less than 40 cfm will work.
My plan will be to order this fan
https://www.acinfinity.com/component-cooling/axial-ac-fan-kits/axial-8025-muffin-120v-ac-cooling-fan-80mm-x-80mm-x-25mm/?gclid=Cj0KCQiA48j9BRC-ARIsAMQu3WQ9ViTeVac7USrtSNz9hi1rGyY1qjfANU6BT2IUk8oTDFLp2MPHS04aAvJAEALw_wcB (https://www.acinfinity.com/component-cooling/axial-ac-fan-kits/axial-8025-muffin-120v-ac-cooling-fan-80mm-x-80mm-x-25mm/?gclid=Cj0KCQiA48j9BRC-ARIsAMQu3WQ9ViTeVac7USrtSNz9hi1rGyY1qjfANU6BT2IUk8oTDFLp2MPHS04aAvJAEALw_wcB)
and this extension cord to get to GFI in water tight outlet cover I will be installing.
https://www.acinfinity.com/component-cooling/axial-fan-accessories/120in-fan-power-plug-cord/?gclid=Cj0KCQiA48j9BRC-ARIsAMQu3WQzyngBuKaKLBQ460JSPg1tbI-DmWHi1hdWLLbSCtQCQpN0qJMkv0AaAryCEALw_wcB
(https://www.acinfinity.com/component-cooling/axial-fan-accessories/120in-fan-power-plug-cord/?gclid=Cj0KCQiA48j9BRC-ARIsAMQu3WQzyngBuKaKLBQ460JSPg1tbI-DmWHi1hdWLLbSCtQCQpN0qJMkv0AaAryCEALw_wcB)
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Apparently that's not the way we roll these days on this forum based on your last statement to CW2274
Read the reams of information and ask a question at ones risk!
Not sure if that's a dig at myself, but what bothers me regardless is that you come on here asking for help then then ask me if it's not the right size after just telling you the other one was too big. Seriously? Why in the hell would I do that? I've had my 80x80x25 mm fan in my ISS for 7ish years and it still fits now just like it did when I installed it. :roll:
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Being in Buffalo, you may want to pay attention to the fan’s temp rating. Looks like the one you’re looking at is rated to 0F. Even an optimist would probably want something rated colder in a Buffalo winter.
Others may too, but I know coolerguys.com has some 80x80s rated down to -40F.
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Yeah so the first one i listed was too big. I simply asked for a clarification (sorry i missed you listed the 80mm x 80mm x 25mm ) recommendation and didnt appreciate DO comment.
This IS a hobby and am on here exhausted so missed read your response. My comment to you is when someone asks a well intended question or is confused ease up a bit as most people are on here to relax.
Anyways thanks for the input on cfm and dimensions and lets drop this and enjoy the rest of the evening.
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Thanks for the guidance on temp rating.
The search continues [tup] and found this:
https://www.coolerguys.com/products/mechatronics-80-x-25mm-ac-115v-fan-uf80b12-bth (https://www.coolerguys.com/products/mechatronics-80-x-25mm-ac-115v-fan-uf80b12-bth)
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The above fan is what I have been using for two years without any problems and still going strong. My station is located in Moorhead Mn and past 2 years been running with temperatures of -28° to 98°. Only problem I have had is the screen will frost over on a cold frosty morning so have to brush off the screen to get air flowing again. Snow has never been a problem.
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Thanks for the help with the fan.
What did you guys use to seal the opening between the Fan casing and the welded core?
Not sure what is best to avoid moisture collecting in material
Thanks as looking forward to building this out soon.
Frank
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Thanks for the guidance on temp rating.
The search continues [tup] and found this:
https://www.coolerguys.com/products/mechatronics-80-x-25mm-ac-115v-fan-uf80b12-bth (https://www.coolerguys.com/products/mechatronics-80-x-25mm-ac-115v-fan-uf80b12-bth)
sorry, but this fan that I see in the link, should replace the fan that is in the ventilated davis? that is this? [ You are not allowed to view attachments ]
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An 80x80mm will drop right in after you snip the mounting ears down a bit. I used a pair of end-snips. Planning on going in my ISS today to change my temp/humidty sensor. Will try and remember to snap a couple of pictures.
Doug
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Thanks man. Would appreciate it.
Reading online some guys it sounds like putty or insulate around the case to seal up other than fan. Pictures will help with what works .
Thanks again
Frank
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The link is to a blog I did on upgrading the fan, the reason for it being 12v was my rainbucket heating resistors use 24v, so I already had a low voltage supply at the ISS
https://www.chatteris.biz/blog/davis-fars-upgrade-monitored-pc-fan/ (https://www.chatteris.biz/blog/davis-fars-upgrade-monitored-pc-fan/)
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The link is to a blog I did on upgrading the fan, the reason for it being 12v was my rainbucket heating resistors use 24v, so I already had a low voltage supply at the ISS
How is it possible that your case fan flows almost half as much as the stock fan? :???: Mine's like a vacuum cleaner compared to stock, and it's not sealed in either. The bottom wasn't blocked when you tested was it?
