Top 5 AR-15 Red Dots That Take AA and AAA Batteries

Red dots have been around long enough that most people consider them a necessity for their AR-15. Shopping for one is like shopping for a pair of shoes. All different prices and sizes are available to fit your red dot needs. I have a few optics that are FDE instead of black. I’m surprised there aren’t more color options with optics since the AR-15 world has turned all shades of everything. I’m not saying I want a bright blue sparkly optic on my gun, I’m just surprised it’s not a thing.

However, color options for optics aren’t the point of this article. Instead, I want to talk about the types of batteries they take. I switched to an optic that used larger batteries because my optic went dead once in the back of an armored vehicle right before we deployed to a search warrant. As luck had it, I had an extra battery, but it was so small I dropped it. Because it was dark, I couldn’t find it again. The battery compartment was in the side of the selector switch and needed a flathead screwdriver to get off. After that, I switched to optics with larger batteries for the run time and ease of battery changes.

There is nothing wrong with optics that take different sizes of batteries. Some optics can run for years on one small watch-size battery. But when I’m using a larger optic on my AR-15, I like optics that use common batteries that are easy to change. By common, I mean AA and AAA, and maybe CR123 or CR2. Smaller dime and quarter-size batteries like the CR2016 or CR1632 are not as common, and they are harder to change. Larger batteries can be changed faster, and the optic often runs longer with heavy use.

Just about everyone has an AA or AAA battery lying around somewhere and even CR123 batteries are easy to get. Compact items are normally good, but it’s hard to keep track of a tiny battery let alone change it when you’re in the field. Here are five good red dot options if you are looking for a model that uses a common/larger battery type.

1. Sig Romeo 7 (AA battery)

I know, there are a lot of Sig Sauer optics on this list. I like other brands too and I own other brands of optics. But Sig Sauer got it right when they started making simple, durable optics with common batteries that are easy to change. That’s why this is the first one on this list and is one of my all-time favorites.

The Sig Romeo7 red dot is a full-size optic that works great on full-size to compact-size rifles. It’s powered by an AA battery that can be changed in less than 10 seconds in the field. The battery is not the only reason I like this optic. It’s one of the simplest while still having some great features. I have never been a fan of optics that have so many functions built in that you need an instruction manual.

That’s too many settings to remember for one optic. The Romeo7 has an on and off switch and that’s it. Turn the power knob to the right and the optic comes on. Turn it more and it gets brighter. If you don’t turn it off, no problem! It converts to motion activation on its own and shuts off. When you pick up the rifle, it turns back on.

I have other optics with this feature, but I can’t remember how to program them for shake-a-wake mode. I could look up the directions, but I would just forget again.  When you must hold down both buttons for five seconds and then press another button three times and so on, it’s too much.

2. Sig Romeo 7S (AAA battery)

If you couldn’t tell by the name, the Romeo7S is the same optic as the 7, but smaller. This optic works great on AR pistols but can be used on a full-size AR-15 too. The function is the same but in a smaller package. The AAA battery can be stored in the grip or stock of the rifle and changed in seconds in the field. The glass is smaller, of course, so you don’t get the same view as the larger Romeo 7, but it’s built like a tank. I have been using the 7 and 7S for a while and have never been disappointed in them.

3. Viridian GDO 20 (AAA battery)

Going down another size is the Viridian GDO 20 green dot. This one holds the battery under the optic and loads from the front. Viridian claims green is better and makes all their optics with green dots. I don’t mind either color, but green is easier for some people to see. This green dot is controlled by two buttons on top. Tap either button to activate it and then hold it down to turn it off.

4. Sig Sauer Romeo5X (AAA battery)

If you want a red dot that will work for a rifle, AR pistol, or some other PCC, the Romeo 5X is a rugged compact optic that also runs on one AAA battery. Just like the Viridian, the battery is housed underneath the optic. To change the battery, simply unscrew the cap and pull the battery out. My Romeo 5X has been beaten up and used on all sorts of guns over the years. It’s still working, and I’ve never had trouble keeping it sighted in.

My only complaint with the 5X is you must hold the power button down for three seconds before it turns on. Three seconds doesn’t sound very long, but it’s not ideal if you plan to use the optic for home defense. When your brain is going haywire because the unthinkable is happening, pushing a button and holding it for a few seconds is almost impossible.

5. Aimpoint Comp 4 (AA battery)

This one is last on my list but it’s not because of quality, it’s because of price. If you want to invest in a powerhouse brand, the Aimpoint Comp 4 can run for 80,000 hours and uses a single AA battery. The cost of a Comp 4 would buy you several of the optics above, but Aimpoint has the bragging rights of being used by the military.

No matter how many reviews and home tests people perform on an optic, you can’t compete with a battle-proven product. The Comp 4 is about the same size and shape as the Sig Romeo7, so it really comes down to the price if you like these optics. I have never had any problems with the Romeo7 red dot, but I won’t place bets on it against the Comp 4 either.

Final Thoughts

All these optics are great, durable red dots that would work on any AR-15. If you don’t really care about the battery type, then you have lots more options. Most optics have an unbelievable run time listed by the manufacturer and many can run a long, long time. But throughout my law enforcement career, I’m surprised how many times I’ve picked up a gun only to find my optic was dead. That’s why I use backup sights. But it’s also annoying if you need a battery and can’t find one without a special trip to the store. AA and AAA batteries are easy to find, and most people already have some lying around.

So, if you’re in the market for new red (or green) dots, give one of these a try!