Power Sources
The DewBuster™ Controller may be operated on a 12V Battery or 13.8 VDC Power Supply (fully charged 12V batteries measure 13.8V). Commercial heaters are not designed to operate at voltages higher than 15V, so the latest DewBuster™ Controllers incorporate a 16V heater shut-off to protect your heaters from burning up if your power supply should malfunction.

As shown above, DewBuster™ Controllers with Powerpole® connectors can switch between different pigtails to fit various power sources. I highly recommend this option so that if you change power sources you will not have to send your DewBuster™ Controller in to have the power cord changed, you simply order a pigtail to fit your new power source. For more information see my FAQ on Power Cords.

If you need help selecting a battery see my FAQ on power sources. If you are considering a PowerTank, remember that it is just a "Jump-Start" battery with extra features. If you do not need the extra features, consider a conventional Jump-Start battery, they are available at tool or auto parts stores at much better prices. 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. Your power supply output should not exceed 15V because you risk damaging your heaters.
  • DC OUTPUT AMPS - A wimpy power supply's voltage will drop each time the heaters are pulsed, so choose a power supply rated for at least twice the maximum Amps you will use (see heater manufacturer's web site for Amps). Be sure you are looking at the power supply's "Continuous" DC Output Amps (not "Peak" Amps).
  • LINEAR POWER SUPPLY - "Linear" power supplies 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 a Linear Power Supply is able to supply enough Amps it WILL WORK, but it is hard to predict whether a given Switching Power Supply will work so 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.
There are many "HAM Radio" power supplies available. Try searching the internet using keywords like "13.8 Volt 10 Amp Bench Power Supply". For customers in the USA, Pyramid makes several reliable and reasonably priced power supplies including these popular models:
  • Pyramid Model PS14
  • 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 PS9
  • 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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