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The link is to a blog I did on upgrading the fan, the reason for it being 12v was my rainbucket heating resistors use 24v, so I already had a low voltage supply at the ISS
How is it possible that your case fan flows almost half as much as the stock fan? :???: Mine's like a vacuum cleaner compared to stock, and it's not sealed in either. The bottom wasn't blocked when you tested was it?
No the plates were all attached on the shield and nothing was blocked.
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The link is to a blog I did on upgrading the fan, the reason for it being 12v was my rainbucket heating resistors use 24v, so I already had a low voltage supply at the ISS
How is it possible that your case fan flows almost half as much as the stock fan? :???: Mine's like a vacuum cleaner compared to stock, and it's not sealed in either. The bottom wasn't blocked when you tested was it?
No the plates were all attached on the shield and nothing was blocked.
Wow. That makes no sense to me.
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Why did you wrap the case with the insulating foam?is this necessary or can just wedge fan case in?
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Why did you wrap the case with the insulating foam?is this necessary or can just wedge fan case in?
The fan neatly sits in the recess when the fan edges have been rounded down a bit, the first time I used a fan I used the foam strip to fill the gaps as I thought this would increase the ‘throughput’ of the air past the sensor via the fan, when the fan fail and I replaced it, I didn’t use the foam as I believe enough air is being drawn past the sensor.
I did a toilet paper test around the shield to prove that their was a slight negative pressure.
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The link is to a blog I did on upgrading the fan, the reason for it being 12v was my rainbucket heating resistors use 24v, so I already had a low voltage supply at the ISS
How is it possible that your case fan flows almost half as much as the stock fan? :???: Mine's like a vacuum cleaner compared to stock, and it's not sealed in either. The bottom wasn't blocked when you tested was it?
No the plates were all attached on the shield and nothing was blocked.
Wow. That makes no sense to me.
When I next service/ replace the fan I’ll repeat the reading in case I’ve made a mistake, the fan is certainly very quiet and even on the bench it didn’t seem as powerful as other fans I’ve taken out of computers, which made it ideal as I’ve read that you can introduce a cooling effect rather than simple ensure an air flow removing static air, but I’m certainly no expert here 😊
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Thanks. AWL how did the iss maintainence go?
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Thanks. AWL how did the iss maintainence go?
Why did you change out sht?
Well.....The package with my new ISS plates was supposed to be here Friday. Tracking now shows it will be here tomorrow.
Plan is to change sensor and plates at the same time. Hopefully tomorrow afternoon???? The sensor was spiking high humidity especially on days over 90F. Shooting my dew point and heat index up there in world record territory!
Doug
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Any luck?
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Out of curiosity what does the stock davis solar powered fan on the 24x7 FARS cfm run when full charged?
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Davis used to list the full sun aspiration rate at 190ft/min. I’ve noticed more recently they’ve listed that now as the intake flow rate and have the sensor chamber flow rate at 500ft/min. With the sensor chamber diameter of 2.26”, if my math is right, that should work out to just under 14CFM.
Flow rates:
https://www.davisinstruments.com/product_documents/weather/spec_sheets/DS7714_6838_Rad%20Shields_Spec_Sheet.pdf
Sensor chamber diameter:
https://www.davisinstruments.com/product_documents/weather/spec_sheets/7755_spec.pdf
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Thanks for the help with the CFM calc.
I am going to be ordering the 24 x 7 FARS kit from scaled instruments.
Question:
Do I need this fan deflector part if I am using AC fan?
https://www.scaledinstruments.com/shop/davis-instruments/parts/vantage-pro2-parts/radiation-shield-parts/davis-7342-508-vantage-pro2-24-hr-spars-insulating-sleeve/ (https://www.scaledinstruments.com/shop/davis-instruments/parts/vantage-pro2-parts/radiation-shield-parts/davis-7342-508-vantage-pro2-24-hr-spars-insulating-sleeve/)
Thanks guys
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Is foam weatherstripping recommended to seal up area around case fan if one is going to go ac fars fan route?
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Is foam weatherstripping recommended to seal up area around case fan if one is going to go ac fars fan route?
Personally, I use nothing. 60CFM pulls plenty without.
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Thanks for quick response.
How is the low battery glitch going?
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Thankfully the glitch hasn't been back since I went out to the ISS and pulled the battery to check it and the solar panel. Just one of those "things" I guess...
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Good news!
