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 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.

9V batteries have long been the Achilles heel of rechargeables... but these seem to be a good match for most uses at a good price. They are about 8.4V instead of 9V proper, but should be close enough for nearly all devices, and may even maintain a working voltage LONGER than disposables. The current rating is also lower, but I've had several working just fine in my smoke detectors for months without trouble. At this price, they'll pay for themselves after less than 10 recharge cycles, and the hundreds of recharges after that is just free money... I got tired of hoping 9V batteries would just go away entirely, and the inconvenience of going out to buy new ones as soon as my smoke detectors started to beep. Having a few of these on hand is infinitely more convenient. The low self-discharge (LSD) means they'll work just fine in long, slow power drains like smoke detectors, where NiCDs or older conventional NiMH do a poor job. For higher-drain devices, Tenergy also sells Li-Ion 9V batteries with double the capacity around here. But these are the better choice for low-drain devices, and shouldn't be "bad" no matter how you use them.

Compatible with my charger, easy to use, holds charge and cost effective vs regular batteries.

super performing 9 v batteries

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 was rather surprised to measure 9.0 volts right out of the package. But I decided to charge the batteries anyway just to see what a fresh charge would do. Both batteries measured 9.9 volts under load on my voltmeter. My voltmeter has a load test, but I'm not sure how much of a load it provides. However, it is enough to load down an alkaline battery somewhat. I am using these batteries in two wireless microphones for a Karaoke system. The microphones prefer a full charge and one microphone won't even work if the voltage drops much below 9.0 volts. So I've learned that I have to recharge these batteries before each use. I wish the batteries had a larger power delivery life than 200 mAh. These batteries look tempting as well: Combo: Tenergy TN347 Smart 2-Bay 9V Li-ion and NiMH/NiCd Battery Charger + 4 pcs 9V 500mAh Li-ion Rechargeable Batteries .

They look nice and they work just fine in my smoke detectors. But what good are expensive, rechargeable batteries if the connecting tabs pull off when you try to remove the batteries from your device? They become very expensive one-time-use batteries. And on top of it then you have to get out your tools to get the connector out of the device before you can put a new battery in it. You might be ok with these batteries if all of your devices just use contact pressure to make the electrical connection but if you use them in devices that have connectors that friction fit together you might find the connectors on the battery stay in the connectors in your device instead of attached to the battery where they belong. Great idea but an exceedingly poor design make these batteries a throw away item long before their useful life should end. Update Nov 2020 - 7 years later and these are only holding a charge for about 2-3 months. I was constantly changing the batteries in my smoke detectors until I got to the point that I just went out and bought some alkaline batteries to replace these. So the advertised number of recharges is nowhere near what I got. Still they did last 7 years so when I figure out their cost vs how much alkaline batteries would have cost over that same time frame they come out cheaper in the long run. Adding a star because over the long run they're cheaper than alkalines, assuming you don't lose too many to the connectors pulling off.

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

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.

Por su precio están bien Duran al rededor de 4 horas

Perfect

The batteries appeared to be of good quality (6-cell 8.4v type). It arrived precharged at around 75%. I've done a rough drain test, with a top up, they can deliver a full 200mAh as stated. Only small surprise is that they arrived in a single bubble bag with terminals exposed (not individually wrapped), don't think this is a proper way to ship precharged batteries.