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Any inexpensive alternatives to power my dew strip?

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32 replies to this topic

#1 Ballyhoo

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Posted 24 February 2021 - 07:21 PM

OPT is just referring me to the $329 Pegasus console.

 

Must be something cheap to connect it to a 12 volt adapter.

 

https://optcorp.com/...heaters#reviews



#2 PNW

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Posted 24 February 2021 - 07:28 PM

I use a PWM box I picked up for a couple of bucks. It's sold as a dimmer for LED lights. You gotta kind of hard wire it to 12v and an RCA jack. I also put an LED indicator light on the output side to show how much power it's sending out. Total cost: $3 for the dimmer and $4 for the LED. I had an old RCA jack and use alligator clips for power.


Edited by PNW, 24 February 2021 - 07:32 PM.

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#3 3snows

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Posted 24 February 2021 - 07:30 PM

OPT also sells this one which I use.

 

https://optcorp.com/...b1f17e3b406e0e4


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#4 t-ara-fan

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Posted 24 February 2021 - 07:30 PM

Kendrick makes a "Standard Dual Channel" controller https://www.kendrick...nnel Controller

 

It is pretty good UNLESS you use batteries for power.  If the battery drops below 11.6V the dew controller shuts off to "save the battery". But it can ruin the evening.

 

I sold it, and built a PWM like PNW mentioned.

 

Astrozap also makes controllers.


Edited by t-ara-fan, 24 February 2021 - 07:32 PM.


#5 Ballyhoo

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Posted 24 February 2021 - 07:35 PM

is there something that could just connect it to go to a 12volt or cigarettes' type charger?  I guess I did not want to spend $ hundreds to do something so simple as generate some heat on the outside of my OTA. 

 

although #3 is not too bad. 


Edited by Ballyhoo, 24 February 2021 - 07:35 PM.


#6 cytan299

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Posted 24 February 2021 - 07:40 PM

is there something that could just connect it to go to a 12volt or cigarettes' type charger?  I guess I did not want to spend $ hundreds to do something so simple as generate some heat on the outside of my OTA. 

 

although #3 is not too bad. 

I use this:

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

FYI, its case is metal and not plastic.

 

IMO, dew heater controllers cost too much just because they are labeled "dew heater". LED light dimmers do exactly the same thing and cost 4 to 5 times less.

 

cytan


Edited by cytan299, 24 February 2021 - 07:41 PM.

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#7 ButterFly

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Posted 24 February 2021 - 07:42 PM

Those low voltage cutoffs are disappearing lately.  If I had to buy a new truck battery five years earlier, so be it if it means more of a good night.

 

Pegasus also makes a bare bones PWM controller, with no short circuit protection.  There is also a seller in the classifieds who makes bare bones controllers with short protection.  These are all much less than $100.

 

You really don't need a controller though.  They help distribute and control power.  You can do that yourself if you wire your own cable.



#8 Ballyhoo

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Posted 24 February 2021 - 07:42 PM

I use this:

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

IMO, dew heater controllers cost too much just because they are labeled "dew heater". LED light dimmers do exactly the same thing and cost 4 to 5 times less.

 

cytan

that is awesome. The primalucelab dew heater has a male connecter. I probably would have to find out how to connect it to this dimmer product. Maybe direct in.


Edited by Ballyhoo, 24 February 2021 - 07:43 PM.


#9 Mike G.

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Posted 24 February 2021 - 07:43 PM

I built my own 3 channel with 12v pass through using a 3 channel PWM controller (ebay), some red LEDs I had laying around, a couple panel mount connectors and a project box.  total cost was $31 a few years ago. still works great, acts as a 12v source (once I attach either a battery or power brick) for my mount and is small and light enough to velcro to the legs of my mounts.  not difficult if you have even modest soldering skills.  go for it!



#10 Ballyhoo

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Posted 24 February 2021 - 07:44 PM

This is what makes CN great. $14 instead of $100. :)


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#11 Ballyhoo

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Posted 24 February 2021 - 07:45 PM

I built my own 3 channel with 12v pass through using a 3 channel PWM controller (ebay), some red LEDs I had laying around, a couple panel mount connectors and a project box.  total cost was $31 a few years ago. still works great, acts as a 12v source (once I attach either a battery or power brick) for my mount and is small and light enough to velcro to the legs of my mounts.  not difficult if you have even modest soldering skills.  go for it!

sounds terrific, If you put your "how to" on Youtube I bet you would help a lot of people.