Are these critical parts for the 24x7 FARS?
Davis 7342.508 – Vantage Pro2 24-Hr SPARS insulating Sleeve
Davis 7353.065 – 24-Hour SPARS Temperature Humidity Sensor Mounting Plate
Seems like they are for extra insulation, but with good airflow not sure how much really need them.
Thanks
Frank
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The plate is what the sensors is mounted to and slides into the groove of the sleeve to secure it. Whether you need this stuff, no idea since I'm not sure exactly what you're trying to do. Almost sounds like you should buy the 24hr shield only and be done with it. That is IF you plan on it having a fan. The 24hr shield is not designed to be passive.
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Thanks. Currently have dfars and want to convert it to 24x7.
The conversion guide on scaled instruments site doesn't list the core or insulator or this mounting plate.
Was curious as debating getting these too or just mod dfars to have fan run all time
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I don't believe DFARS will even accept the solid core, hence why it's not offered.
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Yeap. Need to buy 4 of the plates with drop holes
From reviewing the exploded view
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Update here that I went in with the 24 x 7 ac fan mod.
Building tonight installing tomorrow.
Sharing and want to say thanks to everyone for all the input and sharing their experience with this mod.
Curious if you guys use the screen at bottom of core or leave off?
Thanks and looking fwd to this upgrade
Frank
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Looks great! Leave the screen on, no need sucking up bugs ect. gumming up the sensor chamber and fan blades more than necessary.
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Makes sense. Will send update when up
Thanks
Frank
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Hey guys, would 46cfm be too high/low? I would buy that fan from near the beginning of the thread but with Amazon adding VAT it comes out at stupid money, I have however found an IP68 jobby (https://fr.aliexpress.com/item/1005002474149380.html?src=google&src=google&albch=shopping&acnt=494-037-6276&slnk=&plac=&mtctp=&albbt=Google_7_shopping&albagn=888888&isSmbAutoCall=false&needSmbHouyi=false&albcp=9317296204&albag=99548979972&trgt=536572975094&crea=en1005002474149380&netw=u&device=c&albpg=536572975094&albpd=en1005002474149380&gclid=CjwKCAjwz5iMBhAEEiwAMEAwGJO95jrKX4bYmMxOFSN2NU74x8KUhr_ozr60ypvO9KUfkYg0OuiyghoCiZwQAvD_BwE&gclsrc=aw.ds&aff_fcid=e31366e88a204070ad82d88964df3c53-1636267632469-09369-UneMJZVf&aff_fsk=UneMJZVf&aff_platform=aaf&sk=UneMJZVf&aff_trace_key=e31366e88a204070ad82d88964df3c53-1636267632469-09369-UneMJZVf&terminal_id=2a1214cbd6ce47ea8a9500d91c488ac7) on AliExpress and i will take my chances with VAT when it arrives, its cheap enough so they might let it go through, normally do.
I normally use standard PC case fans, chop off the corners and job done but they tend to only last a year before that start making noise, i normally swap them out when that starts and its normal when the temps hit <10C and only gets louder the cooler it gets. This year i didn't change it dure to back issues so for now i have added a smart plug to shut it down when the temps are sub 7C, crude but its works well.
So i am really looking at one for next year but if the fan finally fails, i want the new fan at hand so I can readily swap it out, so if the one above is ok, I will get it, thanks :)
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I think depends on climate in. Here in Buffalo the one I went with is 24 cfm. Unless in hot climate don't think need more than 40 cfm but will lets see what guys that have been running ac fans longer say.
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Up an running and mod went smooth. Thanks again everyone for help.
Note: this is not main anemometer ( that is up on roof), have this one cause had iss slot avail and use to compare backyard level winds near garden for et etc.
Uv and solar face south
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You may notice the temperature change quickly, because more airflow is going thru the sensor now. If it's too much, you could wire something in that drops the voltage to the fan. In Winter here, in my little science project I have linked below, it switches the fan from full voltage to 1/2 of it thru a 6V voltage regulator so it drops down to 1600rpm at night when it's cold, otherwise the temperature changes too rapidly for my liking.
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Hi,
Thanks for the tip.
Wonder if that is what is happening this evening see attachment below with temp falling fast and mesowest noting suspect data.
The fan I am using is:
https://www.coolerguys.com/products/mechatronics-80-x-25mm-ac-115v-fan-uf80b12-bth?variant=17667344517&utm_source=google&utm_medium=cpc&adpos=&scid=scplpshopify_US_5592657477_17667344517&sc_intid=shopify_US_5592657477_17667344517&gclid=Cj0KCQiAsqOMBhDFARIsAFBTN3evlYKb6T01AwGYcrJWRAN6le2buz36OOpGo61fPUW-InCDPPjUz9gaAoTYEALw_wcB
That is a pretty sophisicated setup you have there. I am not an electronics expert so not sure can pull that setup off.
