Panasonic BK-3MCCA8BA eneloop AA 2100 Cycle Ni-MH Rechargeable Batteries (8-Pack) - High Performance Pre-Charged Batteries for Cameras, Flashlights, Toys & Electronics - Long Lasting Power Solution

UPDATE 29.12.2021. Meanwhile I took the outer wrapping completely off of 2 Batteries where I detected the wrapping cracked and split as well on the + (positive) pole. These are 2 year old batteries and have roughly 24 cycles through. The Hybrids are 16 year old NiMH and are in a like new shape. Expect the wrapping to peel off from the Eneloops after a year of use. Touching the upper body edge at the + pole and the + pole with multimeter sticks it gets an measuring meaning any metal piece who bridges that small space will short the battery creating a fire hazard. The plastic washer together with the outer wrap prevented that risk to short the battery before when it was in place.Otherwise the completely unwrapped battery looks like is sound to use without the wrapping. There is a washer which will come off when the wrapping is gone but that does not prevent it's correct functioning since I used it like that in an flashlight and charged the battery as well in the condition where I took off the entire wrapping and plastic washer. The plastic washer is an insulator and protects the underneath the + pole lying vent holes to gather debries and dust. As such as the plastic washer prevents objects to touch the + pole and at the same time the edge of the body which is the - pole. I tried to pry up the + pole and the ridge on the body but those are firmly pressed in as it seems. As such the battery is in working condition as well when the entire wrapping is taken off just make sure no water, dust, debries or objects touch at the same time body and + pole since that shorts the battery creating a spart, smeltering and smoke. The outer body of the battery is indeed somewhat sealed and is in working condition like that.Stay away from the Eneloop brand if you mind the outer wrapping falling apart and using the battery bare nacked.UPDATE 28.12.2021. See in attached fotos how I solved the unwrapping und peel off of the outer shell of these Eneloops. I glued it together with an 2 part industrial glue/cement. Looks like it is a temperature resistant glue and I can not even scratch the spills off so attached is it to the outer wrap of the battery. It turns into an cement type layer. That makes it now thicker and I can not fit the battery anymore into the bay of an wireless mouse. In my other appliances like flashlights, radios, etc these still fit. Beside the Eneloops you see the 16 year old Rayovac Hybrids which do not show any problem with unwrapping the outer shell. If they would make these Hybrids still I most likely would just go for them if the price would be reasonable. These Eneloops are about 2 years in use now and the electrical condition is awesome but their physical appearance and outer wrapping is just thrash and could lend to dangerous conditions if I would let it unwrap fully. With this cement glue I believe the problem is solved but surely the customer should not have to fix such expensive items themselves after a couple of years.What I noticed as well the Hybrids outer shell is overlayed by a couple of millimeters which is not the case on the Eneloops. The Eneloops skimped IMHO on the lenght of the outer wrapping being it to short. But that does not explain the cracks and splits of the outer shell on the negative (-) end which is the case on allmost all of my Eneloop batteries even those not in use yet. As if there is a problem with the wrapping material of the Eneloops from the very factory begin on.UPDATE 26.12.2021. I measured the voltage with an Multimeter of these and when full they measure 1.35 Volt and when empty they measure 1.12 Volt. Surprisingly the Hybrid 16 year old Rayovacs mentioned below they clock at 1.21 Volt when they are empty and when full they show 1.3 Volt. But as well the Hybrids cut off power (if you switch off the light when they are empty and then on, the light does not turn on anymore) when passing low to about 1 Volt as do the Eneloops. Both behave similarly cutting off the power (no power delivery anymore) if they are at about 1.12 Volts or lower. I believe it is an deep discharge protection of the battery. Passed that 1.12 volts they dont deliver anymore power and the flashlight does not shine anymore. However the Eneloops dont recoup the Volts to 1.2 V but rather stay at 1.12 V once when empty.Be aware of the outer skin unwrapping of these Eneloop batteries. If the positive (+) unwraps the whole battery can fall apart and be useless since there are some loose parts which are held together only by the outer wrap according to some YouTube videos. This problem has to be addressed by Eneloop since that unwrapping can destroy the entire battery. If this problem persists it may be advised to switch over to another brand, like the amazon brand or EBL and similar. How come the Eneloop have this flaw and my 16 year old Rayovac Hybrid Made in China batteries are in prestine conditions as if they would come right out of the factory.They should make these batteries in stainless steel cylinders which have the + end screwed on and one can change the chemicals from the interior and the parts once the battery reached its life end. Like that the entire outer cylinder would be one piece stainless steel and then the wrap could fall apart without any damage. But like this these batteries do not have an entire sealed outer wall but rather an wrap around as wall and if that comes apart the + end can fall apart in it's separate pieces. A bad design if you ask me.Maybe one should advise against the Eneloop battery brand due to this problem and recommend other brands.Main Review:I have bought allmost exclusively this Eneloop brand and am happy with it since they are technically sound. They hold the charge. If they really last 2100 cycles, that would be awesome since that lends to an 40 year lifespan in about. I went for this brand particularly because they are supposed to hold the charge for 10 years for 