should i buy 4 pces of 9V 250mAh reviews

Features and Benefits * High quality 9V rectangular size rechargeable Nickel Metal Hydride (NiMH) battery Ultra high capacity of 250mAh * Exact replacement for standard 9V rectangular size battery * Provides very long use time per charge with this high 250 mAh capacity * Advanced Ni-MH technology means much longer use life per charge than the ordinary rechargeables * Designed for enhanced performance for high drain applications such as: R/C controller detector transmitter paintball guns and other portable high drain digital electronics * Can be recharged for up to 1000 times providing big saving by replacing hundreds of expensive throw away 9V rectangular size batteries. * Convenient operation without memory effect. Can be charged anytime. * Can be rapidly charged with our chargers model BC1HU V1199B V3969A1 V228 T6278 T2299...etc. * Dimensions: (H x L x W): 48mm x 26mm x 16mm. * Weight: 0.1lbs per cell * Battery tested based on International Electronic Commission (IEC) standard to ensure capacity quality and life time The performance of these batteries has been surprisingly good! I've been using them for almost one year now. I use them in a set of Shure wireless mics (see my review of the mics on Amazon.com). They have been doing an outstanding and demanding job. Their capacity is very good. Additionally, I feel environmentally green by using rechargeable battery. They pay for themselves after few recharges easy. I've been very happy with this product. Highly recommended. They came charged and the spec's look good. I have used them now only a few weeks, but they are holding a charge as well as I'd expect. I'll report later if they disappoint me. For now though, I'd recommend. I use them for my DVM and other electronic devicesI bought two of these Tenergy 9V's for the smoke and carbon monoxide detectors in my kitchen (they came as part of a set: . I got fed up with the frequent replacement of alkaline 9V batteries. They'd last a month or two, then the alarm would start chirping annoyingly to indicate the need for replacement. Then I'd have to stand on a chair and tiptoe precariously to reach the ceiling mounted alarm and fumble with the cover.

Not being a well-known brand, I was unsure whether I would be able to rely on Tenergy. But after 8 months of using these and the other sizes, I am pleased with their performance and bought 12 more 9V's for the other detectors in the house and a TENS muscle relaxer. It has been at least 4 months since I inserted the Tenergy batteries into the detectors and they haven't needed recharging yet, so I am quite pleased with their life and energy capacity.

Their price to performance ratio is hard to beat. A regular alkaline Energizer at the local CVS is $5. They can only be used once. These can be recharged hundreds of times, making them very cost effective. (Tenergy claims up to 1000 charges, but real world performance will be a lot less).These are not good batteries. I bought 4 of these a couple of years back. Recently, two of these 4 stopped accepting a charge. My charger [Tenergy T-3969A1] won't even recognize them when inserted into the charger [charging light wont come on]. I researched into this issue on the `net and found out that sometimes the batteries get an open cell. I have not tried the revive methods suggested by some people on those two batteries.

At that point I suspected that the charger went bad so I bought a Maha Powerex MH-C490F Stealth charger. That charger also refused to charge the two bad batteries.

However when I tried to charge the other two batteries... both exploded after about an hour of charging. I suspected that the batteries cannot handle the fast charging action of the Maha MH-C490F charger. Did some research again... found out that the Maha Stealth is rated for 70-90mA. For comparison, I looked at Tenergy's own 9v charger - TN141. That is rated for 100mA. Also on Tenergy's own website says "Can be rapidly charged with our chargers model TN141, TN136, TN137, BC1HU, V1199B, V3969A1, V228. "

Hence it was definitely a bad battery and not the charger which caused these batteries to explode
OR, although these are listed to be capable of rapid charged, in reality, these batteries cannot be rapidly charged. These can be charged only by those old style chargers which put out only 15-16mA like the Tenergy T-228 or T-3969A1.

Interesting point:
The 2 batteries did NOT explode spectacularly; they cracked and the tops popped out. After looking closely I could see that 2-3 of the 8 internal cells had swelled up and leaking fluid. We use these for our lavalier mics and a few other things that take 9v's and they've been perfect for what we need. Well worth the $'s we spent on them, considering how many times we've charged them and would have thrown another 9v alkaline in the landfill. After three months 25% of the tenergy 9v batteries experienced a catastrophic death with cell swelling. Battery was not exposed to any extreme conditions. Surviving batteries performed well. I bought these batteries to use in my bass guitar with active electronics, a battery eating monster! The extra capacity of these batteries insures I don't run out of guitar before I run out of music! I have bought several batteries from this brand. They are great I have others alredy working for 2 years and I keep recharging them. I had missed the square one and now I had them for a month and they work great. The thing to look for in batteries is how much capacity they have the mAH part. The more mAH the better. I got these to use on a garage motion detector and they work okay, but if you get a lot of movement, these batteries don't seem to last too long. At least they're rechargeable though so I've done that a few times already. They may work better on other devices that are not constantly turning on and off even though it's just an LED on the sensor. while these batteries charge quickly and are relatively inexpensive, they do not last as long as normal 9V batteries. A good idea if you have opportunities to swap batteries, but a bad idea if you need these batteries to last 6 plus hours at a time. These batteries are long lasting (can be recharged many times), last for a long time and have a high power density. I bought 4 of these three years ago and they are used hard. Three are still working the fourth was destroyed by accident. So when I needed more I bought the same ones.