O! Ye Gods of Watts, Oomps, and Amps!
- Last Updated: 25 August 2015
An Article Written By Kevin Gilchrist
Has this ever happened to you? Did you set up your GoTo telescope and the motors don't seem to be as loud and fast as they usually are? Was star alignment fraught with errors? Did your scope suddenly seem to think it was in South Africa? Check your power supply! If you are like most of us gear-heads you will have a collection, large or small, of Wall Warts. Those pesky little black plastic boxes with wires seem to have a life of their own.
They disappear one day, then come back a week later and they have multiplied. These purveyors of low-voltage direct-current (abbreviated DC) are a fact of life. Another fact is that they come in a variety of voltage outputs and (very important) two kinds of polarity and also a "power rating" called Amps. Usually the larger the plastic box the more Amps the Wall Wart can delivery to your device. Be sure to label your Wall Warts as to which device it is meant to power. A Wall Wart of 0.25 amps will not under any circumstances be able to power a device requiring 1 or 2 amps when it is needed. So your GoTo's hand controller may light up and let you start your alignment routine, it probably won't be able to power both axis's motors at the same time. The other caveat is polarity. Your mount or other device should have a little picture showing you if it needs the Positive voltage on the center pin or Negative voltage on the center pin. Most modern devices use Positive-on-center-pin but there are exceptions!
The second problem that our Lockwood Valley site is prone to, but also beyond our control, is the fluctuating AC line voltage. In a city or suburb that is large enough, the voltage at the outlets is relatively steady - usually between 110 and 125 volts. Out in Lockwood Valley, line voltage can vary as much as 100 volts on the low side, to a high of 140 volts! These spikes, surges and sags are just the way it is out in the sticks. Our little Wall Warts are rarely designed and built to deal with these fluctuations and we must turn to big, heavy battery packs or voltage regulators designed to keep our required voltages where we need them. Not only do our GoTo mounts need clean, regulated power, but also our computers and private networks. I said "clean" power. Another problem with our little Wall Warts is that they don't always supply nothing but DC. Sometimes a little AC can leak through an aging Wall Wart, or even a new one! They are not the most trustworthy of things we rely on and can damage your expensive equipment. If you are an imager, or seriously thinking of getting into using computers with your scope, then a voltage regulator is a must if you are setting up anywhere, not just Lockwood Valley.
We want your experiences at Lockwood Valley to be happy and productive. Being frustrated at a misbehaving scope or computer is a waste of valuable time. Be prepared: Have the correct Wall Wart or other reliable power supply and an extra, brightly-colored and long extension cord.