EBL 9V Rechargeable Lithium-ion Batteries 600mAh (4-Pack) - Long Lasting Power for Smoke Detectors, Guitar Pedals & Wireless Microphones

These days 9V batteries come in several different varieties - Zinc-carbon, Alkaline, Lithium, Ni-Cd, Ni-MH, Li-ion. The last 3 types are rechargeable and the first 3 - are not. A typical alkaline battery has more than 9V when fresh. A Li-ion cell has a nominal voltage of about 4V. A typical 9V Li-ion battery contains 2 cells, connected in series, so its nominal voltage is 8V. When fully charged such battery may develop up to 8.4V. Upon discharge the Li-ion battery voltage becomes smaller and may go as low as 6V. This is the limit, which should never be breached. According to the description the EBL 9V battery has many types of protection inside it, but I have never seen any of them in action.I bought 4 batteries several years ago and used them in scales, electric meters and smoke alarm. So far I have no complaints. These batteries last about as long as alkalines, but they are rechargeable. They are more expensive than alkalines to buy, but not that much more. In a long run they definitely save money. A typical alkaline battery capacity is 550 mAh. Compare it to the 600 mAh of this Li-ion battery.EBL batteries are made in China and you cannot trust any of the Chinese products. So I felt a reality check is in order. I fully charged one battery to 8.348V and discharged it with my trusty DL-24 load tester. Not sure what EBL does for their testing, I selected a 10 hr discharge cycle. It means the discharge current is 600 mAh/10 hr = 60 mA. The tester maintained this constant current throughout the testing. The discharge stops at 6V (3V per cell). At the end the tester showed the 473 mAh capacity. It is lower than claimed 600 mAh, but EBL states that new battery can achieve the best performance only after 3-5 charge-discharge cycles. It may be true and I did not check that.In my experience these Li-ion batteries work just fine. You just have to keep in mind that you will see 7-8V on these batteries most of the time. They will never develop 9V like alkalines. Some of the devices may not work with such low battery voltage, but so far I did not find any such devices. My scales, meters and smoke alarms do not have issues with the low voltage. If you have any concern, the only sure way to resolve it is to try.