70%. So I can store & forget them since I dont use them all at once. These can be stockpiled as well and stored away to have some spares if they hold what they promise. The problem with other brands is you have to use them somewhat continuously in order to prevent deep discharge which damages them. Other brands have to be used lets say at least once every 2 to 3 years so you can not buy a few packages spares and store them just away since they would loose their power and get damaged. Supposedly these Eneloops one can store away for 10 years and use them then once in order to charge them up to store them away for another 10 years if not used. Thats a big advantage since as such you can stockpile these - buy them today and use them for the rest of your life never have to buy again any NiMH rechargeable batteries. That's a huge advantage is that over other brands.I use this brand for now about 2 years continuously and they do what they are supposed to do.They have one problem, thats why it gets a reduced satisfaction and looses 2 stars: the outer shell wrap tends to unwrap over time of use. I guess it is a bad glue they use. As well on the negative (-) end the wrap splits and cracks away and then tries to open up all around where it is glued together wanting to unwrap. I applied to some already a instant glue and that fixes again the outer wrapping. This outer wrapping is clearly an composite material which is metal underneath and on the upper visible part it is a plastic covering. I guess this metal underlayer does not want to stick very well to the cylinder of the battery and thus tends to unwrap. Thats an technical issue and can render the battery itself useless since the battery itself is not inclosed in an sealed cylinder and the internals of the battery can fall apart at the + end if the outer shell unwraps. I considered the outer wrapping only as decorative without any real technical function but some videos demonstrate otherwise. They could as well just have had shipped these without any cover wrap bare naked metal cylinder if the cylinder would be a closed system - but it is not. So thats an negative.I am pretty confident these sort of batteries can be stockpiled without they going bad over a few decades. I bought back in 2005 the first gen low self discharge NiMH batteries from Rayovac called Hybrid which were rated for about 80% of charge after 6 months of storage and most of those are still in use today. They where rated back then for an cycle rate of 500 cycles for 2100 mAh. Most of these are still in use today after 16 years. Of those Rayovac Hybrids I left in an flashlight and forgot about it for about 8 years and they still work and are recognized by the modern Panasonic smart charger BQ-CC17 I use exclusively. So that means these batteries can be stored away without they deep discharge themselves. Those Hybrids where Made in China back then. If these Eneloop do that well as well then you can buy today a few packages of them and store them away so if you need more or the others fail then you have them at hand.I had however some of the AAA Hybrids leak most likely due to never use them and thus deep discharge.Despite the outer shell unwrapping problem I would allways go for these instead of other brands since these are not that much higher priced but advertise at least the double of recharge cycles and have 2 to 3 times longer power storage capability (10 years for Eneloops: this is the intervall one has to use them in order to prevent deep discharge) compared to other brands.However these are empty quicker than the 2100 mAh rated Hybrid Rayovacs mentioned since they have only 1900 mAh (lower capacity). These are noticeable quicker empty due to the lower capacity. So have allways 5 in use where 4 are charged and 1 is in use in my EDC flashlight.Higher capacity means normally way less cycle rates like 2100 cycles for 1900 mAh capacity versus 500 cycles for 2500 mAh capacity. I go for higher cycles rather for higher capacity which you cant be really sure in other brands if they really hold their high capacity claim spacially if they are Made in China.Being Made in Japan, the batch I got till date are technically all sound and work.I use these Eneloops mostly in EDC flashlights and MagLites (with Eneloop D to AA adapters) but as well in mice, control remotes (AAA Eneloop NiMH rechargeables) and radios and in all applications they work wonderfull and last a long time or decent normal time. Obviously these are excellent if used in low drain long time appliances since these have an low self discharge rate of 70% power after 10 years - thats awesome and never seen before.I find these a bit overpriced for our "Tesla battery times" where there is supposed to be a huge ramping up in battery production worldwide. But the price seems have not come down considerably for the consumer yet.I cant see an fabrication date on these so thats a negative as well. Although these should not expire any time soon and should have a shelf life of a few decades, these are most likely not heirlooms which will be working after 100 years. So I would expect to see an fabrication date. However the package at least tells you which generation you got so make sure to get allways the last and greatest generation. To date the 4th gen is the newest generation and that is what I own and this review is about.Yes I recommend these.We were going through batteries in our Kwikset Smart Deadbolt every three months. Since we uses the front door a lot, it was going to cost me a small fortune in AA batteries. They were 4 batteries a pop. So we took a chance on rechargeable batteries. We did our research and found the Panasonic rechargeable batteries were the best. We agreed with the reviewers after they last almost 3 1/2 months So we bought backup batteries from Amazon to use while the other set is recharging. Also Amazon was about 10% cheaper than Walmart or Target.I have been using these for a couple of years now and have been very pleased. I don't know about the economics of these vs alkaline batteries but I have lost hundreds of dollars of