Rechargeable 9V Lithium Batteries - 13500mWh Long Lasting LI-ion Batteries with Micro Charging Cable - Quick Charge in 1.5 Hours, 9 Volt Battery f...

I got a 1-pack, so I can't comment on any split-cable that might come with a multi-pack. This battery hits several points I'm after these days. I prefer my batteries are: (1) rechargeable, so I don't have to spend a ton and throw away a ton for the same job; (2) lithium, so they have the same voltage as alkaline (usually 1.5 volts per cell for alkaline and lithium vs. 1.2 volts for many other rechargeables) and so the voltage doesn't slowly decrease, but stays high until tapering faster on the tail end (necessary to keep some electronics working okay); (3) made with an integrated charging port, so I don't need to keep track of yet another specialized charger; and (4) with a USB-C port for a similar reasonnot only is it the latest kind of charging port, but then I don't have to keep track of as many cable types. In addition to hitting these 4 points, specifically this 9V battery seems to work fine in my fire alarm. Some manufacturers have advised against using lithium batteries in fire alarms in the past, but there's a lot of confusion in this area. From my amatuer research, here's what I've learned. Many fire alarms are sold with integrated, non-rechargeable lithium batteries and are sold as 10-year alarms. Fire alarms themselves are supposed to be tossed and replaced every 10 years since their detection components degrade, so there's no reason to replace the battery if it lasts 10 years. But you shouldn't really expect even lithium batteries to last 10 yearsunless they're rechargeable and being recharged. Why might a manufacturer advise against lithium batteries in fire alarms? This seems to be connected to their "sudden" voltage taper at the end of a discharge. But practically, in a fire alarm, this means you should expect about two weeks' worth of chirping in an alarm that isn't also tied into AC power. That's as opposed to months' worth of low-battery chirping from other types of batteries. So the only circumstance in which I wouldn't recommend rechargeable lithiums would be where your alarms aren't also AC powered, you don't regularly change the batteries before they fail, and you're away from the location for months on end. Change any one of those variables and I personally think you're better off with rechargeable lithiums. What I've said isn't very specific to this particular battery, but I will add that I've had a harder time finding USB-C 9Vs like these. Be wary of all those out there that are micro-USB instead at this time of writing. There's no big problem with those (I have some of those, too), but I find it easier to try to keep mostly USB-A-to-C cables around for charging miscellaneous household electronics.

So the jury is still out on how long rechargeable 9V lithium batteries will last in smoke detectors, and if one brand is better than the others. Here are the numbers... Energizer Ultimate Lithium 9V Battery which seems to be standard, and is my preferred, has 1000 mA continuous discharge. Do an internet search for "Energizer L522 Datasheet". I prefer the Bump 9V rechargeable as it feels solid in build, but it still has that strange light weight associated with Lithium ion batteries. The TQTHL 9V Rechargeable battery claims 13500mWh, which is 1500mAh at 9V, but the voltage varies over time, and using mWh feels like a marketing trick. The product feels like it is half baked, as the product description and manual have contradictions and discrepancies, and the housing feels cheap. Shortly after I received mine, it is listed as "Currently unavailable". I believe some companies are using ZeeBooth Vine for QA testing of unfinished or prototype products. Searching ZeeBooth, you will find 9V lithium rechargeables from 600mAh to 1300mAh, so by the numbers, the rechargables should put out as much energy if not more than the Energizer, but the problem may be holding charge over 10 years, which the Energizer Ultimate Lithium batteries claim. I have found that to be true in my experience with the Energizers. Rechargeable batteries usually do not hold their charge over time. So if you need a 9V battery and find a dead one in your device because you didn't properly turn it off or you just got a bad battery, any of the 9V rechargables will help you in a pinch. Back to this battery... the charge time is as expected, and the light was green as described, and the devices I tested it on did not show any low battery warnings when fully charged. In other words, no major surprises. I am a big fan of the Energizer Ultimate Lithium 9V Battery , but I am not going to pay $12 for a throw away, when I can get 2 rechargables for the price of one of the Energizer 9V. However there is a question of longevity for any 9V lithium rechargeable, and in a smoke detector, you might not want to stick with the Energizer. More smoke detectors are coming with built in lithium ion batteries, so I don't really consider this an important consideration, as there are many other devices that are within a hands reach that use 9V batteries. PROs: + Rechargeable + Lithium + USB-C + Light weight CONs: - Feels cheap - Hokey marketing using mWh - Half-baked

Carbon-zinc and Alkaline 9 volt batteries are very expensive when compared to single 1.5 volt battery cells and fortunately they are not used in very many battery powered devices. They make up less than 4% of the Alkaline battery market. They are made up of 6 single 1.5 volt cells connected together in series which probably explains their cost. PP3 is the common package with polarized snap connectors on the top. When 9 volt batteries are required, their task is usually very important. They are often found in smoke detectors, sound effects pedals for musicians, garage door keypads, Multimeters, walkie-talkie's, transistor radios, data recorders, and portable medical devices. Lithium-ion rechargeable 9 volt batteries are a fairly recent development. These give full voltage as they discharge right up to the end with an integral voltage controller. Then recharge and use it again. They are rated at 600 to 1500 recharge cycles. The TQTHL 9V Li-ion Battery is rated at 13500 mWh at 9v = 1500 mAh. That is one of the strongest 9 volt Li-ion rechargeables that I have found. Quick Charge in 1.5 Hours. 9 volt stabile output with integrated charge and discharge controller. I have tested this with a Fluke 27 Multimeter and is shows 9.12 volts DC after fully charged. I have installed it into our garage door keypad for further testing. So far it is working as well as the 9 volt Carbon-zinc battery that it replaced. I plan to buy more!