Powerex MHR84VI Imedion 8.4V 250mAh 1-Pack Rechargeable Battery

I chose the 8.4V version of this battery since the voltages seen by this battery are closer to the voltages seen by alkaline batteries --- When charged I am typically seeing 9.5 - 9.6 volts from these cells. The 9.6V version of this battery will see voltages when fully charged that I just don't trust in my expensive test equipment. It is also important to keep in mind that even the rated 8.4V is plenty of voltage to power most devices, a 9V battery is not considered "dead" until it hits about 6-7V. One advantage of NiMH rechargable cells is that they will maintain a relatively high voltage until they are dead (and it is a sudden drop when they run out of energy). Alkaline batteries start at a higher voltage and then gradually drop in voltage through their entire use. Will this battery last as long as a disposable alkaline? Pobably not. Energizer 9v batteries are rated for 625mAh, these batteries are rated at 250mAh -- Just keep in mind that these batteries will maintain a steady voltage for the entire 250mAh, the energizer will not maintain voltage for it's entire 625mAh. I think in many devices, you will see about half the capacity per charge from these vs. a disposable alkaline, depending on the device your results may be better.My reason for using rechargeable batteries in this equipment is not so much based on the idea that I'm saving alot of money, it will take me some time to actually see a cost benefit from this purchase... I chose to replace ALL alkaline batteries in my expensive devices with low self discharge (LSD) NiMH batteries based on the fact that these batteries will not leak like alkalines can if left in equipment over long periods of time, I use Eneloop cells for my AA and AAA needs and have purchased both these for my 9V uses. Just one prevented battery leak in my equipment will pay for the switch to these batteries, the ability to reuse them is just a bonus for me.

I recently purchased several different Hybrid NiMh batteries and performed simple current and voltage tests. Nothing as elaborate as some of the testing I have seen reported on-line by other reviewers, but enough for me to get a sense of the performance of different brands. Of the three or four different brands I have looked at, these Maha batteries are absolutely the best. The manufacturer claims they are rechargeable up to 1000 times which is at least twice as much as the other brands I have seen. Haven't had mine long enough to know if this is true, but based on their superior performance so far I tend to believe the claim.This battery is available in both 9.6 volt and 8.4 volt versions. I first purchased the 9.6 volt battery thinking that this would work better in my electrical meters because it would maintain closer to the approximately 9.5 volts that a new alkaline battery for which the meters were designed would put out. However, it turns out that when fully charged, the 9.6 volt Imedion puts out 10 to 11 volts under light load. This probably makes it a great choice for devices that draw a lot of current. I decided to try the 8.4 volt Imedion in my meters which have typically low current draws, and, indeed, they maintain their voltage in the 9.0 to 9.75 volt range when freshly charged.

Purchased two Imedion batteries, using them for for my smoke detectors, the last charge was good for more than 6 months. The Powerex batteries I purchased previously did not last.

I previously purchased several of the older Powerex batteries. They each stopped working after less than 10 recharges.I purchased this newer version in the hopes that they've improved, but I ran into the same problem. After less than 10 recharges, the batteries no longer hold a charge.All were used in a low-drain, room temperature environmentAll were charged on a Powerex C490F chargerI've gone back to using alkaline 9V batteries, which are far more cost effective for me

Doesn’t work with my old machine (connectors are shorter)

I've used this brand for 3 1/2 years in wireless microphones and they work great. They do seem to stop holding a charge after about 2 years, but I estimate that I get about 100 recharges out of them before they die.I use them in a public place with a lot of other people, where it's easier to keep them on the smart charger all the time, rather than trying to keep track of which ones need to be charged versus which ones just came out of the charger. I know it's bad to leave them on the charger, so if you take better care of them they may last even longer for you.

This battery works fine but the duration of battery life is not significantly better to justify the extra cost!!! If you can find them at a discount, they would be worth buying.

Excellent 9 volt batteries. I previously had the 9.6 volt batteries and had some issues with charging them as the charger would refuse to show them as charged when they go over some predetermined voltage level. I had to use an older charger for those batteries rather than the compact charger I bought from Amazon. In terms of actual voltage when charged they end up around 9.3 to 9.4 volts and they last longer under my usage than the Tenergy batteries I also have.