Powerex MHR9V 9.6V 230mAh 1-Pack Rechargeable Battery

Quite simply: TOP POWER!! This 9Volt, (actually 9.6 Volt), battery holds it's charge nicely and powers a MIDI Controller keyboard for longer than the original 6-AA battery array (that was the original configuration). I figured that, after the 6-AA holder broke and, seeing as how the keyboard was old enough now that no replacement parts for it existed, I added up the 1.2 volts x 6 AA batteries and came up with 7.2 volts. I knew that a lot of people complained that many 9V batteries were only 7.2v to 8.4v, and that this POWEREX was a full 9.6 of honest, unadulterated power. As long as your intended device(s) can handle the full 9.6V, I highly recommend this battery. It is awesome. At under $12 apiece, it might seem expensive, but for you you get, trust me, it is worth every penny. All other 9V rechargeable batteries are inferior.

9.6 volts. Great stuff. Initially I purchased other brands of rechargable batteries for some electronics I have which call for 9 volt batteries, but they didn't even power one of my items. This is because they are rated for something like 8.4 volts, and I was told that it may be even lower. These work great, and this company has some really nice chargers as well, which charge in around 2 1/2 hours and automatically switch to a trickle charge to avoid overcharging and to keep the batteries optimally charged. I didn't see it here, but I found a 4 battery charger which is perfect for my needs.

Ok,I just purchase 6 of these and they are not bad, but you need to be aware of a few things:1) The first charge of these batteries will be fantastic; on the first charge these batteries will run for as long as their aklaline cousins.2) It takes at least 3-5 charges (5 in my case) for the batteries to even out. At that point, they are hold approximately 20% less energy [run time] than an alkaline battery.3) When fully charged, these batteries will have a charge of at least 12 volts; 9.6 volts is what they advertise, and what you get is 12-13 volts. It's possible that a voltage sensitive device may not like this.4) I have a device that uses 6 - 9 volt batteries, and it runs for 3.4 hours on these batteries. Other brands deliver 5.2, 7.6, and 10.6 hours respectively. The middle range (7.6 hours) is also a rechargable battery.5) Completely discharged batteries that AT LEAST 2 HOURS (120 minutes) to charge, and average about 140 minutes.They are OK.Personally, I'd think the best option is the PowerEx IMEDION low self-discharge version of this battery.

I speak with the use of an electro larynx. When a battery goes dead, I'm left speechless. Because the Maha PowerEx is more powerful, I can set the volumn level down, which helps it hold a charge. And it holds its charge longer than the other brands and models I've tested. I'm sticking with this one.I gave it 4 instead of 5 stars because the case has come off. I don't know if this is dangerous. I just slide it back on and go on with my business.And another issue common to all the batteries I've tried: they will burn out and melt down in my pocket. Ouch! And I've not been able to find a convenient carrier made for these guys. My solution--I don't carry spares, so I appreciate the longer charge life of this model even more. I'm going to order more of these.

I use four of these 9V 230 mAh batteries in my model railroad wireless throttles. They consistently outperform their Energizer counterpart and quickly recharge. I tried the Tenergy Centura brand and the plus terminal popped off before I ever had a chance to try it out!I am happy with the Powerex brand.[Update: Of the original four Powerex batteries I bought in Feb. 2009 two will not recharge. Five year life span is OK with me.]

I use the 9 volt powerex charger to charge these batteries, so there won't be any incompatibility issues.However, I have had 2 out of 3 batteries die on me after 8 charges. There is a manufacturing defect in these batteries.

I was so hopeful that these batteries would work. We used them to power cordless mics at church. Other reviews I had read online said they worked well, but after only 2 1/2 months we started to have trouble. We use an average of 5 batteries per service so I purchased a MAHA smart charger and a total of 10 batteries to be cycled from week to week. 2 services on Sunday and a Thursday night practice is 3 uses per week times 2 1/2 months = about 39 events. We only used 5 per event, so thats a total of around 20 work cycles per battery before I started experiencing problems. The problems were batteries dying after only about 10 minutes of use. The MAHA "smart" charger started blinking fault codes also.If we can create cell phone batteries that can last years and many many work cycles why not a 9v?

This battery is doing a great job for me in my smoke detector which i had to put a new battery every 28 days...I put this battery more than 30 days ago and in my smoke detector and still working good.