Do You Have a “Phantom Drain” in Your Electrical Circuit?
We revamped a defunct off-grid solar system for a client, tested the equipment post-implementation, and found that the electrical circuit drew 1,300W while “everything is off.”
We call such a large, mystery load drawn by a circuit when the user/owner claims "nothing is running” a vampire/phantom/ghost drain. They’re more common than many may think — we encountered two within a couple of months. One was even a fire hazard because it overloaded the house’s wiring.
So, what did the 1,300W “phantom drain” mean for that client?
Their solar field produced a peak power of ~800W in the winter months. The 1,300W drain would put the system in a constant deficit if it was consistent and 24/7. The client could not rely on solar alone to meet all the energy needs without adding production and storage capacities (i.e, panels and battery).
The 7.68 kWh battery we installed can comfortably run everything in a typical household overnight (except heater, water heater, and A/C). However, it would last about 4 hours after dark with a consistent 1,300W draw.
A 1,300W power draw is equivalent to ~20 modern fridges running simultaneously. If the load were consistent and round-the-clock, it’d cost ~$18 per day (~$540 per month) at $0.50 per kWh. Ouch.
These vampire drains run into money no matter how you get your power. (If you get eye-watering SCE bills even if you don’t run power-hungry appliances, they could be the issue!)
If your off-grid system has decent capacity but falls short even if the equipment works properly, such a “leak” could be the culprit. You'd be better off addressing the issue before spending money to add solar panels or battery capacities.
So, what are some potential causes of these “phantom drains?”
An inefficient or malfunctioning power supply draws too much electricity.
An electric heater is left on while no one is using the room.
A few old, energy-inefficient fridges humming in the basement.
Most of the “leaks” are obvious when you look closely, while others require some sleuthing to uncover. These consistent power draws mean you’d need more solar panels and battery capacity to keep your system running if you don’t address the root cause.
Meanwhile, appliances with a high peak power require an inverter with high surge capacity, increasing the cost of a solution. These may include an overly powerful water heater (especially if it’s wired into a circuit running everything else in the house) or our pet peeve, well pumps that draw a huge amount of power to start.
Installing a new well pump isn’t practical, but knowing the surge power of your current one will allow you to dimension your system to meet your needs. For example, you can avoid the hassle and expenses of buying an inverter only to learn that it can’t start the pump and have to buy a more powerful one.
If the water heater/boiler is the culprit, you could replace the heating element with a less aggressive one and put the heater on a timer. It may take 90 minutes to heat the water instead of 15 minutes, but it could save you hundreds or thousands on solar production, inverter, and battery capacities.
When we work with clients who are on SCE and want to adapt the “grid as backup” concept, we measure their power consumption to gain data insights before dimensioning their solutions to minimize unpleasant surprises.
You could make these “phantom drains” a non-issue by spending $30-50k on grossly over-dimensioned systems. But we don’t think that’s a good use of our clients’ money, so we do things differently. Instead of asking for tens of thousands of dollars and never seeing our clients again, we invite our clients to embark on a journey toward true energy independence with us through an iterative process.
