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Dew Heater differences?

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#1 Footbag

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Posted 03 April 2013 - 08:28 AM

Are there any real differences between the basic dew controllers available? Are they all the same in regards to power requirements, temp regulation, other capabilities?

EDIT: Since I usually don't get dewed out until 1-2AM, I'll assume that they only draw current when needed and not the whole night. Correct?

Looking at AstroZap, Thousand Oaks, Dew Not.

#2 rmollise

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Posted 03 April 2013 - 09:19 AM

Nope. Not correct in the case of "basic" controllers. Their controllers don't know anything about temperature. Advance the knob, the power stays on longer, etc. For temperature control where no current is applied until you need it, you want a DewBuster or one of the temperature regulated Kendricks. ;)

#3 Footbag

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Posted 03 April 2013 - 10:58 AM

Nope. Not correct in the case of "basic" controllers. Their controllers don't know anything about temperature. Advance the knob, the power stays on longer, etc. For temperature control where no current is applied until you need it, you want a DewBuster or one of the temperature regulated Kendricks. ;)


Thanks. That's one of the things I wasn't understanding.

#4 wolfman_4_ever

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Posted 04 April 2013 - 02:26 PM

U want to turn the controller on early. U want to prevent dew not go into emergency dew removal.

#5 Footbag

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Posted 04 April 2013 - 02:30 PM

U want to turn the controller on early. U want to prevent dew not go into emergency dew removal.


If I typically get dewed out at 1am, it seems like a waste of batteries to run it much earlier then that. I'm guessing that's what the regulated ones do, only turn it on when reaching the dew point.

#6 ubermick

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Posted 04 April 2013 - 02:42 PM

If you KNOW you get dewed out starting at one, just set your watch or phone alarm to go off at 12:30, and pop your dew straps on. Easy peasy.

I just built a dew controller and set of straps using 12v PWM controllers from Amazon ($7.50 each shipped via Amazon Prime) but am now pondering a few PIDs...

#7 Footbag

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Posted 04 April 2013 - 02:58 PM

If you KNOW you get dewed out starting at one, just set your watch or phone alarm to go off at 12:30, and pop your dew straps on. Easy peasy.

I just built a dew controller and set of straps using 12v PWM controllers from Amazon ($7.50 each shipped via Amazon Prime) but am now pondering a few PIDs...


Well, of course that depends on the weather, but it's typically 1am. I'd probably leave the straps on and just turn on the controller.

I was considering building one myself, but I'd want it to look good. I think the effort and money I'd put into it, would make it more expensive then buying one.

#8 rmollise

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Posted 05 April 2013 - 06:50 AM

U want to turn the controller on early. U want to prevent dew not go into emergency dew removal.


If I typically get dewed out at 1am, it seems like a waste of batteries to run it much earlier then that. I'm guessing that's what the regulated ones do, only turn it on when reaching the dew point.


No. What they allow you to do is set the temperature a given amount above _ambient_. 5 or 10 degrees will do it. Your idea of turning on your dew heater at 1 a.m. will not work unless you live in the desert. The idea is to apply gentle heat from the beginning of the evening to keep the corrector dry. I suspect you've never seen one in person, but the amount of heat they put out is low. You can barely feel the heater strip is warm. I wouldn't worry too much about a battery. Even a basic unit will run all night on a 17ah jump start battery. ;)

#9 Footbag

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Posted 05 April 2013 - 05:35 PM

Thanks Rod. I hope to see and buy my first at NEAF.

My big concern is that I'd rather not have a seperate battery for the heaters. I have a 28ah battery that runs my mount, laptop and camera. I may be asking too much.

#10 fmhill

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Posted 05 April 2013 - 06:00 PM

Thanks Rod. I hope to see and buy my first at NEAF.

My big concern is that I'd rather not have a seperate battery for the heaters. I have a 28ah battery that runs my mount, laptop and camera. I may be asking too much.


I run 2 dew heater bands, one on a 127mm APO (5") refractor, the other on a 80mm guide scope. I use a Thousand Oaks controller and being in a heavy dew area, I start them about dusk and run them to about 3 AM and a 28 Ah battery does that and runs the mount and a 4 port USB HUB fine. (I have separate power for the imaging camera)...






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