equipment due to alkaline battery leakage. From every vendor. That alone justifies the premium for these rechargeables. There are a very few devices that I have found to be sensitive to the 1.3 v of these vs the 1.5v of alkaline batteries. I just have to continue to use alkaline in them and being careful to remove the batteries after use.If you are in the market for batteries look no more. These are the best batteries ever and saying that as a professional using batteries each and everyday. They do have other batteries with higher amps but don't make the mistakes stick with these Eneloop batteries and no others!I’ve been using this brand since I took the dive into rechargeable batteries. Always happy with the capacity and the number of recharges. I have an older charger so it takes a long time to charge but this is not the batteries fault.Now that we have a little one and toys these have been a great to use. They are a little pricey but trust me worth it. I trust this brand the most and highly recommend.I've tried most all of the other brands and Panasonic performs better than the rest. Most other brands just don't hold up over time. Panasonic holds up. I have some that are still working well after 3 to 4 years.We're switching over to reusable batteries wherever we can and these have been great! Only place they aren't ideal is the game controllers - they die so fast. For remotes and other lower use items, they have been great!I have a door lock that uses 4- AAs … they need replacement every 3 months so I opted for these and am hopeful they will last 4-5 yearsShipment was very fast. The original package was broken and batteries were spread in the box. I tested them with a Lacrosse B700 charger and noticed that all 8 batteries were charged between 20 - 50% so I wouldn't expect to be able to use them right out of the box. The capacity found was, for all batteries, under the advertised minimum 1900 mAh (the one showing FULL in picture, was the lowest at 1740 mAh). Having in view their price, I would say they are disappointing and I would rather go in the future with more generic ones like Amazon Basics, which cost less and have a better tested capacity. I don't know if Eneloop batteries accept a nominal charging current above the average 200mA as it isn't specified (if a current above nominal is used to charge, battery's life dramatically decreases). I say this as I saw Eneloop fast chargers, pretending to charge 2 AA batteries in 2 hours which means they are charged at 1000mA. If this would be the nominal charging current, would be a huge advantage but if it isn't, that charger will kill them after several dozens charges. Unless I don't find written they can be charged at a higher current, I would continue to charge them at the general accepted 200mA.Out of package cells measured ~1.3V and required 600-1000 mAh of charge to reach FULL; capacities then tested between 1944 and 2060 mAh, with an average of 1978 mAh (using an Alpha Power/La Crosse BC700).Cell capacities are very consistent and above the advertised 1900 mAh minimum; however, charging before first use is definitely necessary. The amount of initial charge required to reach FULL makes me question the Pre-Charged (& possibly LSD?) claims (measured figures imply an out of package state of charge of between 50% and 70%).Very fast shipping by Amazon.Après 4 à 5 utilisations .seule 2 batteries conservent leur charge pour une durée de plus d' un mois sans aucune utilisation, les autres sont à plats au bout de 2 à trois semaines après une pleine charge .....je regrette cet achat et ce n'est pas normal,je les utilise dans des transmetteurs Cactus VI et j, utilise un chargeur Lacrosse qui charge aussi mes Eneloop Plus qui eux conservent leur charge indéfinement ....très insatisfait de ce produit et malheureusement ,est-il trop tard pour les retourner et changer pour les Enelop Plus ou demander un remboursement?Price: Yes, a bit pricey to buy, but those will be the last ones you ever have to buy, they last for years and years :)Longevity: I am still using that very first set of 8 I bought several years ago and they show no sign of giving up.Note: A good charger is of course a must. (Maha Powerex MH-C9000 / La Crosse Alpha Power Battery Charger)Want to charge and forget? Never have to wonder if the batteries have any charge left after months of not being in use?I used normal NiMH batteries before. The higher the mAH, the less time they retained the charge, 50% loss of charge in one week not uncommon, thus completely useless for most applications (Camera/Game Controller/Mouse).One day my brother told me about these "miracle" Eneloop batteries. Did not really believe him but bought an 8 pack first gen Eneloop to check them out. That was several years ago. Never went back.Took them out of the packaging and without charging put them in my XBOX 360 controller, played a few days, then forgot about them and the XBOX for more than 5 months (new job, etc). Then had time to play again (the same batteries still in the controller, uncharged) lasted for several weeks of intensive controller use. I was very much impressed.Same with any other Eneloop I ever bought. Charge and forget.Longest I ever had one set sit without using them was 9 months after charging them, used them in my digital camera.Already had normal batteries ready as I thought well, those Eneloop are probably done after 9 months. Nope. Ran 350 pics on those, no problem.I have used Eneloop batteries over a number of years, for all kinds of purposes, and have found them reliable, and have not had even one fail. I see no reason why these will be any different.I have run tests of the ability of these batteries to maintain charge over long times of storage, and cannot quibble with the claimed retention percentages. While not totally scientific, these mostly exceed expectation, which may not be important for some uses, but as I use these in camera flashes (as well as elsewhere) they may sit for months, and it is good that their self-discharge rate is as low as it is - certainly much better than cheaper rechargeables.