Optics Planet Streamlight Sale!!! Upto 50% Off

What Is An IMR Battery? Power & Safety With Chemistry

With all of the different battery options on the market today, things get somewhat confusing. Many of the top rechargeable flashlights available can use something called an IMR battery, but for those who are not a flashlight or battery enthusiasts, that doesn’t mean much. So what exactly is an IMR battery?

The first thing to understand about IMR batteries is that the letters ‘IMR’ an acronym. With that in mind, it again brings up the question ‘What is an IMR battery?”

What is an IMR Battery?

An IMR battery is a rechargeable lithium-Ion Manganese battery that is Round. The first letter represents the anode, the second the cathode, and the third the shape. 

These batteries differ from other li-ion rechargeable batteries in their chemical makeup. An IMR battery uses Manganese Oxide, where other types of Li-ion rechargeable uses Cobalt Oxide in their cells.

What Kind of Capacity does an IMR Battery Offer

One thing that draws flashlight enthusiast to specific batteries is their mAh figures. The higher these numbers are, the more charge they hold. With this in mind, many people second guess IMR batteries are because the mAh numbers are half the size of other Li-ion rechargeable batteries. 

The reason these numbers are lower is because of the Manganese instead of the Cobalt. Manganese isn’t able to reach the same capacity as Cobalt, but IMR batteries are equally reliable and have a higher drain with lower temperatures. Even with crazy bright lights.

Different Shapes and Sizes of IMR Batteries

As like most other batteries, IMR ones come in a variety of shapes and sizes. IMR batteries are currently available in all of the most used sizes of other Li-ion cells, including 18650, 14500, and 16340. These could be used in many of our top 18650 light choices.

Are IMRs a Safer Choice?

Many people question how safe IMRs are to use as they do not typically feature a protection circuit, although a select few companies who make IMR batteries do use it.

The internal resistance in an IMR battery stays lower than Colbalt batteries over a longer period. The internal resistance staying as low as it does is what deems IMRs safer than a cobalt cell. Because of this the temperatures also stay lower.

IMRs also offer a higher discharge rate and recharge faster than other Li-ion batteries choices. These benefits make the IMR batteries a great option for flashlights that use a higher current while operating.

Are Unprotected Batteries a Risk?

Many flashlight enthusiasts/experts strongly discourage people from using unprotected cells inside their lights. The reason for this is the charging and discharging of the battery at high rates creates internal resistance and high temperatures.

If you are not careful and neglect to monitor your IMR battery inside your light, it can create a risk for the battery.

When using an unprotected cell inside your favorite light, always monitor it closely. Never let the battery drain below 3 volts.

IMR batteries that are unprotected will not shut off on their own, so the battery runs the risk of draining too far and entering what is referred to as the danger zone.  If a cell is continually entering the danger zone, there is a high risk of damaging it, which includes no longer charging and worse.

Also, a “true” IMR can not be overcharged. But to improve long term stability of the IMR battery manufacturers put in a little nickel which then makes it so they can be overcharged. So, never allow the battery to charge above 4.2 volts, or you again run the risk of damaging the battery.

Most smart chargers automatically shut off charging once the battery reaches 4.2 volts, but accidents and failures occur with chargers just like batteries.

Purchasing Tips for IMR Batteries and Chargers

No matter if you are purchasing IMR batteries or a smart charger, always be aware of who you are buying them from. Even trusted sources sell inferior products, so don’t just rely on using a well-known and trusted website.

Before purchasing anything from any website or retailer, do your research ahead of time. You can check our rechargeable batteries buyers guide as a start.

Watch out for low priced batteries and smarter charges.

These lower prices often come at a cost to you, as you sacrifice quality for a low price.

The downfall of many lower-priced smart chargers is their algorithms aren’t as trustworthy as the more expensive brands. The algorithms are responsible for stopping the charging process at just the right time not to overcharge the battery.

Not to mention, these lower-priced options tend to fail more often than not, after only a few uses.


IMR batteries differ from other Li-ion cells in their chemical makeup. An IMR battery utilizes Manganese rather than Cobalt in its chemical composition. Lithium manganese allows for a safer battery as there is a lower risk of overheating if the protection circuit fails.

These batteries recharge faster and offer a faster discharge rate. Although they have a lower capacity compared to other Li-ion cells, they provide higher amounts of power when used in a flashlight.

Hope that you found everything that you needed on the site. Take a look around if you are looking for a new light, more info on batteries, or flashlight info.