Author Topic: Happy medium for heated rain gauge  (Read 1659 times)

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Offline WA7FWF

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Happy medium for heated rain gauge
« on: December 31, 2017, 01:41:06 PM »
So I added a heater to my rainwise rain gauge. I picked a temp switch that I thought would be low enough not to evaporate too much, and so far it is working well but it may be a little too cool as it can take hours after the snow stops to finally melt everything, on the plus side so far it looks like I'm losing very little to evaporation. The heater kicks on at around 34 and shuts off around 54 on the inside, the plastic funnel surface varies greatly depending on outside temp and wind speed but stays just above freezing by a few degrees. I'm thinking it's better to spread out the reporting vs quick but losing tons to evaporation. [ You are not allowed to view attachments ]  [ You are not allowed to view attachments ]

Offline ValentineWeather

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Re: Happy medium for heated rain gauge
« Reply #1 on: December 31, 2017, 02:59:45 PM »
That may be the key melt slowly. Problem I see is overflowing bucket with snow. My TE heater is pathetic with the dry snow 20:1 moisture ratio around 60% evaporation loss vs manual readings.
Randy

Offline WA7FWF

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Re: Happy medium for heated rain gauge
« Reply #2 on: January 01, 2018, 11:21:39 AM »
  I have been watching it to see if it would overflow and so far it has not been a issue, it looks like it melts quicker the more snow it has in it and I'm thinking the snow acts like a blanket to keep the colder air out. When it is below freezing and windy with little snow inside is when it really slows down.

  Your TE has a aluminum catcher doesn't it? how about attaching a thermistor to it and using a temp controller to keep it just a little above freezing? does the heater run on 120 Vac? maybe a variac and lower the voltage going to it might also help?

Offline ValentineWeather

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Re: Happy medium for heated rain gauge
« Reply #3 on: January 01, 2018, 01:46:41 PM »


  Your TE has a aluminum catcher doesn't it? how about attaching a thermistor to it and using a temp controller to keep it just a little above freezing? does the heater run on 120 Vac? maybe a variac and lower the voltage going to it might also help?

Yes it has a heated material that's wrapped around the funnel area it does cycle on and off problem I guess is it just gets to warm between cycles. I may do something with it next year. 
Randy

Offline ggsteve

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Re: Happy medium for heated rain gauge
« Reply #4 on: January 09, 2018, 02:47:31 PM »
So I added a heater to my rainwise rain gauge. I picked a temp switch that I thought would be low enough not to evaporate too much, and so far it is working well but it may be a little too cool as it can take hours after the snow stops to finally melt everything, on the plus side so far it looks like I'm losing very little to evaporation. The heater kicks on at around 34 and shuts off around 54 on the inside, the plastic funnel surface varies greatly depending on outside temp and wind speed but stays just above freezing by a few degrees. I'm thinking it's better to spread out the reporting vs quick but losing tons to evaporation. [ You are not allowed to view attachments ]  [ You are not allowed to view attachments ]

Very nice work!  Can you provide some details on that heater?  Was it off the shelf or DIY?  I am very interested in heating my Rainwise tipper.
« Last Edit: January 09, 2018, 02:49:22 PM by ggsteve »

Offline ValentineWeather

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Re: Happy medium for heated rain gauge
« Reply #5 on: January 22, 2018, 01:55:49 PM »
Well heater in the TE raingauge did well with warmer snow event. It was only off by 1 tip in .35 snow. Temperature mainly between 27-31 during event.  So all those bad things of evaporation seem to mainly occur with single digit temperatures and snow.
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Randy

Offline WA7FWF

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Re: Happy medium for heated rain gauge
« Reply #6 on: March 21, 2018, 11:10:52 PM »
Sorry ggsteve, for some reason I missed your question, total DIY, heatsink was something I had laying around, the resistor is a 24 ohm 50W unit mounted to the heatsink with heatsink compound and most expensive part is the temp sensor mounted about one inch above the bottom (2455RBV84690007 Honeywell Thermostats) about $25 closes at 1.7C opens at 12.8C, I feed 24vdc out to it with 18awg zipcord and a little insulation inside to hold the heat.

Offline Bashy

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Re: Happy medium for heated rain gauge
« Reply #7 on: March 23, 2018, 04:02:53 AM »
I just use a 12v 5w bulb with a thermostat switch, even made my thermal layer using 1 sheet of bubble wrap sandwiched between 2 sheets of foil, works great for my needs :)
Kind regards
Bashy