This Cheap Gadget Converts AA Batteries Into A D Battery - Here's How

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Despite the rise of rechargeable lithium-ion batteries, there are still many times when non-rechargeable batteries are the better option. Among the most common of these is the ubiquitous AA battery. In fact, many of us will have a collection of these stored in a kitchen drawer or tucked away in a workshop unit. This is because the battery type is used in many common household electronics, including remote controls, clocks, smoke alarms, flashlights, thermostats, and radios. It's worth noting that rechargeable AA batteries are also available. 

In short, they're convenient and usually ready to replace at a moment's notice. What's far less common in the nation's battery drawers is the AA's bigger sibling — the D battery. Despite being used in items like larger flashlights, lanterns, radios, and some emergency equipment, D cells are bought less frequently. 

And there's the problem. While most of us will have a ready supply of AA batteries at hand when the TV remote fails, the same is less likely when a D-battery-compatible device finally needs fresh power. This is where a handy, cheap, and practical device can come to the rescue. The item in question is the DSLRKIT AA-to-D battery converter, a device that, for a few dollars, can save you from the frustration of a likely fruitless hunt for the rarely seen D battery in battery drawers.

Let's take a closer look at the cheap gadget that's worthy of a place in your battery drawer. 

The device itself is, unsurprisingly, the size of a D-cell battery, with a standard set of battery contacts and contact springs. Using it is as simple as inserting up to three AA batteries into the adapter, then inserting the adapter into any compatible D battery device. 

While there's an obvious size difference between the batteries, both types are rated at about 1.5 volts ( although rechargeables are commonly only 1.2 volts). This is important because the adapter's parallel architecture can accept multiple AA batteries without increasing the voltage. For comparison, if the adapter were configured in series, then three AA cells would produce 4.5 volts (which is why some battery packs are marked as S or P).

In practice, this means that the DSLRKIT AA to D battery converter will work with a single AA battery inserted. But there is an obvious downside of using it like this — the capacity of the battery will be significantly reduced, essentially reducing how long a device can run. This is why the adapter's ability to accept three AA batteries is useful. This doesn't make the device more powerful, but it does increase the available energy, allowing it to run longer before the batteries are depleted. 

A pack of four of these gadgets costs $6.90 at the time of writing, making it a cost-effective upgrade for your drawer full of AA batteries.