Author Topic: PWS for Rachio?  (Read 1130 times)

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Offline redcoat

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PWS for Rachio?
« on: April 24, 2023, 08:25:08 PM »
hi everyone,

Complete newbie here.

I just purchased a Rachio 3 irrigation controller (I have 11 zones). There are a couple of WUnderground stations near me, but their rain counts are off by ~20% so I'd like to set up my own. I am only really interested in using it as it relates to ET, to allow Rachio to adjust watering times appropriately.

Thinking of spending ~$200 if I can get something ok for that amount? Found this on Amazon: https://www.amazon.com/Ambient-Weather-WiFi-Station/dp/B01N5TEHLI.

Would I get a lot more by stretching to $300?

cheers

David

Offline weatherdoc

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Re: PWS for Rachio?
« Reply #1 on: April 25, 2023, 07:43:17 AM »
I've been using Rachio for 5 years with my weather station (Davis VP2). Automated rain measurements are not as accurate as a manual gauge, especially during heavy rain. With heavy rain, my rain gauge can be up to 15% lower than my manual gauge - that's a fact for most weather stations because the mechanism (tipping bucket or tipping spoon) can't keep up with the rainfall rate. That said, Rachio will also "decide" whether to water based on the forecast, which can be a problem, especially in the summer due to the more scattered nature of showers and thunderstorms. If the forecast calls for a relatively high chance of rain in the form of showers and thunderstorms, Rachio will not water your lawn in anticipation of the rain. More often than not, it will not rain at my house with those hit and miss storms and I will have to water manually anyway. In the end, having an automated rain gauge in your own yard to trigger your Rachio is a good idea, but it's not foolproof.

Offline SteveFitz1

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Re: PWS for Rachio?
« Reply #2 on: April 25, 2023, 09:53:41 AM »
I'll take the opposing view of Weatherdoc.

I've had my Rachio for about 5 years as well and love it. I have my Rachio use only my weather station (Davis VP2). My VP2 does an excellent job of measuring rainfall whether it's just a drizzle or a downpour. I have Cocorahs gauge right next to it so I'm able to compare the totals on a regular basis. And they are always extremely close, if not right on. I don't recall Rachio skipping watering very often due to missed rain forecasts. In fact, I don't think I've had to water manually more than a half dozen times since I've had the Rachio.

I'm a big fan of the Rachio. I've sold several neighbors on getting one. In fact, they just point to my weather station for their Rachio to use.

Steve

Offline PaulMy

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Re: PWS for Rachio?
« Reply #3 on: April 25, 2023, 10:29:58 AM »
I don't have Rachio but do have the Hydrawise/Hunter system controller and have selected my WU station as well as some other local WU contributors in the Weather Station settings.  As Steve mentioned the Davis VP2 is very close and mostly identical to my manual CoCoRaHS but I have less confidence in WU or its forecast as it relates directly to my location so I have added the Hunter RainClick sensor to the controller.  The rain sensor makes sure the irrigation is stopped when it actually rains, and doesn't restart until the sensor is actually dry (very important for our extremely high water/sewer-surcharge rates).


Enjoy,
Paul

Offline weatherdoc

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Re: PWS for Rachio?
« Reply #4 on: April 25, 2023, 03:24:51 PM »
My CoCoRaHS is next to my Davis as well. I agree with SteveFitz1 that most of the time the Daivs and CoCoRaHS measurements are very close - typically within 0.01" - except for high rainfall rates. Thunderstorm type rain rates are typically about 15% low with the Davis. I found the same to be true with my first Davis that I had in Florida for 8 years. I kept detailed records of Davis versus CoCoRaHs for about 6 years and with rainfall rates about 1" per hour or more, the tipping bucket couldn't keep up.

As far as missed rain forecasts, I should qualify the issue where I live. In northern Virginia, I live about 5 miles east of the Bull Run Mountains at the eastern edge of the Blue Ridge Mountains, which are 20 miles west of my house. The Bull Run Mountains are about 700 ft in elevation and the Blue Ridge about 2000 ft. That's just enough to cause thunderstorms moving eastward across the mountains to dissipate in my vicinity due to downslope and drying and often to reform about 5-10 miles east of my house. Yet the Rachio will not water because the forecast is for thunderstorms, but the forecast is not fine scale enough to recognize the microclimate just east of the mountains.

I do rely on my Rachio and I would recommend having your own weather station to support it. Many of my neighbors rely on my Davis for their Rachio.

I do have a question for redcoat: how do you know a couple of Wunderground stations near you are off by ~20%?

Offline redcoat

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Re: PWS for Rachio?
« Reply #5 on: April 25, 2023, 05:01:16 PM »
Thanks for the responses everyone!

the Davis is more than I was hoping to spend. Not sure if I'd need something extra to sync the data, too?

What would I be missing out on if I went with the one I linked?

I do have a question for redcoat: how do you know a couple of Wunderground stations near you are off by ~20%?
I have 2 very close to me and the rainful was 20% different. I guess it could be accurate, but didn't smell right given the extent of the storm we had.

Offline SteveFitz1

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Re: PWS for Rachio?
« Reply #6 on: April 25, 2023, 05:20:33 PM »
Whatever station you choose, I'd definitely recommend also getting a CocoRahs rain gauge and put near the weather station. That will always give you a very accurate source for comparison to whatever your weather station is giving you. Then you'll know for sure how well the weather station is performing.

