Energizer L91BP-8 Ultimate Lithium AA Batteries (8-Pack)

I bought these almost a year and a half ago, for a door lock. Can't believe that they are still working this long. Mind you, they're in a outside door lock and still haven't had to replace. Highly recommend

These batteries -- actually cells -- are drop-in replacements for 'AA' cells in most devices.Nonrechargeable (called 'primary') lithium iron disulfide (Li-FeS2) cells like this have three advantages over 'regular' 1.5-volt alkaline or heavy-duty zinc-carbon dry cells:1. Much higher energy capacity. How much depends mostly on the amount of power draw from the device.2. Much longer shelf life -- cells are now marked 'best before' 15 years from date of manufacture!3. Much lighter weight -- useful when backpacking and many other applications.4. More power output in cold conditions.5. Much less likely to leak and corrode devices from the inside.The main disadvantage is cost. Additionally, a few devices don't understand the discharge curve of the lithium cells and prematurely indicate full discharge of these batteries. If you want to measure the capacity of these or any other rechargeable or nonrechargeable batteries or cells, I highly recommend the expensive but very well built The ZTS Multi-Battery Tester With Case - MBT-1.A somewhat cheaper option, if you don't need the highest possible capacity/runtime but do want the other advantages, are Energizer Advanced Lithium Batteries, AA Size, 8-Count.

These are expensive. I only use them for specific purposes where battery life and / or weight are important. In this case I'm using these Lithium Iron Di-sulfide batteries for a headlamp I'm using for backpacking. These are 33% lighter than alkaline batteries and they provide about 25% more life in my headlamp with a voltage curve that is much flatter than alkaline batteries. A flat voltage curve means voltage remains more constant from start to end of battery life. And that means my headlamp doesn't start out bright then steadily degrade to zero. With these lithium batteries, performance remains more consistent right up until they abruptly run out of juice.That translates into 10.6 hours at full power instead of 8.5 hours. Or, 116 hours at low power instead of 93 hours. That means I can carry fewer batteries and less weight. The flat voltage curve also means that Li Iron Di-sulfide batteries also handle a high drain device like a headlamp better than alkaline batteries.They also perform much better in cold weather so winter backpacking is a good use of these batteries. In sub freezing temps the battery life advantage over alkaline batteries can be as much as 4X with a drastically more consistent voltage..

I have Blink outdoor cameras, and even though there is a warning to only use lithium batteries, I really didn’t think much of it, and was using “copper tops.” Well imagine how thrilled I was when after 3 days, they were dead. LolI ordered these, as they’re the most recommended for security cameras running on batteries, and so far so good!Learn from my mistake - always ensure you’re using the recommended batteries for your devices. Not all AA/AAA and the like are actually the same just because they fit!

The Energizer Lithium AA battery 8-packs are great value. I discovered these batteries as they came with my Apple wireless keyboard and mouse. I was incredibly impressed by the longevity of those particular wireless devices, when powered by these lithium batteries. I went several months without thinking about batteries in them. By comparison, afterwards, I used traditional alkaline AAs and the same devices lasted only a few short weeks.Now I am again enjoying the benefits of these lithium batteries. This 8-pack sold on Amazon is a particularly great value. At first I thought the lithium batteries were too expensive, when I saw a 2-pack in a store, for nearly ten dollars. With this package on Amazon, the batteries usually cost around two dollars each. A great value and not much more than alkaline batteries, for a lot longer lasting power!Lithium batteries also work better in extreme temperatures. If you, for example, have an outside thermostat for a weather station, this will work in the winter, whereas an alkaline battery may not.An interesting tip, when my higher power devices, like bluetooth keyboard, runs low on power. I go ahead and pop one of the used lithium batteries into a clock. I'm not sure how long it will last, but it's a great way to recycle at least a few of your almost drained lithium batteries.Now I've started using these, new, in powered toothbrushes, and I find it's a lot more powerful and longer lasting.I highly recommended these for devices that quickly drain regular alkaline varieties.

Excellent long-lasting batteries.

These batteries last forever and handle cold weather extremely well. Be aware that performance stays high until right before they die then it is a very rapid drop. Price beat what I could find in stores