#12 Mike G.

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Posted 24 February 2021 - 07:46 PM

sounds terrific, If you put your "how to" on Youtube I bet you would help a lot of people.

CN is the ONLY social media I use.  period.  sorry.


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#13 barbarosa

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Posted 24 February 2021 - 07:47 PM

My solution (some experimentation, measurement and Ohm's Law required) but my 95% solution was to run the dew heaters continuously at 12VDC from a 12VDC adapter. Dew is a serious problem here. Depending on the mix of scopes current draw is regulated by connecting two of the heaters in series. Two settings- connected and disconnected.

 

Never did get around to ordering the PWM controller from Amazon.


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#14 RogerM

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Posted 24 February 2021 - 07:51 PM

I use this:

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

FYI, its case is metal and not plastic.

 

IMO, dew heater controllers cost too much just because they are labeled "dew heater". LED light dimmers do exactly the same thing and cost 4 to 5 times less.

 

cytan

+1 on that controller.  For the output you can easily wire in this RCA adapter and use this adapter for the 12V input.


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#15 cytan299

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Posted 24 February 2021 - 07:53 PM

My solution (some experimentation, measurement and Ohm's Law required) but my 95% solution was to run the dew heaters continuously at 12VDC from a 12VDC adapter. Dew is a serious problem here. Depending on the mix of scopes current draw is regulated by connecting two of the heaters in series. Two settings- connected and disconnected.

 

Never did get around to ordering the PWM controller from Amazon.

Ummmm, you should wire the dew strips in *parallel* and not in series. Having this strips in parallel will ensure that 12 V is across each strap. For the 2" eyepiece dew heatr strap that I have, its resistance is 40 ohms (you'll have to measure the resistance of your strap). So the current required for this strip is V/R = 12/40 = 0.3 A (max if running full blast). And with the LED dimmer that I bought, it is rated at 3 A and so I can string 10 of these 2" eyepiece dew straps in parallel smile.gif

 

cytan


Edited by cytan299, 24 February 2021 - 07:55 PM.


#16 WadeH237

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Posted 24 February 2021 - 08:37 PM

I guess I did not want to spend $ hundreds to do something so simple as generate some heat on the outside of my OTA. 

To be fair, that is not the reason for a dew controller.

 

If all you want to do is to make heat, then applying a fixed 12 volts is fine.  But what you really want to do, is to apply just enough heat to keep the optics clear.  Applying more heat not only wastes power (which can be important if you are running from battery), it also has the potential to create effects that degrade the image.

 

There are a couple of strategies for managing power to dew heaters.

 

Personally, I use the Ron Keating DewBuster for my visual setups.  It uses two different temperature sensors.  One of them is on the OTA and one is exposed to the open air.  The controller compares the two readings and applies just enough power to raise the OTA heat to a certain amount above the ambient air temperature.  You can dial in the desired temperature differential between zero and 20 degrees C.  I find that on most nights, a 5C delta keeps the optics clear just fine.  On damp nights, I dial in 10 degrees.  And if the OTA actually stars accumulating dew, I temporarily dial it up to 20C long enough to clear the OTA, and then dial it back down.

 

The Pegasus Astro system is a bit different.  I measures temperature and humidity to calculate the dew point.  It then uses the dew point and temperature information to determine the power needed for the dew heater.  I don't know the details of their algorithm, but I can say that it works quite well.

 

Both of these systems keep the power consumption far lower than they would be than if you just applied continuous current to the dew heater.

 

There is an in-between strategy that just uses a simple PWM controller to vary the current supplied to the dew heater.  In this case, it's up to the user to manually adjust the current as needed.

 

As an imager who frequently runs on battery power, I find a good dew controller to be a good investment.  Yes, I spent a few hundred dollars for each of my controllers.  But I don't worry about dew, ever.


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#17 Migwan

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Posted 24 February 2021 - 08:55 PM

that is awesome. The primalucelab dew heater has a male connecter. I probably would have to find out how to connect it to this dimmer product. Maybe direct in.

