Review on Long-Lasting EBL 9V Lithium Rechargeable Batteries With USB 5400MWh Capacity (Pack Of 2) by James Martin

I decided to test the performance of this battery by first depleting it completely, then recharging it while measuring the voltage at scheduled intervals. (See attached photo). Note that my multimeter gives the depleted voltage in millivolts so it’s actually reading 0.0002V. But after just five minutes on the charger, it already came back to 6.97V. From there the voltage inched it’s way back up, but it really didn’t change substantially. It’s not perfectly constant, but this battery gives a very nice, steady performance over its life and it dies abruptly once it’s been depleted.I also wanted to test the longevity of this battery compared to some popular alternatives. I tested this against a Duracell 9V alkaline battery and Energizer’s Ultimate Lithium 9V battery by putting all 3 in a 9V flashlight to see how each one performs under a constant drain.- Duracell Alkaline: Given the way an alkaline battery gradually diminishes, and my flashlight becomes gradually dimmer as it dies, it wasn’t easy to discern a reasonable cutoff voltage where I called it dead. So I decided to measure how long it takes to drain down to 7V, because that’s about where most of my 9V devices fizzle out anyway. In my flashlight, this took approximately 12 1/2 hours.- Energizer Ultimate Lithium: This one also held a fairly steady voltage. Even now it shows over 7V on no load, but it can’t draw any meaningful current anymore. I got about 18 1/2 hours of use out of it. Not bad, but disappointing considering the high price.- EBL 9V Lithium: By far this was the most straightforward to measure. It brightly lit my flashlight, and died abruptly at 13 1/2 hours.So this ran about 8% longer than the Duracell did. Energizer Ultimate Lithium ran about 37% longer, but it’s expensive and non-rechargeable. As of this writing, this product is listed at $6.25 per battery. The Duracell and Energizer are listed here on Ebay at $3.50 and $7.19, respectively. At these prices/ lifespans this rechargeable battery pays for itself in about 1.65 charge cycles compared to the Duracell, and 1.2 charge cycles compared to the Energizer.I recognize that this has been less of a traditional review, and more of a data presentation, so I thought I should add here that I’m very happy with these. They performed very well over a charge cycle, and the lifespan exceeded the alkalines that I used. Plus it costs next to nothing to recharge them, so it’s a great money saver. The USB recharge is fast and convenient. This is very innovative, and I’m rapidly phasing out my old disposable batteries.Edit: 11/10/2022I bought these a little over 2 years ago and they’re still going strong. As I noted in my original review, these have a little over 8V on a full charge, then they discharge to about 7 volts before they die. This is fine for all of my applications (mostly tools) but if you have a more sensitive device, I would recommend Energizer’s NIMH rechargeable battery. The downside is that they have less energy density and you have to buy a special charger for them, losing the convenience of this USB charging system. (The Energizer and EBL chargers have both worked well for me). But if you do need something that’s a little higher voltage, the NIMH maintains 8.4V all the way to the very end of its charge cycle.