Tenergy Centura 9V NIMH Rechargeable Batteries, 200mAh Low Self-Discharge Square Battery for Smoke Alarm/Detector, 2 Pack

I have a clock radio that uses a 9v battery for backup in case of power failures. When the power goes out the clock display shuts off to save power but the battery allows it to still keep time and if your alarm is set it will go off as usual. The clock has a low-battery warning light to let you know when to replace (or in my case recharge) the battery. I was using one of the first old style NiMH 9v batteries that was not low self-discharge that had a 150mah capacity and I think around 7.2v output. When it was fully charged and I put it into the clock radio it would take literally 3 or 4 seconds for the low battery light to come on. Obviously the battery didn't have a voltage above the threshold of the warning light so it came on immediately and stayed on. The battery did have enough power to run the clock if we lost power which was good, but it was annoying that I didn't have any way to know when the battery was drained. I found out through trial and error that the battery would only last about two or three months due to it self-discharging over that time. And that was without any power outages. So I went with this new low self-discharge 9V battery to see what would happen and couldn't be happier. It has a higher voltage so now the low battery light stays off (at least so far). I ordered these along with the Tenergy TN141 2 Bay 9V Smart Charger for NiMH 9V Rechargeable Batteries and gave the battery a quick charge to top it off before use. It has been about a month now and I just picked up the Delkin Devices DD/BATTEST MULTI RoHS AA/AAA Battery Power Tester and checked the charge level and it's still showing a full charge which is excellent, the old battery would have already been down to around 50% charge at this point. I will use the battery tester on it again when the low-battery light comes on, I may be able to use it for a while after the light comes on depending on it's charge level at that time. Over time as my other 9v alkaline batteries fail in my smoke detectors and other devices around the house I will definitely be replacing them with these. There really isn't any reason to stay with standard alkalines batteries over these new low self-discharge type of rechargeables anymore, with a few exceptions where rechargeables just aren't a good option for a particular device. But for the majority of our devices these are the way to go, saving us a lot of money over time. Using these batteries is most likely going to eliminate having to ever buy alkaline 9v batteries again since each one can be recharged up to 1000 times. That's a nice chunk of change saved right there. For each of these new 9 volts you bought you would be saving 1000 times the cost of a 9v alkaline, which even if they sold for only a dollar apiece you would save $1000! That's absolutely ridiculous. In a "I really like that" ridiculous kind of way! These modern low self-discharge NiHM batteries are another small but helpful innovation that makes our lives just that much easier. Highly recommended. *** Update Sunday, June 10, 2012 This discussion got me wondering, when using NiMH low self-discharge batteries, just how long would a smoke detector give you low battery warnings, until the batteries discharged completely and the warnings stopped? I had a Kidde NightHawk combination smoke/CO2 alarm that I could test with and like a lot of newer alarms it takes AA batteries, so I tested some Imedion AA low self-discharge NiHM batteries (three). I discharged the batteries until they were down to about 25% full, put them in and then had a long wait until I heard the first low battery warning. The alarm manual stated that using alkaline batteries the low battery warning would last at least seven days. I figured that the way these batteries discharge quicker than alkalines at the end of their life that the warning time would definitely be shorter than seven days, maybe around 2 to 5 days. However, what I found was the complete opposite! To my great surprise I actually ended up stopping the test myself before the batteries were completely exhausted. Why? Because the alarm gave me constant low battery warnings FOR THREE FULL WEEKS. I really didn't need to see just how much longer they were going to last past that. So apparently the low voltage cutoff point that triggers the warning was high enough that the NiHM LSD battery still has sufficient voltage to keep the warnings going for a long time, before it hits the steep (and quick) drop off point. So maybe a NiHM LSD 9V battery like this Tenergy might last longer than you would think as well, depending on the device used. Maybe we'll hear about how a 9V battery fares from someone in the future, either on Amazon or posted elsewhere.

I own a lot of NiMH batteries ... mostly AAs & AAAs, but I do have a fair amount of C, D and 9V. Before I give my review, let me state the importance of having a good quality Battery Charger. I typically use a Tenergy T9688 Battery Charger & I have an identical C. Crane-branded model as the T9688. If you don't have a decent charger, you won't get satisfactory performance from ANY NiMH battery! Choose a charger that (1) Reconditions batteries; and (2) Can identify batteries with bad cells that need to be discarded (recycled). I have found these Tenergy LSD Low Self Discharge 200 mAh 9-Volt batteries and the [regular] Tenergy 250 mAh 9V to be the best 9V NiMH batteries that I have used. Both retain a charge for a long time - especially these LSDs. As an example I've switched over all 7 of my home's smoke detectors with a mixture of both and I've found them to be reliable and durable - nearly the same life (before needing a re-charge] as throw-away Duracells. I would not use these in something as important as smoke detectors if I did not have complete faith in their performance! And since they are Green/re-chargeable, you save money within a short period of time & help the environment. Note: If you do use these in Smoke Detectors, just ensure you have a few spares to replace a "chirping" smoke detector battery when they get low and set-off the Low Battery chirp/alarm.