 Some female RCA choices.    The local big box has some you can solder, but the ones with wires already attached are a lot less fuss.  

 

I use a RBG Led dimmer switch to a dew strip for each scope and then the third channel to run two eyepiece strips in parallel.  Works great.   For a single channel the one Cytel lists is very good.  

 

jd



#18 Ballyhoo

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Posted 24 February 2021 - 11:05 PM

 Some female RCA choices.    The local big box has some you can solder, but the ones with wires already attached are a lot less fuss.  

 

I use a RBG Led dimmer switch to a dew strip for each scope and then the third channel to run two eyepiece strips in parallel.  Works great.   For a single channel the one Cytel lists is very good.  

 

jd

thanks, what is a cytel list? Also if you do not mind me asking, how do you power the dimmer? 



#19 Migwan

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Posted 25 February 2021 - 06:10 PM

thanks, what is a cytel list? Also if you do not mind me asking, how do you power the dimmer? 

Meant Cynten from post #6.  

 

My battery pack has a 2.5 female jack so my wiring harness (CPC, Fans & dew control) has a 2.5 male DC jack wired it.   Search

 

There are also 2.1mm DC jacks, just in case.    Search

 

jd



#20 Migwan

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Posted 25 February 2021 - 06:57 PM

1,000 word.  The jack hanging at bottom plugs into battery pack, which I set on the deck.  The inline switch is to the fans.  

 

jd

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#21 Ballyhoo

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Posted 27 February 2021 - 05:48 PM

I have these two items, the dimmer and th 12 volt cigarettes' type ligther but I am not 100% sure what connector to purchase, I presume the femal RCA jack?  (it is times like this when  I miss radioshack.

 

I have these now:

 

https://www.amazon.c...1?ie=UTF8&psc=1

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

Should I get this to connect them?

 

https://www.ebay.com...CLK|clp:2334524


Edited by Ballyhoo, 27 February 2021 - 05:49 PM.


#22 cytan299

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Posted 27 February 2021 - 07:12 PM

Hi Ballyhoo,

 

   The last connector is incorrect. It needs to be a 2.1 mm plug and not 2.5 mm because the plug that the led dimmer comes with

 

*********

 

DC Female Power Cord Specification:
● Connector: 5.5 * 2.1mm
● Length: 30cm

 

*********

 

You can just buy a plug from jameco and solder it onto the pigtails of your cigarette lighter:

 

https://www.jameco.c...ug_2230344.html

 

I've found similar plugs on amazon, but the quality is not that great.

 

cytan

 

P.S. I don't know why the amazon ad calls it a female plug. 


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#23 Ballyhoo

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Posted 27 February 2021 - 11:21 PM

Hi Ballyhoo,

 

   The last connector is incorrect. It needs to be a 2.1 mm plug and not 2.5 mm because the plug that the led dimmer comes with

 

*********

 

DC Female Power Cord Specification:
● Connector: 5.5 * 2.1mm
● Length: 30cm

 

*********

 

You can just buy a plug from jameco and solder it onto the pigtails of your cigarette lighter:

 

https://www.jameco.c...ug_2230344.html

 

I've found similar plugs on amazon, but the quality is not that great.

 

cytan

 

P.S. I don't know why the amazon ad calls it a female plug. 

is it easy to solder the little copper wires to the female connecter?  I am trying to picture whether the connector will have wiring to it which would be simple to connect, otherwise I am not sure how that works.  The description is a barrel plug  so I am not sure how much there will be to work with. 



#24 KenS

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Posted 27 February 2021 - 11:34 PM

You can easily get plugs with screw terminals e.g. these


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#25 cytan299

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Posted 28 February 2021 - 11:00 AM

is it easy to solder the little copper wires to the female connecter?  I am trying to picture whether the connector will have wiring to it which would be simple to connect, otherwise I am not sure how that works.  The description is a barrel plug  so I am not sure how much there will be to work with. 

Ok, maybe my suggestion isn’t the best if you are not that experienced with soldering. So, I’d recommend these:

 

https://www.amazon.c...,aps,192&sr=8-4

 

then it's a cinch to solder.

 

I’ve used KenS suggestion before and they don’t work too well because of the thinness of the wire and the weight of the plug. Eventually, the wires fray and the connection fails.

 

cytan




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