Would something like this work?
https://www.amazon.com/Electronic-Controller-Variable-Adjuster-Hydroponics/dp/B07T9BLJ7L/ref=sr_1_5?keywords=Fan+Speed+Control&qid=1636418882&sr=8-5
I know there is a plug with controller inline from the fan manufacturer, but that presents 2 issues (one aesthetics, and 2nd will be extra place need weather proof box)
Would be nice to have something can control from inside when is freezing out, if have any tips on guides/ ideas on more automated/control from not going out to station to change dial would help. like your setup so hope a simpler version is possible so can give it a shot.
Thanks
Frank
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Wonder if that is what is happening this evening see attachment below with temp falling fast and mesowest noting suspect data.
You were flagged briefly for the dew point. The abrupt spiking does look curious.
https://mesowest.utah.edu/cgi-bin/droman/regress_database_top.cgi?stn=F6381
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Thanks for why and now know where to look if happens again.
Was clear and calm here so wonder if nearby stations being colder caused, or maybe too many cfm in my shield.
Will see if happens again. Hope not as then may need to figure out how to throttle back 24cfm
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Will see if happens again. Hope not as then may need to figure out how to throttle back 24cfm
I run my 60CFM 24/7 without dialing back anything and never see your problem. It ain't that.
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Maybe sht bad?
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Nope.
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As I scrutinize your obs further, I really don't see any problem on your end, none. The graduations are fine. Perhaps Meso's jacked or your neighbors are really jacked. Up to you to find out.
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Thanks. Was a strange evening with calm winds to start and quick falling Temps. Then winds picked up sw off lake Erie and shot temp up 9 degrees in a little over hr. Could be just function of quicker response time.
Will enjoy and see how goes over larger sample over long run.
Thanks again
Frank
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Yeah those spikes are not from the fan moving too much air it's something else. Did sprinklers or something come on?
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Hi. No sprinklers here this time of year as is fall up in Buffalo, NY. Thanks for suggestion.
Will keep eye on it and see if happens again this evening when sun sets.
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The welded core with open plates works best with FARS. They really aren't that expensive without the electronics attached. I've tried the open core Dfars and it doesn't work as well being wide open. On the inlet screencap, you can cover it with filter material and slip it back on. I use silk 100 thread and leave the filter off the sensor. I don't know if it's needed but have always used the insulator too.
Scaled has an exploited view of what is needed. Of course, you don't want anything to do with solar or batteries.
https://www.scaledinstruments.com/wp-content/uploads/2020/12/24hr_fars_Exploded_Diagram.pdf
Here is the welded core. On backorder, it looks like: https://www.scaledinstruments.com/shop/davis-instruments/parts/vantage-pro2-parts/radiation-shield-parts/davis-7345-029-vantage-pro2-24-hr-spars-welded-core/
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Thanks, I used that schematic from Scaled and that is the setup I have (less solar panel and batteries).
May use solar in the summer to avoid extension cord across yard when mowing but that is for another day.
Agree not sure if need the insulator, but installed as diagram called for.
Figured with moving air and the open plates already had plenty of insulation so interesting you mentioned.
Would be curious if anyone is running without the insulator?
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Thanks, I used that schematic from Scaled and that is the setup I have (less solar panel and batteries).
May use solar in the summer to avoid extension cord across yard when mowing but that is for another day.
Agree not sure if need the insulator, but installed as diagram called for.
Figured with moving air and the open plates already had plenty of insulation so interesting you mentioned.
Would be curious if anyone is running without the insulator?
Oh good, I thought by post #26 this was a dfars and was saying oh no.
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You need the insulator, look at the inside and it has ridges that create an air gap between the sensor housing and the insulator, it is another air intake tube that scrubs any heat away from the sensor chamber.
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Would be curious if anyone is running without the insulator?
Agree with Jerry. The insulator is there for a reason. Just as an FYI, the 24hr shield is patented so I figure they know what they're doing.
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That's right Jerry forgot about that. Another area to scrub heat away from the sensor is the air gap around the insulator.
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Thanks guys for explaining the mechanics of the shield.
I am very happy with the way been running so far.
Much calmer wind day today with mix of sun and clouds throughout the day.
Has been very stable temp throughout.
I have the SF2 Cap installed as have since setup station 2 years ago.
Few more quality suspect points today on Mesowest because of dewpoint variance again today, but am starting to suspect is function of data quality around me.
Not going to worry about it as know am running shield to build specs :grin:
Thanks again
Frank
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Not going to worry about it as know am running shield to build specs :grin:
Good. QC is a tool, not an end-all-be-all. Nobody knows your data better than you.