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Where to get flexible 2 core power cable?

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#26 johndgaul

johndgaul

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Posted 20 January 2013 - 06:48 PM

Chris, that looks great! Thanks for posting - and Anderson Powerpoles too - I like your style :)

Say 0.3 + 0.2 = ~0.5 ohm on a 10ft run, so might be ~0.2 ohm on a 4 ft run from dew heater controller to dew heater strip, assuming negligible resistance at the electrical contacts.

As an example, a Kendrick Astro 5" optic "Premium" dew heater is specified to draw 1.2A. Note that the Kendrick Firefly strips draw half the current of the "Premium" stips (and perhaps other strips like the Dew Nots?). I would assume a dew heater controller uses pulse width modulation to adjust the output, so 12V or 0V is put across the ouput, giving 1.2A or 0A. Voltage drop across a 0.2 ohm cable would be V = IR = 1.2A * 0.2 ohm = ~ 0.2V. Another way of looking at it would be 0.2V / 12 V = ~2% power loss in the cable (P = VI, and I is the same in cable and heater strip). This isn't much, and might just keep the cable flexible :) Fine!



from Kendrick Astro, specs for the "Premium" strips:

Item No Heater WattageAmperageHeater DimensioHeater Dimensions
Metric* Imperial*
2003Telrad Heater 6 0.4 50 x 90 mm 2" x 3.5"
2003-RDRed Dot Finder Heater 2.5 0.2 Press fit Press fit
2004.965" Eyepiece Heater 2.5 0.2 16 x 75 mm 1/2" x 3"
20051.25" Eyepiece Heater 3 0.2 16 x 125 mm 1/2" x 5"
20062" Eyepiece Heater 4 0.3 16 x 175 mm 1/2" x 7"
2006-L DEW-Minator Large Eyepiece Heater 10 0.8 75 x 205 mm 3" x 8"
20073" Optic Heater 10 0.8 25 x 280 mm 1" x 11"
20084" Optic Heater 11 0.9 25 x 370 mm 1" x 14.5"
20095" Optic Heater 15 1.2 25 x 460 mm 1" x 18"
20106" Optic Heater 17.5 1.4 25 x 560 mm 1" x 22"
20117/8" Optic Heater 20 1.6 25 x 660 mm 1" x 26"
20129/10" Optic Heater 25 2 25 x 890 mm 1" x 35"
201311" Optic Heater 28 2.3 25 x 965 mm 1" x 38"
201412" Optic Heater 33 2.6 25 x 1115 mm 1" x 44"
201514/16" Optic Heater 52 4.1 25 x 1270 mm 1" x 50"
2005-B1Bino-viewer Heaters for eyepieces up to 1.5 in 5 0.4 16 x 125 mm 1/2" x 5"
2005-B2Bino-viewer Heaters for eyepieces over 1.5 inc 8 0.6 16 x 175 mm 1/2" x 7"
2016Secondary Mirror heater for Newtonian secondar 2.5 0.2 44 x 66 mm elli1.75" x 2.6" ellipse
2017Secondary Mirror heater for Newtonian secondar 4 0.3 50 x 90 mm 2.5" x 3.625"ellipse
2018Secondary Mirror heater for Newtonian secondar 9 0.7 50 x 90 mm 3.75"x5.50"ellipse
2019Electronic Hand Control Pad Heater 10 0.8 57mm x 165mm 2.25" x 6.5"
2020Eyepiece Box Heater 10 0.8 57mm x 165mm 2.25" x 6.5"
2022Rigel Quik Finder Heater 2.5 0.2 16 x 75 mm .5" x 3"






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