Power Sources
The DewBuster™ Controller may be operated on a 12V Battery or a 13.8 VDC Power Supply (fully charged 12V batteries measure 13.8V). As shown above, DewBuster™ Controllers with Powerpole® connectors can switch between different pigtails to fit various power sources. For more information see my FAQ on Power Cords.

If you need help selecting a battery see my FAQ on power sources. When 120 VAC is available you can power the DewBuster™ Controller while the battery is on the charger, thereby using the battery as an Uninterruptable Power Source (use a normal charge rate, do not "Fast Charge") and if the AC power is momentarily lost you will not even notice.

When purchasing a power supply consider the following:
  • 13.8VDC OUTPUT VOLTAGE - Your heaters produce 32% more heat at 13.8V than at 12.0V which may be important when trying to burn off any dew that has already formed. You do not want to exceed about 15V because you risk damaging your heaters.
  • DC OUTPUT AMPS - You do not want a wimpy power supply, it should be rated for about twice the maximum current (Amps) you will use (see heater manufacturer's web site for Amps). Be sure you are looking at the power supply's "Continuous" (not "Peak") DC Output (not AC Input) Amps.
  • LINEAR POWER SUPPLY - "Linear" power supplies will work because they have big transformers and heavy duty regulators that can easily handle the large current swings caused by dew controllers pulsing their heaters. "Switching" power supplies are smaller, lighter, and lower priced but they sometimes have trouble smoothly regulating the voltage when the current suddenly changes. They also vary the switching cycle as current changes which can create RF noise that can interfere with your camera images. So if you are considering a switching power supply make sure you can return it if it does not work out.
  • PROTECTION FROM MOISTURE - Most Linear Power Supplies have ventilated "indoor" enclosures so you must put them in a protective enclosure to protect them from dew. I suggest a plastic storage box about twice the size of the power supply to allow air circulation inside. Hefty® makes an 18qt Plastic Storage Container that works well (set power supply on raised lid keeping it off ground then use bottom as a cover for power supply). It's OK for the power supply to get warm (helps keep it dry) but you do not want it to get hot so leave a gap under the cover for warm air to escape.
  • Ground Fault Interrupter (GFI) - All power supplies should be powered through a GFI to prevent electrical shock. Many homes have their external AC power outlets feeding off a GFI from a bathroom or kitchen (press the TEST button and if the outlet loses power then it is protected by that GFI). If you need one, home supply stores carry GFI's that may be plugged into an outlet and your extension cord then plugs into the GFI.
USA customers: Pyramid makes several reliable and reasonably priced power supplies (see below). If you find other reliable and reasonably priced units please send me a link.

International customers: there are many "HAM Radio" power supplies available. Try searching the internet using keywords like "Australia 13.8 Volt 10 Amp Bench Power Supply". If you find a reliable and reasonably priced unit please send me a link.

  • Pyramid Model PS21
  • Amazon link
  • Linear Power Supply, 13.8VDC, 20 Amp continuous current
  • Banana Jack connections (No Cigarette Socket).
  • This is overkill for smaller telescopes but a good choice for 14" and larger SCT's.
  • Pyramid Model PS14
  • Amazon link
  • Linear Power Supply, 13.8VDC, 12 Amp continuous current
  • Banana Jack connections (No Cigarette Socket).
  • Good choice for all telescopes and can handle a 14" SCT.
  • Pyramid Model PS15
  • Amazon link
  • Linear Power Supply, 13.8VDC, 10 Amp continuous current
  • Cigarette Socket and Banana Jacks.
  • If you need a cigarette socket go with this, otherwise the PS14 is a better bargain.
  • Pyramid Model PS9
  • Amazon link
  • Linear Power Supply, 13.8VDC, 5 Amp continuous current
  • Cigarette Socket and Banana Jacks.
  • Recommended only if space is tight and for no larger than 5" refractors or 8" SCT's.

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