Summary
We hear that it saves energy to unplug devices, but it’s easy to blow off this advice. Such usage is invisible and out of mind. Turns out, that energy wastage is actually quite easy to confirm.
Staying Plugged Into a Power Bank Will Drain It
I recently placed power banks in several rooms throughout my house. Much of our furniture is far from a power outlet, and this makes that a non-issue. A byproduct of this change is that I now pay careful attention to when it’s time to unplug my phone.
I like smaller power banks, and most of mine are 10,000mAh. This is enough to fully charge myGalaxy Z Fold 6twice. Yet if I plug my phone into a battery overnight, by morning that battery will be dead.
Your phone will continue to charge to make sure it stays at 100%. Even if you have a degree of battery protection limiting your charge to less than 100%, it will still continue to top up throughout the night. By morning, the external battery is likely to be dead. Instead of getting two charges out of the battery, I’ve gotten one, yet the battery has still expended its full capacity of energy.
Thing is, phones absorb more wattage per hour when charging than they expend. My phone charges at over 20W, but it does not drain by that much when unplugged. If I had unplugged my phone on time, it would not have drained its own internal battery, which is a significantly smaller one at 4,400mAh. In fact, it likely would have gone down only a few percentage points overnight. This means it isn’t even using all that energy it’s pulling from the battery. That power is literally just going to waste.
Some Power Banks and Charging Hubs Show How Much Power You’re Using
Waking up to a dead power bank doesn’t tell you exactly how much energy you’re using—unless, that is, your power bank actually displays energy usage.
Bigger banks with higher levels of energy output, such as over 60 or 100 watts, often come with displays that show how much energy is being sent out at any given time.
If you invest in certain USB-C charging hubs, they will give you this same information. When the screen shows an output of 20W, that means the phone is currently drawing 20W per hour that it’s charging.
This energy usage isn’t necessarily constant. Phones may have charging curves where they pull a lot of power when low but draw very little when close to full. Yet even if a phone goes from pulling 20W to only 3W, that’s still comparable to leaving a light bulb on that you aren’t using.
You Can Also See Energy Usage on Portable Power Stations
I live in a rural area where we lose access to water whenever the power goes out, since we have an electric well pump. Due to that, webacked up our home with tons of portable power stations, including massive ones like the Anker Solix F3800 Plus.
Each of these power stations shows how much power they’re putting out at any given time.
Quite frankly, the large AC inverter inside the F3800 uses more power than a phone does, meaning that particular battery will put more of a strain on its own battery than a phone might. But if you plug something larger, like a laptop, into a smaller battery like theAnker Solix C300, leaving that laptop charged will drain the C300 relatively quickly, even if the laptop is fully charged.
Anker advertises the C300 being able to charge a laptop four times when using a USB-C port. I watched my wife’s laptop drain the battery in a few hours from being left plugged in (to an AC outlet, not a USB-C port) while they worked. Like a phone, the laptop likely would not have drained its own battery in that time, but it happily absorbed that extra juice from an exterior one.
You Can Buy a Smart Outlet
I reviewed aTapo P210M smart outlet, and one of the reasons you might replace a generic wall outlet is to monitor energy usage. If you leave a phone charger plugged in to a smart outlet over the course of a day, week, month, or year, it will tell you exactly how much energy you’ve wasted as a result.
The number won’t appear on the outlet itself. To get that data from my smart outlet, I need to open theTapoapp. There I can get the information without doing the math myself.
To reduce energy usage, I can place the outlet on a schedule so that it automatically stops supplying power a few hours after I fall asleep. That way I can wake up to a charged phone without having to do away with the habit of charging overnight.
The same functionality is available from somesmart plugsor smart surge protectors, which don’t require you to do any electrical work in your home.
I can’t tell you exactly how much power you’re wasting by leaving your devices plugged in. That depends on how many devices you have charging indefinitely throughout your home.
Yet you can do the math once you confirm how much power each charger is drawing at any given time and then multiplying that number by the number of hours. Once you’ve hit 1000 watts, you get a kilowatt. Power companies here in the US tend to charge by the kilowatt, such as 12 cents per kilowatt. In all likelihood, it isn’t costing you more than a buck or two power month, but energy wasted is energy lost all the same.
