Powerex Low Self-Discharge Precharged AA Rechargeable NiMH Batteries (MHRAAP4)

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.

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 still have AA 2700 and 2800 mah batteries that are over 10 years old that still work in low discharge. Yes they are pricey but much better value than the cheaper batteries that you can find here. I measured the capacity using the MH-C9000Pro charger/analyzer/conditioner and they all came up to over 1000mah after 3 charge and discharge cycles. I've tested a few different brands of AA and AAA(energizer, tenergy, etc) and they all come up short in the tests. I've not tested capacity of C or D batteries yet because my unit is unable to test them natively but I did buy some adapters that will connect to this unit and able to charge the 10,000mah D batteries. I use some "fake" C size batteries that really only have about 1500mah of capacity for an inflatable bed that I use a few times a year. The batteries are just enough to inflate so it's not like I need HI capacity C batteries for anything. I am curious though, I would love to put to the test the real C and D batteries, but I rarely use them, so the cost is too expensive for me to buy these to use twice a year. So if any of you would like to send me 1 or more C or D batteries to do an engineering analysis on, I would be more than happy to discover which C/D batteries have the highest capacity. I can also test 6 months later, how much capacity is left. I will be posting the actual picture showing total capacity for each battery after the cycle. I charge at .25C and discharge at .5C. Meaning it takes 4 hours to charge and 2 hours to discharge. I used this device to measure capacity and break the batteries in. https://www.amazon.com/Powerex-MH-C9000PRO-Professional-Charger-Analyzer/dp/B08DJDQ4Y8/ref=sr_1_2?dchild=1&keywords=powerex+charger&qid=1601666623&refinements=p_89%3APowerex&rnid=2528832011&sr=8-2

WINNER POWEREX - I Bought Panasonic, EBL and Amazon Basics Which Were Terrible I fully charged the Panasonic and Amazon Basics rechargable batteries and lightly used them and they both were going bad in less than 2 days. I was ready to give untill I saw the Powerex AAA rechargable batteries and decided to buy them. I charged them up and and they are still going strong after a week. I finally found a company that makes good quality batteres. Conclusion: Do not waste your money and time and just buy the Powerex Precharged Rechargeable NiMH Batteries which are the best.

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.

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.

I have read virtually all the one stars because I was amazed anyone could not rate PowerEx Batteries at 5 Stars. All the negative reviews have one thing in common - they are not using the MaHa Charger that these batteries REQUIRE. I've used PowerEx Batteries at home but mainly in all my Pro Audio Equipment weekly for over 20 years. Mainly 9Vs and AAs but a few AAAs. That's wireless mics, wireless guitars, PMS (in ear monitors) and multiple pedals and devices - almost all of the MFG's of Pro Audio Equipment suggest that "rechargeable's are not sufficient for use" yet these work without issue and they are the only ones that I've found that do. Batteries last normally through one 2 hour performance followed by a 2 hour rehearsal (4 hours total) and probably would go longer, but I always use fresh ones for performances and charge after rehearsals. Because of the number of batteries I keep on hand, each one is normally charged about once per week and last 4 to 5 years at this rate of usage. In the MaHa charger they charge in 2 hours. In their final year of usage it takes 3 to 4 hours to charge. I write the date on each battery when I remove them from the packaging in order to know when they are nearing the end of their life - which means they no longer last through the rehearsal. There is no other rechargeable battery that I will use or recommend - but the key to these batteries is using the right MaHa Charger that is made for these batteries. Don't blame the batteries if you are not going to use the right charger - These are worth every penny and have saved me $1000's of dollars through the years.

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.