I purchased these before a few years ago...and they still work great to this day, after being charged many times. I need a few more 9 volt batteries so I ordered another set. They came almost fully charged and worked perfectly in my devices. I look forward to their slow discharge rate as they are in devices that don't receive regular use. Definitely worth picking up..they pay for themselves in just a couple charges! UPDATE - I had one battery stop taking a charge a few months after purchase. I emailed the seller, but they told me I had to go through Amazon (which was past the return period). Then I e-mailed Tenergy directly asking about their 6 month warranty as described here. Then I got an e-mail from seller saying that it is a 90 day warranty. A few e-mails later, I finally got a replacement battery sent out for free. I was told it was a "one-time" courtesy...which was not really a courtesy considering I was still within the warranty period. As others have mentioned, customer service is not very good with this product or company. J

I bought my first of these a long while back. And I wasn't impressed initially. The battery felt light for a 9v, materials felt cheap. But happily a long while later, I've been pleasantly surprised. These rechargeable batteries hold a charge for a long time. I originally bought them for Rocksmith. I don't play the game much but had bought a cheap acoustic electric to do so. The pickup like most of them do require a 9v battery. I popped it in and even over a year later, the charge was good. I recently had an issue with a smoke detector. The 9v Duracell batteries I'd bought for them originally-- by the time I had to use them, they were long expired and like 3 years old. It didn't occur to me that they'd run out of juice before I even got a chance to use them. I pulled the battery from my guitar which hadn't been used but three or four times and was months... think like 18 months since I last recharged. They held the charge well enough that it's been over a week in my smoke detector and it's still not beeping low battery. I've long since charged a backup but it may be a long while before I have to swap them. I'll be using these as my replacement and backup 9v batteries from here on out. Even if they run down in between 3 or 4 year swaps, I can recharge them-- and I just don't believe they would take longer to drain than sitting inside the smoke alarm/detector.

work good

I have been using these in mics at my church for about 18+ months without issue. They only last about 2 hours, but that is in a high drain wireless microphone, so I wasn't expecting much more from ANY rechargeable battery. I have read many reviews that a lot of rechargeable 9v don't work very well in high draw/drain equipment, but these work great in our mics. I rotate the batteries through the mic and charger, so I always have some that are at a high charge to swap out for each service. I have not had any issues with them fitting in any devices, so these seem to be a standard size (Another issue I read about in reviews was batteries fitting too tight or too loose). The only issue I have had is the plastic wrapping on each battery is starting to crack or peel off a bit around the edges. I don't believe it would affect the actual usage of the battery, since it is just a thin plastic wrapping with the label on it and there is hard plastic (The actual battery) under it. But after almost 2 years of weekly use, I would expect some ware and tear on them.

Positive:These work just as advertised. These seem to be high quality. Some earlier Tenergy batteries were not. I have to point out that these are the Low Self Discharge versions because these are much better than the originals. They do not go dead waiting for you to use them and they will work in something like a smoke detector, remote or sprinkler timer. All of those devices have long periods of time where there is little or no draw. With a sprinkler timer they have to provide full power for a couple of seconds a day and they spend the rest of their lives with no draw. Normal NIMH batteries cannot hold a charge for more than 2 months even if unused. These can. Similar situation with many other things. Since 9V batteries are costly these can save you quite a bit over time. They also cut way down on the amount pf recycling or disposal needed. You also don't run out of batteries and have to run to the store. Negative: If there is one it is the higher cost of the batteries and the cost of a charger. Do the math. It is way worth it. Go for ti!!

I have 12 of these for use in smoke detectors. Two won’t charge in the Tenergy charger. When I contacted customer support, they argued the my battery tester was not accurate. How about the fact that they make the smoke detectors chirp and the battery charger throws an error? Absolutely terrible customer service. One other thing to note, six of my batteries are 10 years old. They still charge fine and seem to last in the smoke detectors for about one year before needing charged. Our detectors are hardwired with battery backup. These batteries don’t have as many amp hours as others but work fine. Product is is pretty good. Customer service is awful. PS - I never had an issue with the battery tester.

se recargan rapido y su resistencia y duracion genial se las recomiendo a un excelente precio

Bonnes piles durables

I tested these at a constant current draw of 50mA, discharging to 6.3V, and....drum roll.....they slightly exceeded their specification!! :) I measure approximately 210mAH, which exceeds the specification of 200mAH. THANKYOU Tenergy for being honest with your specifications. This is an initial review - I will update later if I have anything more to add, after I have used them.

These cost about 4x as much as regular (disposable) 9v batteries, but will pay for themselves if you use them in anything that requires them to be recharged just 4 times. Being low-self-discharge, they should last a year in low drain devices. I'm using them in smoke detectors, and they are working well. I'll recharge them every 6 months or so, since I was going through alkalines about every 6-12 months. I expect these batteries should last about 10 years, based on previous 9v rechargeables I've used, so in the long-run I'll save money.

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