Whether you've got a chain or a belt drive, a basic 1/2-horsepower model or a beefier 3/4-HP machine, your garage door opener likely has a handy, pocket-sized wireless remote. These little buggers range just as widely as the openers themselves, so battery-changing practices vary just a bit depending on whether you're working with a Craftsman, LiftMaster or Genie device, for instance. It's always best to refer to your owner's manual for specific instructions where available, but if you can't get your hands on a manual, rest easy knowing these varied gizmos do share some commonalities.
Most often, wireless garage door opener remotes draw power from a tiny coin-cell battery, sometimes called a button-cell battery. By and large, these remotes take a 3-volt 2032 lithium coin-cell battery, although some require a different 3-volt coin-cell, such as a 2016 or 2450, especially if they have extra functions such as flashing LED lights. If your remote doesn't take a coin-cell, chances are it needs an alkaline battery such as a common AA or AAA.
Wall-mounted wireless keypads, on the other hand, most often use 9-volt batteries. In rare cases, wireless openers require compact A23 alkaline batteries, a special type of battery available at most hardware stores.
How to access your remote's battery compartment varies per model, but it's almost always a straightforward process. If the battery cover has a small slot, insert the flat end of the remote's visor clip, the edge of a coin or the blade of a flat-head screwdriver to gently pry off the cover. Alternatively, some covers simply slide off, and one type of remote requires you to loosen a screw or two before accessing the battery compartment.
Once you access the battery compartment, pop out the old battery or batteries and properly dispose of them. While it's legal in many states to toss out batteries in the regular trash, recycling is a more eco-friendly option, and some states legally require it.
In most cases, the remote's battery compartment indicates the direction in which you should insert the battery, based on positive and negative polarity. Coin-cell batteries have a positive and negative side -- more often than not, the positive side should face up. Both coin-cell and alkaline batteries feature clearly labeled "+" and "-" sides to make proper placement easy. When working with 9-volt batteries, ensure the contacts on the battery securely snap into the corresponding connectors. The connectors are shaped differently so they only fit one way.