PowerexLow Self-Discharge Precharged 9V(9.6V) Rechargeable NiMH Batteries (MHR9VP), 1-pack

Works on my (ancient) Empi Tens unit, although it's a bit thick.Since you can't get the actual Empi batteries anymore, these were about the only ones that I came across that had the right voltage and were close enough in depth to actually work in the Tens case. And, they do work. I did have to move the little fabric battery pull in the tens battery compartment out of the way, but after doing that, they fit without a problem. And, the PowerEx charger is much better than the original EMPI tens battery charger, so I expect these batteries will hold up better than the Empi ones did over time.

The media could not be loaded. these are the batteries that you can depend on, i purchased several powerex batteries and i used them to power my eton field radio and they are very reliable, doesn't drain fast and if I may suggest use the powerex mh c808m charger designed to charge d cells, for quite sometime these d rechargeable batteries were out of stock finally amazon replenish their stocks and iwas able to order several packs of these batteries, low self discharge rate is added feature since the radio that I am using them with consumes a lot of batteries, somewhat pricey but I believe they are worth the investment in the long run, a much better alternative for alkaline batteries which are quite expensive and sometimes, they leak which will damage your equipment.these batteries are quite hard to find and different stores do sell them but with added costs, sometimes you will be charged with the shipping, almost one third of the cost of batteries. amazon ships it for free most of the time. I do hope that amzon will re-stock the mh c808m and the powerex 100 minute cool chargers,grateful to powerex and amazon for leveling the playing field!

I like the 9.6v flavor for the CO detector back-up battery. Hard to tell if it will prolong the day you get the low voltage alarm from the CO detector (which always seems to happen when it's the coldest in the house... like 4am of course) any better than the 8.4v flavor (which has a bit higher capacity). At rated voltage (which is not a constant voltage over the usefull operating range), the power available is about 18% less in the 9.6v battery (they stuff another cell in series - 8 instead of 7 - so each cell is smaller and I'm guessing the extra packaging must eat up some space as well). I'm just going with the higher voltage but don't know if it's better than the 8.4v battery or not. But, what I do know is, I am done with alkaline batteries which leak and damage equipment; goes for AA and AAA cells as well. ALL alkaline cells will leak given time. As a side note, I've had the best luck with eneloop AA/AAA NiMH cells. Can't find them in the 9v flavor so I'm using the Powerex.

Arrived charged and I let it sit for a few weeks; still good but not fully charged. I topped it off and it held the charge well. But when it dropped off in use, it dropped off quickly. Not surprising, that's been my experience with other rechargeables. I'll probably buy another so I always have one charged up. I'm using it in a wireless belt pack for in-ear monitors. My charger is also a Powerex that I used for earlier versions of Powerex 8.4v batteries that finally died after several years of use.

I've owned several sets of Powerex batteries and they have always performed well. This review is specifically for the Powerex D cell 10 Ah variety. I bought these in 2016 and as of 2023, they are still working well. Capacity as reported from my Opus charger is still around 9970 mAh, which I think is great. Although I have them 8 years, I probably only charge them about 4 times a year, so they haven't been cycled too many times. When I bought these, they cost about 60% of what they do now. Given that in the devices I use these in that I would have gone through about 4 sets of regular D cells per year, the breakeven for me came after 2 years, so despite their high cost, they have still saved me quite a bit of money. I was kind of shocked to see the price of them now, so that would be the only negative, but I guess you get what you pay for. They are true D cells with the corresponding higher capacity, not C cells that have been put in a D cell case. If you don't need the kind of capacity these provide, you can save some money buy buying the lower capacity cells, but if you do need the higher capacity, these work very well.