Kratax Rechargeable Lithium AA Batteries 8 Pack 1.5v 3500mWh li-ion Rechargeable Batteries with 2h Battery Charger, 1600 Cycles Long-Lasting, Constant Voltage Output for Game Controller, Electric Toy

I've now used these batteries for a year and have recharged them several dozen times. They work extremely well in my Schlage door locks, game cams and older Fenix LED flashlights. I will definitely repurchase these when needed.

I have about 20 of these now and none have failed. I use them mostly in audio devices (wireless microphones, portable recorders, and mixers, etc.) They clearly have much more power than NiMH rechargeables, and because they deliver 1.5V instead of the 1.2V you get from other rechargeables, some devices work considerably better (shavers, portable LED lights, etc.) The only real downside is that because these cells have their own internal voltage regulator for a constant 1.5V, you never know how much charge remains. If your device shows the battery level, it will always show full until the charge is completely gone. Also, note that any rechargeable AA or AAA Li-Ion cell requires a charger that dows 1.5V. You should not try to charge them on a charger meant for NiMH.

These rechargeable lithium batteries are perfect for my Blink camera system.

So I've purchased around 50 of these over the last year for my business - we use them in wireless mics, clickers, and wireless in-ear monitors. They work well and last a long time however there is something I noticed that is a potential problem - these DO NOT charge like a regular li-ion battery. I purchased some larger smart chargers to charge them and I found that they do not fully charge. I believe this is due to the charging regulator inside the batteries themselves. A typical li-ion charges at 4.2 volts - but these, if you read the fine print, need to be charged at 5 volts. So I can use the larger smart chargers to charge them initially up to roughly 97%, but to get them to 100% charge, I need to put them into the "dumb" chargers that come with the batteries as those run off USB (5 volts). Kind of a pain but still a money saver over alkalines, especially when you consider we'd go thru several hundred alkalines a year prior to moving to these...UPDATE: Just had the 1st casualty. Battery rolled off the table and dropped on the concrete floor (about 3') and the end broke open. It's completely dead. Hopefully it's just a fluke...

Didn’t need these right away as the lithium batteries I already had in my security camera were fine when I received this order. They recently needed to be replaced so I charged these rechargeable lithium batteries for a few hours until the charger indicated they were ready to go. They would not power my camera at all and of course my return window has closed. If you buy these, charge them and test them right away so you can send them back if need be.

Update 8/13/2022: the camera is not responding, so I swap in the other two and got it up again. It’s been consistently lasting 30 days. Pretty good. Definitely save some money.Update 7/13/2022: today the camera is not responding. I swap in the other two batteries aTo get it back online again. So it lasts exactly one month in a high traffic area (35-40 events a day, record the maximum one minute each time). So there you go, these rechargeable batteries last 4 weeks versus Energizer 7 weeks. These rechargeable make don’t last as long, but will save month in the long run.Original review 6/12/2022:I bought these for my Blink XT2 cameras. The Energizer ultimate lithium are too expensive and my camera happens to be in high traffic area. I will eventually pull a usb cable in the future, but for now I’m giving these rechargeable lithium batteries a try.After I receive these (4 pack), I installed two, and also put the other two in charger, so I can run a comparison. The first two runs fine, but the red low battery symbol stayed for entire day and doesn’t seem to go away. I then swap out and put the other two, freshly charged, into the camera. It took maybe 10 minutes for the low battery symbol to go away, so there you go. Make sure you charge them when you receive.No idea how long it’s going to last. For comparison, the energizer lasts about 7 weeks. I will report back on how long these rechargeable can do.

Charger seems to work more efficient than some other brands.

I have 5 Blink cameras. I have 20 batteries. I have ran these cameras through all four seasons. There has not been any issues. When I run the batteries down, especially on the high use cameras, I charge them up when I swapBefore I go to swap out again, I top them off in the chargers.The reason I do it this way is because if a high use camera has drained the battery down to complete depletion, I don’t want it sitting at the low charge state, waiting until I need it again and then the charger may not charge it due to too low of voltage level.It could go into the danger zone of too low-voltage and never recharge again. I haven’t had this issue with these batteries, but I have with my power tool batteries and vape batteries.So back to the cameras, the batteries, (AA) work well. I haven’t used them in other devices, but I am planning on using them in a smart lock.They saved me a ton of money by not having to buy disposables. When the first camera reports battery failure, I replace all the cameras batteries. I wish the cameras report an actual battery life remaining, but I would say they last at least a month and a half if not longer depending on usage.They charge very fast with no issues.