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$5-9 Dew Controller 8amp

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#1 mega256

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Posted 10 December 2012 - 12:53 AM

This is cheap and will handle 8 amps !=96 watts..
For $5-9..

http://www.amazon.co...s/dp/B003L4K...

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#2 korborh

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Posted 10 December 2012 - 01:16 AM

Cool! I wonder if it is really rated at 8A. Dew strip will use much less unless there are several of them tied in parallel.
I may just get it to take it apart and check the safety aspect of its design.

#3 Silicon Owl

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Posted 10 December 2012 - 03:29 AM

From the closeup of the circuit board it looks to be just an oscillator and a switch transistor, no attempt to filter or smooth the current. It should work well on a resistive load like a dew heater. Not so sure about using it on some LED's!

My handmade dew heater controller is much the same... http://darkerview.co...rdpress/?p=3947

#4 korborh

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Posted 10 December 2012 - 09:53 AM

Very nice Andrew! Your dew heater looks really well made and the case is pretty cool.
Mine is much simpler and not so finished looking but works. I needed to push only 1.5A so just used a LM317 with pot and input from old laptop charger.

#5 Don Trinko

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Posted 10 December 2012 - 10:22 AM

very interesting, I put it on my wish list for further consideration. Don T.

#6 Silicon Owl

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Posted 12 December 2012 - 06:46 PM

An LM317 would work, but is quite inefficient. A lot of your battery power is wasted in the regulator. The Huub Willems/Chris Heapy design is very simple, not much more difficult than the LM317, and nearly all of your battery power is dumped into the dew heater, not dissipated in the controller.

http://www.backyard-.../dewheater.html

#7 korborh

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Posted 12 December 2012 - 09:10 PM

The power dissipation will depend on the input/output voltage differential. In my case it is <10W. With the tin can easily dissipating it, I don't think about it much....as long as it works. Its wall powered so I did not care much about efficiency. I wanted to avoid noisy switching PWM for this ultra-simple application.






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