EBL USB Rechargeable 9V Lithium Batteries - 5400mWh Long Lasting LI-ion Batteries with Micro Charging Cable - Quick Charge in 2 Hours (4 Pack)

fantastic product, they feel a bit cheap but they last very long and charge quickly. they have saved my a ton of money and are literally just the same as normal 12v batteries but rechargeable

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 Amazon 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.

I have not used them yet, but love they recharge easy, and looks like they will be wonderful.

I travel with a Traveler EC-1 guitar, and a Fender Mini Tonemaster amplifier. The amplifier takes a single 9V battery, which these seem to have no trouble powering for several hours of hotel room practice. The guitar, however, has an ESP humbucker pickup which requires a 9V battery. When the non-rechargeable battery depleted, I switched to one of these rechargeable, only to get a high pitched tone out of the guitar. (It sounds like a square wave).I surmise this has a voltage regulating circuit making the noise. I'll try adding a capacitor parallel to the battery and see if that solves the issue. Meanwhile, I will use non rechargeable batteries in my "hatchet"

Best 9v battery I've ever used! Consistent power delivery for hours. Full power for a very long time, then it quits. No problem they use a USB cable to charge them. Short recharge period. Highly reccomend- especially if you use TENS equipment.

Great price and I really like that they are rechargeable

When I got them I had a charger that would charge one at a time and somehow I missed they had a USB connection, but was happy as I have a USBc cable with 4 USBc ends and plugged them in and made for a fast charge at least for the first time. I use a volt/ohm/amp meter all the time and stuck one in there and has been working with me day and night. Put one in a toy and it got good use before my great grandson wore that toy down and we slipped in a new one and off he was gone again.I do believe they are good and will save me money down the road. I am hoping for years to come.I do hope this helps you find what you need.

Due to the charging circuit and power regulator in these batteries, they send a square wave voltage, which is clearly audible if you use these with anything that has a speaker on it, or is connected to a speaker.I thought these would be a good battery for my bass guitar, which has active pickups. No, it makes an awful whining, buzzing sound. So, I tried it in my acoustic bass guitar, with a piezo pickup inside it. Nope, same high pitch buzz. None of my instruments, that require 9V, work properly when using these batteries. They just cause signal noise that a noise suppressor can't cancel out.I tried them in foot pedal effects for guitar and bass... Same problem.I tried them in powered speakers that take a 9V. Same problem.They even interfere with the remote controller for my RC cars and boats, when using them in the handset.I can't recommend these for anything, really.The best I can say is that they caused interference or noise in the signal, with every 9V device I own personally, whereas a regulat Alkaline battery doesn't.Oh yeah, the one I was testing completely ran out of power after a couple of days of testing it for a few minutes in each device I tried it in. Maybe an hour and a half of use total.The regular Duracell Alkaline 9V I was comparing it to, wasn't new, it was one that I've had in my guitar for 3 months, got the same amount of use during my A-B testing, and it still tests at 60% full.These EBL 9V batteries are a hard pass for me. I'll be returning them.