LP Rechargeable 9V Lithium Batteries - 600mAh Long Lasting LI-ion Batteries with Micro USB Charging Station - 4-Pack 9 Volt Batteries

These are good quality batteries definitely great for the price. People need to remember batteries need to stay charged don't let them sit dead very long so over time even though you don't use them charge them time to time keep the charging cells active.

I wanted to buy 9V rechargeable batteries for a while now and these seemed to be some of the best on Amazon. Specifically, I wanted to use them mainly for some of my vintage guitar pedals (that don't have a PSU adapter) and they've been working well for as long as I've been using them.Then I figured I would try them on a smoke detector since I usually change out the regular 9V batteries every spring. I installed the rechargeable 9V battery on 2/2/25 and it died on my on 7/18/25 which means it lasted 5 months and 16 days (166 days). So almost 6 months which isn't too bad.Overall, I like them and have since bought more to have as spares.

I love these things! 9V batteries always feel like a hassle—either they drain too quickly or sit around too long and die before you use them. These rechargeable ones completely fix that issue. I use them in my smoke detector, carbon monoxide detector, and car remotes, and they work great. They charge fast, have a handy LED indicator to show charging progress, and best of all, they charge via USB—how cool is that?! No more wasting money on disposables. Highly recommend! Nice little case, actually reused for something else and kept it.

These only last 30-40% as long as a conventional battery in my TENs unit, BUT very cool and handy batteries! I love that I can recharge one in a few hours off a basic micro usb cable, instead of a specialized charger! With these, I ALWAYS have a freshly charged battery on deck when one runs out of juice. Really happy them.

Rechargeable lithium batteries, I like them

Batteries arrived yesterday and charger perfect for what I needed.

BUYER BEWARE.I wrote a 3-star review of this back in the day (May 2024), because I thought the batteries might still be useful for something. But I'm reducing my rating on this to one star. (I'd make it ZERO stars if I could figure out how to do so.)I have yet to find a single thing that will run properly on the <8.4V these "9V" batteries put out, so I'm considering this to have been a bad investment. If they work great in wireless microphones, bravo; but they're not good enough for my DVM or anything else I've tried them with.Also, please note my comments in the original review about how long it took to charge the batteries (literally, multiple days). Combine this objectionable bit of design with the batteries' inability to run anything that actually expects 9V, and they come out as a very expensive and inconvenient way to do 2S LiIon batteries.ORIGINAL REVIEWThis looks like a pretty decent package, but I'm still trying to figure out a couple of usage things, and I have one particular comment about the quality.Not all of the four batteries would charge up to the nominal 8.4V. One only reached 8.1V after several days on the charger. The other three did get to 8.4V (one slightly above, which I find curious).I'm still trying to figure out what the dancing status LEDs are supposed to mean. While all four of the batteries were charging the four LEDs alternated red/green/off, about 1 second per state. It took maybe 20-30 hours total to charge any of them up to where the LEDs did anything different; the change was that the LEDs started showing solid red (for 5 seconds and more) alternating with the red/green/off, which I presume is charger-speak for "I'm charging the cell(s) in these sockets". At this point I unplugged the charger and checked the voltage of all the batteries, discovering that some but not all had gotten up above 8.2V. I presume the "long red" indicates that a battery is getting a constant-current charge (instead of the constant-voltage that I presume is being indicated by the red/green/off), but I don't actually know this.As noted, one of the batteries would not charge above 8.1V. This is still useful so I'm not going to demand a refund or replacement but it makes me worry a little about how much life I can expect from all of them.Overall, everything seems to be as advertised, so I'm satisfied with the purchase. The charger seems fairly sturdy (the battery snaps in particular are reassuring solid). The batteries themselves seem to be well made. Only use will tell how durable they are.Some information about how to read the LEDs while charging would be extremely helpful. I did not see any such info on the item page, does it exist somewhere?UPDATING THIS REVIEW in September 2025:

It's great!