I’ve been a little late with Christmas decorations this year, and part of that is because I’ve been waiting for something to arrive in the mail. Rather than spending a fortune on AA batteries to power my favorite Christmas lights, I’m switching to a battery eliminator this year.
One way or another, the existence of such a device seemed until recently to be a well-kept secret.
What is a battery eliminator?
As the name suggests, a battery eliminator is a device that eliminates the need for disposable batteries. To do this, it provides a constant voltage, equivalent to that of the cells it replaces. Battery eliminators look like wired batteries and come with dummy cells that can be plugged into a wall outlet.
They come in a variety of forms, for all kinds of battery types, including AA, AAA, and even 9V. In my case, I’m looking to replace three AA batteries, which provide 1.5V per cell for a total charge of 4.5V. While some battery eliminators come with AC to DC adapters that plug directly into the wall, the one I’m using terminates in a simple USB-A plug.
Since I have a stack of old USB adapters delivering at least 5V on 1A that I found in my box full of excess cables, I saved money by going with just a USB version. I ended up buying two for about $12 each with free shipping, and a quick look on Amazon leads me to believe that’s the going rate.
In my case, I have two sets of battery powered Christmas lights that have very thin copper wiring between the LEDs. I use them to light the Christmas tree every year, as our choice of tree is far from the norm, since classic northern hemisphere Christmas trees aren’t really a thing here in Australia. This year we chose to dress up a palm tree lady who usually lives in the corner of the room (don’t knock her until you’ve tried her).
We have already used olive trees, money trees, golden palms and other small houseplants. Big Christmas lights just don’t look right, which is why I’m stuck with these battery powered LEDs.
Disposable batteries are a costly problem
Despite my searches, I can never find USB versions of these lights that quite match the ones I already have. I considered cutting off the battery case and replacing it with my own soldered USB solution, but I need to practice soldering before taking on that kind of project. I would just end up with broken lights that will need to be repaired for the next 12 months.
Like other How-To Geek writers, I’m done with disposable batteries. They make sense for some items, like emergency flashlights or item trackers, but for lights that stay plugged into my Christmas tree for a month, I’m burning through money unnecessarily. Being AA batteries, their degradable nature also impacts how I use them.
You shouldn’t have to think, “It’s not dark yet, I guess I’ll leave the tree lights off” at Christmas. Due to the way these types of batteries wear out, the overall effect is diminished. The lights seem noticeably duller after a few days of use, but in a subtle, insidious way that only becomes fully visible when you cough up three more AA batteries.
It’s like running your Christmas tree on some sort of coin-operated meter. Now, for the price of a pack of 12 decent AA batteries, I’m giving myself an early gift for next year (and all years to come).
Other Uses of a Battery Eliminator
You might think I’m a little slow, but I’ve never seen a battery eliminator on the shelves of a hardware store or supermarket. I had to order mine from an Amazon-like retailer that stocks everything under the sun, with orders fulfilled by a rainbow of third-party suppliers.
Now that I’ve upgraded my lights, I’ll probably leave the eliminators in place until next year. But it got me thinking about other devices I might want to do the same for. Although I have replaced the majority of battery-powered devices in my home, there are a few that stand out.
My partner’s original Game Boy is still in perfect working order, and nothing beats the original hardware when it comes to nostalgic gaming. I also have a MiniDisc player that still works great in 2025, with a stack of MinDiscs to go through, and since the eliminators are USB powered, I can even use this in the car.
Portable fans that you keep on your desk, kitchen scales, and other battery-powered devices that don’t rely on portability are all great candidates.
