BESTON USB Rechargeable 9V Batteries, 650mAh / 5460mWh Lithium Ion Rechargable 9 Volt Battery, 4 Pack

I have a Hyper Tough flashlight by Walmart, it is an LED flashlight and it uses 2 9 volt batteries. It has 2 settings, bright and brighter, and it is bright but it eats 9 volt batteries like a teenager at a cook out, even when the flashlight is not in use. With these batteries I am happy to say that they are still going strong after all this time from delivery until today 3/24/2021. So the extras that I bought I am going to install them into my smoke detectors at home. Excellent product, now if these guys would just make car batteries...

Update and Upgrade. These 9V batteries are easy to charge and they hold a charge for a long while. Despite one bad battery from a group of four, I was too harsh in my original review.= = = = =Just got these batteries. They charged quickly. No instructions. Very happy with Amazon after I contacted them. Not so sure about the quality control of the BESTON factory. My ZTS battery tester thinks that these BESTON batteries are only operating at 80% which is fine since they're only 8.4 volts - which is fine. I may do a follow up review later.

These batteries come with no instructions, so you don't know how to charge them properly. In my case, I plugged them into chargers, and a blue light came on. I had no idea what that signified, but after charging for four hours, the blue light was still on, and the batteries were cool to the touch, I knew the charging source was working properly, so did the mean that the batteries were defective? No, apparently not. Other people on Amazon said the blue light signifies that they are fully charged, so I guess that all's well--so far, anyway. Life would be so much simpler if manufacturers would just include manuals/instructions.

I wanted a set of 9-volt batteries that could be recharged, but I didn’t want to buy another charger just for this style. I already had an 18650 with built in micro-USB charging, so I wondered if the same thing was available in 9V. I found these, but I was concerned about the size. Would these fit in the same compartment that my alkaline 9Vs did? So I asked a question here and the answer I received was a positive one. So I ordered them. I have been very pleased. They do fit in the same compartment as the alkaline 9V. I cannot speak for capacity, but they do power what I bought them for, so I am pleased.

I WANT to like this product, I really do. In fact, for the right applications, it's great!However, there are two major limitations and one MAJOR problem that I've found with this product.First: Be aware that this is NOT A 9V BATTERY. Internally, this is a 2S Lithium Polymer battery, which means that its nominal voltage is 7.4V. Fully charged, this works out to 8.4V, as shown above. This means that if you have any voltage sensitive devices, they might misbehave and any battery gauges will DEFINITELY be wrong. Most devices meant to run off a 9V battery should still work just fine, though, and once under a heavy load, these batteries will not sag nearly as much a traditional alkaline 9V. Honestly, I was expecting the circuitry to boost the voltage to 9V, but there is NO boost circuitry (boo!), so you get the raw 6-8.4V of any other 2S LiPo battery.The second issue isn't really the fault of the manufacturer so much as Physics. Traditional 9V batteries are all pretty lousy, to be honest. This battery is much happier under heavy load than alkaline batteries, which is great for my needs (running Arduinos with motors, etc). However, this can be a double-edged sword. These batteries ARE protected, so they will shut off power once the battery voltage gets too low (to protect the batteries from damage). With a CLAIMED 650mAh of charge(more on this below) , this runs out VERY quickly. In short: the battery can function extremely well under high drain, but as a result it runs out of energy faster than you may be accustomed to.Again, this isn't really a PROBLEM, just something to be aware of.No, the PROBLEM is that the capacity itself is a blatant lie. It claims all over the packaging that it is a 9V 650mAh battery. This might lead one to think that it has 9 * 0.650 = 5.85 Watt-hours of energy available. That would be GREAT!One problem: It doesn't even come close to that. Being the curious type, I opened the battery where I found things to be in fine order-- there is a microcontroller running a pretty standard 2S protection board (with no boost circuit for 9V-- darn). But when I checked the individual LiPo cells, they gave up this battery's dirty secret:They do not use 650mAh cells. The cells used are clearly marked as 500 mAh.When you combine the lack of a 9V output with the blatantly false capacity, these batteries DO NOT give anywhere near the 5.8 Wh. Going by the cell's own marking, they only contain 1.85Wh each, for a total of 3.7Wh.That means that these batteries contain LESS THAN 2/3 of their advertised energy.I understand that different battery chemistries have different nominal voltages, and if they batteries delivered on the 650 mAh promise, I'd be inclined to let the energy discrepancy slide (we'd still be getting almost 5Wh in that case). After all, 9V NiMH batteries have the same voltage issue!But these batteries don't deliver on their promises.The 650 mAh is a direct and blatant lie.No wonder they run out of steam so fast.Look, the batteries are not bad. They look well built inside and out, and (while not an expert) I don't see anything super alarming in the circuit board-- The batteries are set up for balance charging, and shorting out the terminals will trigger the short-circuit protection as you'd hope. The battery can put out much better current than a traditional alkaline battery, and the charging (while slow) works very well.If these batteries were just *honest* about their true specs, they'd really be excellent and they'd be easy to recommend. Instead, I've got a sour taste in my mouth.They're good batteries, but I still would look for a more honest manufacturer.

A lithium 9V battery that can be recharged with a common micro usb cell phone wire! I have an Oden? brand Lithium 9V battery and it is over 10 years old and still works great. I charge it once every few years so I know these lithium 9V batteries can last a very long time.Also, this DMM has no auto-off like many MM's which is a shame and neadlessly results in dead 9V batteries. Now you just recharge the battery! I bought a 4 pk so I can just swap in such a situation.Also, NO LEAKING ACID! Traditional 9v's leak after a few years and ruin the device - that's an expensive battery once you need to replace the device!Keeping this 15 year old multi-meter out of the landfill!

I use these batteries in the construction of Tron Identity Discs and have loved their rechargeable function. It's so much easier to wire in a micro-USB port than to have to disassemble when the battery dies like I would have to with a traditional or regular rechargeable battery. I've shipped about 50 of these and other than one showing up completely discharged from being in transit in sub freezing weather have heard no complaints from my customers.

They came faster than expected.. they last for a long time. I use them in my garret metal detecting pinpointer... dont have to buy a bunch of batteries anymore..save a lot of money..will definitely recommend..