A phantom load isn’t something that lurks in your basement with a half-mask, but it’s close kin. Many modern appliances remain partially on when they appear to he turned off. That’s a phantom load. Any appliance that can be powered up with a button on a remote control must remain partially on and listening to receive the “on” signal. Most TVs and audio gear these days are phantom loads. Anything with a clock - VCRs, coffee makers, microwave ovens, or bedside radio-clocks - uses a small amount of power all the time.
Vampires suck the juice out of your system. Vampires are the heavy black power cube that plugs into an AC socket, and delivers lower voltage power to your answering machine, electric toothbrush power tool charging stand, or any of the other huge variety of appliances that uses a power cube on the AC socket. These villainous wastrels usually run a horrible 60% to 80% inefficiency (which means that for every dime’s worth of electricity consumed, they throw away six or eight cents worth.) Most of these nasties always draw power, even if there’s no battery/toothbrush/razor/cordless phone present and charging. It would cost their manufacturers less than 25 cents per unit to build a power saving standby mode into the power cube, but since you, the consumer, are paying for the inefficiency, what do they care? The appliance might be turned off, but the vampire keeps sucking a few watts. Ever noticed that power cubes are usually warm? That’s wasted power being converted to heat. By the way, cute and appropriate as it is, we can’t take credit for the vampire name. That’s official electric industry terminology.
So what’s the big deal? It’s only a few watts isn’t it? The problem isn’t the power consumed by vampires and phantom loads, it’s what is required to deliver those few watts 24 hours per day. When there’s no demand for AC power, a full-size inverter will drop into a stand-by mode. Stand-by keeps checking to see if anything is asking for power, but it takes only a tiny amount of energy usually under 2 watts, if the phantom or vampire load is enough to awaken the inverter from stand-by it consumes its own load plus the inverters overhead, which is 6 to 20 watts. The inverter overhead is the real problem. An extra 10 to 25 watts might sound like grasping at straws, but over 24 hours every day this much power lost to inefficiency can easily add a couple $450 modules to the size of the PV array and maybe another battery or two to the system requirements. You want to make sure your inverter can drop into stand-by mode whenever there’s no real demand for AC power.