Offline weatherdoc

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Re: PWS for Rachio?
« Reply #7 on: April 25, 2023, 05:59:45 PM »
Quote
I have 2 very close to me and the rainful was 20% different. I guess it could be accurate, but didn't smell right given the extent of the storm we had.

Ah, okay, looking at two different stations, not comparing it to a manual gauge at your house, I misunderstood. If you look at the attached image (rdu-cocorahs.png) from the Raleigh area on 23 April, you can see a wide range of rain totals, some rain gauges are fairly close together. Look at sw-rdu-cocorahs.png - those two stations are 28% different and 1.4 miles apart. So, it depends how far the stations are from each other. With this type of storm that had embedded convection, 20% difference between the stations is possible.

I agree with SteveFitz1 - having a CoCoRaHs gauge next to your weather station will help verify the weather station gauge's accuracy. No need to pay for a Davis just to make sure your irrigation system is running on the right days!

BTW, I went to NC State for my MS and PhD in Atmospheric Sciences and lived in North Raleigh and also near Rolesville off of Rt 401.

Offline redcoat

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Re: PWS for Rachio?
« Reply #8 on: April 25, 2023, 07:44:18 PM »
Sounds good.

Silly question - is there a way to empty a CoCoRaHs without just turning it upside down? Does it come off easily?

I'm thinking of putting the PWS on the roof - is it ok to have the CoCoRaHs somewhere nearby at ground level?

Offline SteveFitz1

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Re: PWS for Rachio?
« Reply #9 on: April 25, 2023, 08:51:54 PM »
You have to turn it over to drain it. You lift the funnel off and pour out the contents of the inner tube and outer tube if there's rain in it.

I have mine adjacent to my VP2 sitting about 6 feet off the ground.

Steve

Offline redcoat

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Re: PWS for Rachio?
« Reply #10 on: April 25, 2023, 09:11:57 PM »
Ok. Hopefully it comes off the post easily  :lol:

Thinking of putting the PWS on the top right point of garage. Would that be ok? Marked on the attached photos. Any other location better? Trying to balance height with accessibility!

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Offline weatherdoc

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Re: PWS for Rachio?
« Reply #11 on: April 26, 2023, 06:59:25 AM »
The wind will be blocked by your house, but it looks like you have a nice wooded lot making it difficult to locate a good spot for measuring the winds anyway. If your goal is to mainly use your station to measure rainfall to support your Rachio then this spot is fine. The closer to the ground the more accurate the rain measurement will be - typically 6ft off the ground. I don't believe you'd see a noticeable difference in rainfall accuracy between 6ft above the ground and the peak above your garage. Finding a good spot at a residence is always a challenge. My temperature, humidity and rain sensors are 4.5 ft off the ground, but my wind sensors are only 15 ft off the ground (30 ft is ideal) and partially blocked by a Crepe Myrtle tree (my wife won't let me cut it down!).

Where would you put your CoCoRaHS gauge? An open spot with no trees above, about 4-6ft off the ground, would be best so you can easily access it to empty it.

Offline redcoat

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Re: PWS for Rachio?
« Reply #12 on: April 26, 2023, 09:52:49 AM »
I could try and put it on a different peak if it will be more accurate? Either the one above the one I suggested, or the front one:

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Alternatively we have a septic field where I could put it closer to the ground - itís pretty sheltered though with a channel through the trees:

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Offline weatherdoc

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Re: PWS for Rachio?
« Reply #13 on: April 26, 2023, 12:50:36 PM »
Either peak would be better for more accurate winds, but there's always the consideration for the aesthetics of your home and the risk of working up high. The center of your backyard might work - looks like the tree canopy doesn't cover the entire backyard. In Florida, I put a 4x4 post about 3ft in the ground and 6ft above ground and mounted the sensors and CoCoRaHS gauge on it. I attached a 10ft galvanized pole to it for the wind sensors. Here in Virginia, I attached the sensors, CoCoRaHS gauge, and galvanized pole to my fence.



In this photo looking south, you can see how the Crepe Myrtle tree disrupts the wind on the east side of the wind sensors - especially when there are leaves on the tree.

Offline BoDuke

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Re: PWS for Rachio?
« Reply #14 on: April 26, 2023, 02:43:44 PM »
Keep in mind there is maintenance involved with the rain gauge, keeping the tipping spoon clean and the funnel free from obstructions.  All-in-one weather stations have some advantages and disadvantages compared with separate sensors.  An all-in-one that has solar power means fewer batteries and longer life from those batteries but you lose the ability to separately position the sensors for their best accuracy.  Separate wind/rain/temp & humidity sensors allows for better positioning but you have more batteries and few of those sensors have solar panels.  Making sure the radio frequency signals are received by the console/gateway from the sensor(s) is another consideration.

Since you have quite a number of tall trees around, I'm not sure you'll get very accurate wind readings.  If you're not concerned about the accuracy of the wind direction and speed, then position the weather station for the best accuracy of the rain gauge.  I like to imagine a strong rain being driven at an angle by the wind when deciding on a location.  If you put it too close to trees, structures, or other similar obstacles, the rain may not reach the funnel and get measured.  At my house, the best place for my weather station would be near the street but that is not ideal or allowed for numerous reasons so it's in a less-than-ideal location in the back yard.  Positioning a weather station or sensors is almost always an exercise of compromises.

 

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