XTAR AAA Lithium Rechargeable Battery Triple AAA Batteries Rechargeable 1.5V 1620mWh (8pcs 1620mWh 1.5V AAA)

So far so good. I tested every one of these batteries and they all tested to their advertised mAh rating. I've been using NiMH for almost 20 years in various capacities and they always left me disappointed by the 1.2v voltage. These Li-ion replacements seem to be a great replacement. I have noticed that they get pretty warm in high current applications like my LED flashlights. The cell inside the battery package is a 3.6v li-ion. To get 1.5v the package includes a buck converter which regulates the voltage down to 1.5v. This means the voltage discharge profile is very flat. This is great since you don't experience weak batteries towards the low end of charge. Unfortunately this also means that when the battery is discharged, it drops voltage immediately and vive little to no warning.

I use these everywhere, even outside in my weather station. They hold a charge for a long time and beat leaky alkaline batteries.

There batteries seem to run out sooner than nicd batteries

These AAA batteries have been tested to easily be the highest capacity AAA batteries out there. I've tested these XTAR batteries along with the CZVV/Hixon AAA batteries which are popular on Amazon along with a Vapcell 3.6v 10440 cell and a regular alkaline Energizer Max AAA. Energizer MAX AAA: 639mAh/960mWh Initial Voltage: 1.61V (≈450mAh at 500mAh discharge tested on product sheet) CZVV/Hixon AAA: ≈720mAh/1080mWh Initial/Consistent Voltage: 1.52-1.51V (Rated: 730mAh/1100mWh) or 98% of rating Last seen capacity before hidden/undocumented 1.1V mode: ≈585mAh/880mWH? (Needs a retest) XTAR AAA: 970mAh/1455mWh Initial/Consistent Voltage: 1.53-1.54V (Rated: 1000mAh/1620mWh) or 97% of mAH rating and 90% of mWh rating Capacity before 1.1V: ≈720mAH/1080mWh Vapcell 3.6V 10440 AAA: 361mAH/1300mWh Initial Voltage: 4.17V (Rated: 320mAh) or 112% of mAH rating While the mWh rating on these batteries is fairly inaccurate, at least at the high discharge current of 500mA, These XTAR AAA batteries have at least 250mAH/375mWh more capacity than the popular CZVV AAA batteries and even 155mWh more than a trusted and reliable brand bare 3.6V cell. The CZVV batteries were found to also have a low 1.1v mode, though I didn't get to see the exact mAh figure this occurred at as this feature is not listed by CZVV. These XTAR batteries also have far more capacity than the Energizer alkaline at high discharge and higher capacity than NiMH batteries such as the Eneloop or even the Eneloop Pro batteries which have rated capacities of 980mAh/1176mWh while the XTAR provides a consistent 1.5V for most of its life. The XTAR batteries also recharge 4x faster or more than a NiMH battery would take to recharge. These batteries are best used in devices that would benefit from the higher voltage and have higher power demands such as Quest 3 touch controllers compared to a TV remote and would benefit from higher capacity for fewer battery changes as well as more reliable controller tracking along with displaying an actual full charge. While it is still too early to test reliability, I will keep this review updated with any new findings including reliability updates. Based on reviews of other lithium rechargeable batteries, these could have higher self-discharge rate than something like a NiMH battery.

I was initially impressed with these batteries. I did an initial capacity test and was pleasantly surprised that the ones I received measured 1420 mWh. Less than specified, but the highest I've measured hands down. I also tested them for "low power, always on" behavior and was impressed at their longevity. Add to that they are not oversized, I thought they were fantastic. Then I started putting them in real devices and that's where the disappointment came. In more than half of my devices, they simply don't work and it quickly became obvious as to why. The bottom of the battery is where the negative terminal makes a mechanical connection, and the button top is where the positive terminal makes the positive connection. Many AAA powered devices employ a coiled wire spring to force the mechanical electrical connection to one or both of these points, often the positive connection. Many AAA powered devices employ a flat plate for the electrical connection at the bottom of the battery. These batteries create a major problem at both of these points because of the following. The plastic wrapping material overlaps the base of the battery at the negative battery terminal, and a flat metal plate will touch the plastic, not the metal, and thus not make a reliable connection or any connection at all. If a coiled spring is used for contact to the positive button terminal, most coils are much larger than the button top on these batteries and simply make contact with the region between the button and the edge of the battery which is an insulator in the case of these batteries. You can see these issues in the pictures provided. I checked all my name brand consumer AAA batteries and none of them have either of these issues. They have metal at the region between the button and the edge of the battery, and a wider button to begin with. So the spring coil will always make good metal to metal contact. And, none of them have the negative base encumbered by overlapping plastic. There are devices that have flat spring tabs or plates that will work with the button tops, and springs at the negative terminals which will work with these batteries. But for me that's the minority of my devices. I used some folded tin foil inserted on both ends to make the connections work to prove my observations and it was successful, but that is not recommended for actual use as it can short out the battery, and if the battery protection circuit does not blow open when shorted, the lithium may burst into flames that cannot be extinguished. I then used a voltage meter to check the top corner of the battery (with the plastic peeled back at the very top) with the top button positive terminal of the battery. Sure enough, a solid 1.5 volts. This means, if a deformed coiled-wire spring was to bend sideways during battery insertion, and pierce the plastic coating near the corner, and make contact the the button, it will short the battery out. If you then put the device in your drawer, or your suitcase on an airplane, it could become quite a dangerous situation.

Nice for those apps which dont like the low voltage of nimh. Did not work in my weather radio because the batteries regulator seemed to create enough electrical noise preventing reception without messing with the antenna. Great results in remotes and other uses which might have been nimh.

Works great for my voltage sensitive Dymo Rhino labels maker that doesn't work with the typical 1.3v AA rechargeable batteries. Saves me from buying a proprietary battery pack for the darn thing.