eneloopPro, AA/Mignon, Rechargeable Battery, Pack of 4, Capacity of 2500 mAh, Ready-to-Use Ni-MH Batteries, 500 Recharge Cycles, Plastic Free Packaging, Pro, Black

I own a Sony U60 MP3 player that is great for recording and I use it often when out as I do not carry a smartphone out sometimes. It has ONE TOUCH record even from power off state. Excellent device despite its storage capacity, with only one flaw.These use a single AAA battery. Clearly these use a DC-DC converter to boost the 1.5V to something else say 5V. Leaves very little wiggle room for voltage drops. But rechargeable naturally have a lower voltage. Normal Eneloops barely lasted two hours in the player and when 'drained' in there still had a bit of use in a walkman before being fully actually drained. Normal Eneloops I have used extensively with very little issue in serious gear like A WM-D6C walkman, but due to the lower operating voltage and faster drain under high current load, it just wouldn't work for very long in this device. It is the FIRST time normal eneloops have failed me, as did other rechargables tested. I ended up using some Energizer ultimate lithiums in the player, getting 5 to 6 days of daily intensive use from a single battery, lasted an entire trip and i came home with capacity to spare. Helps those stay at 1.5V until the end of the discharge curve, so less current (Amps) needed due to the higher voltage. Normal Eneloops therefore prompt a battery change even in a single listening session. Not a flaw of the batteries, but the device by nature needing every millivolt from its 1.5V AAA battery.I reasoned that the Eneloop pros have thinner plates with more surface area and thus will provide more current and likely less voltage drop under load as this is what they are designed for. Would they work where all other rechargables failed?They did. They run the player for roughly 1.5 days of usage of 6 to 8 hours of play. Not as good as the Energizer Lithiums 30 or so hours (higher voltage meant less current draw), but I can use it for a day (or far longer in standby as it draws barely anything), put an Eneloop pro off the smart charger and take the second one to continue use. They perform flawlessly with this device. And it also works that I am not depleting the Eneloop Pros to 100 DoD, so using the Eneloop smart charger will protect the life of these. WARNING ADVICE: I WOULD NOT USE THEM WITHOUT A SMART CHARGER. A DUMB CHARGER WILL DESTROY THESE BATTERIES FAST DUE TO THE THINNER PLATES IF IT OVERCHARGES THEM! Normal Eneloops are far more rugged in this regard.I do not like using primary batteries due to the environment, unless i was going to be on a long off grid trip where the lithiums would make sense.I always bought and for most devices if they work well and the extra capacity is not needed Normal Eneloops as they are far more hardy, thicker plates and can last upwards of a decade of heavy cycling and low self-discharge. But when you need that higher operating voltage under load and ability to handle higher current draw, this battery solved an edge-case of a device that did not like most NiMH rechargables as the extra voltage under load and slightly higher capacity combined to make it a superb battery for this purpose.The interesting sidenote was the battery gauge, designed for alkaline batteries actually was close to accurate. Three bars for an hour or so, two bars for most then 1 bar with still enough juice for say 30 to 45 minutes of play. So its discharge curve in such a device will still give ample warning of requiring a battery change and not a sudden voltage collapse as the energizer lithiums will do in this use-case.In devices that only use a single AAA battery or in devices that need the highest possible voltage from your batteries under load (or if you need more capacity and do not mind 500 cycles over 2000+) use these. I personally would only use these in those power scenarios as I will always usually choose more cycles unless I need something like this.They most certainly got the job done.

Wow. I've used a lot if batteries before finding these and can honestly say these are better than any I've ever used before. Yes. They are expensive, but pay for themselves because they charge so unbelievably FAST. I charge in the battery unit to match and recommend this as a package. I use very high drain led candles and these are so versatile they last for ages. Great power and performance.

The best batteries I have found for my XBox controller, they keep charge for ages

Overall I am "ok" with these batteries.They are of regular size, sometimes rechargeable batteries can be slightly off typical sizes and then cause fitting issues. But these have fitted into all the devices I have used. Even the sleeved type devices that have a tight fit.Be aware that all rechargeable AA batteries are rated at 1.2v and you do get a rare device that will not work at that voltage, expecting the more typical 1.5v of regular alkaline types.We have had one device that works but will show low charge, it isn't a low charge it is just the device is picking up on the lower than expected voltage. But it does work fine.I have got two decent battery chargers.Please see the photos I have included.Whilst they have claimed a minimum of 2500mAh for these batteries mine have ranged from 2445mAh to 2610mAh. Two of the four being under the minimum of 2500mAh.That was after two full cycles of discharge and charge, tested on two chargers.When these batteries arrive they are advertised as being pre-charged and ready for use, but they are certainly not fully charged.The resistance of these batteries is measured in milliohms, typically 20 to 80 milliohms being considered very good. If they are over 500 milliohms then they will not be good for high powered devices, like digital cameras. The highest I have seen , shown in a photo, is 116 milliohms for one and 48 milliohms for the other. So they seem decent enough.So far their life, capacity and capability is ok. Apart from two of the four that are below the minimum noted of 2500mAh. I had one of those in one hand controller of my VR headset and then the highest in another. The one with the lowest capacity, as expected, ran out first. It does make a difference.I would have expected them all to be close to or over 2600mAh, appreciating there will be degradation over time. So in that respect, as it is an advertised feature, then that is part of why I have reduced the rating by one star.The other reason that has contributed to that four star rating is the price. They are comparatively expensive and so the expectations of them meeting their advertised specifications is reasonable.As noted, overall I am "ok" about these batteries. I'll continue to use them and see, over time, how they last.I will edit this post as time passes if there is anything of concern regarding their use.Being just "ok" will probably mean I will look at other options for more batteries of this type.I hope this review has been helpful.

The batteries are the best rechargeable ones I have ever bought, they are quick to charge and are maintain a good level of energy.

Great long lasting

A good set of rechargeable batteries at a good price that arrived already charged.

Product was used today, in excellent condition, works well..Thanks Panasonic.