USB 9V Rechargeable Battery- 9 Volt High Capacity 650mAh Square Lithium Batteries with Type C Port Cable for Smoke Alarm Detector,Wireless Microphones & More (2-Pack)

It took some time to find the Green LED, but it is there and very, very, small. The only thing I don't like is they cannot be recharged with a standard 9V charger, but other than that it does the job.

I have several little audio items that run on a standard 9 volt batteries. I was attracted to these rechargeable batteries so I could just charge them with a USB charger and not have to keep buying 9 volt alkaline batteries all of the time. I also liked the little charging port on the batteries, but noticed there were no charge/discharge lights to indicate status. Being an electrical engineer, I measured the voltage on each battery and was happy to see something 9.03 or 9.04 volts, with no load. I assumed they were fully charged already and tried them out in my devices. Nothing. I measured voltage again with my DVM and they both read zero volts. That's odd, first read full voltage, then zero. So I charged them overnight with the a small USB charging device which monitors both output voltage to the batteries and current. Voltage was OK on the charger but the current was zero, which meant the new batteries were not taking a charge. Only when I connected the new batteries to a larger battery pack designed to be a portable charging device for traveling, did both the new batteries take a charge and work when placed in the devices. Bottom line... The batteries are shipped with no charge, but may measure a full scale voltage on a DVM. Huh? If they had battery status lights, like stated in the Amazon ad, I probably could have avoided all of the BS I did at first. I gave this review 4 stars because of the confusion I had at first. I assume these batteries will last much longer that a typical alkaline battery, but that remains to b seen as time goes on.

Price paid was similar to what I’d pay for Alkaline.Better for environment, better on my wallet, and easy to use,No need to buy special charger, comes with USB wire!Great deal, fast shipping, & NO HASSLE!Thank you seller

These batteries never worked and would never charge up. Complete waste of $

One did not hold a charge, the one that does works as expected

this doesn't have the same "oompf" of a normal alkaline battery. i'm not sure if it's the lower voltage or the peak discharge, but running a solenoid on this made it "skip"in addition, it didn't last nearly as long (~4 months) as a regular alkaline (12-18 months) and discharged completely in mild cold (~0C)update: dropped another star because, even though they claim to be "lithium" batteries, they self discharge to zero in a matter of months even just sitting on the shelf

Having a USB C charge port on the side ups the game for these rechargeable batteries. In many applications, you can leave the battery plugged in and just charge it up. That essentially makes your device a USB rechargeable one. Probably a good idea to also make a front side charger port too since many batteries are flat mounted. These tested at 9.22 volts and held a charge for a pretty long time. Easy to recharge using the supplied or any USB C cord. It has the super sensitive short circuit safety feature so if you touch the terminals with a common metal for even an instant, it goes dead and won’t reset unless you plug in the charge cord for a moment. That should be changed to reset after a very brief short circuit ends. I guess they are being pretty cautious and safety first is not so bad. These are a buy.

The first set I received 1 battery was showing fully charged however it only lasted about 4 hours in a smoke detector but when I plugged it in to recharge the blue light came on right away. So I was able to exchange them for another set which so far are working great