I recently had a AA Eneloop stop holding an adequate charge. Trying to make sense of the codes on it, I realized it was at least ten years old! That's remarkable longevity. These batteries are expensive up front to buy, but if you do the math on how long they last compared to a single-use alkaline battery, it's almost comical how much you will save.

The secret I've discovered is to buy a handful more than you need. Because they can hold a charge for a long time in storage, I have a buffer of about a half-dozen AAs ready to go. When I need to replace batteries in something, I grab from that pool, and immediately pop the depleted batteries on the charger before putting them back in the pool of charged batteries.

I do use a third-party Lacrosse "smart" charger, which supposedly helps with longevity. If nothing else, it shows me how much of a charge each battery took, which makes it easy to see if the batteries are still holding good capacity. I'm not convinced it's essential, but as a geek writing a lengthy review of batteries, I sure do appreciate it. O:-)

At this point, except for the cheap alkaline ones that came in a new remote that I'm using rather than throwing in the trash, every AA and AAA battery in my house is an Eneloop. I don't see that changing.

I found the Eneloop around 2008 and used them constantly in my photography business. They lasted a long time, gave power at about the same level as disposable batteries, and with a good charger would be ready to go in a couple hours. I used them hard for about 8 years. They don't last as long now but they still take and hold a charge and having a bunch of them around is good for flashlight and remote control emergencies.
I bought this set to operate a battery operated dental waterpik. The waterpik was eating my battery power and my old Eneloop batteries would only pump high pressure water for about 3 days. The new ones go about 5 or 6 days before a 2 hour recharge. Duracell AA batteries last 3 days!!!

These are good NiMh cells, and I don't really have any complaints. However, the cells don't really hold "70%" of it's charge for long. The cells were lightly used, charged fully, and probably around 25%-50% charge after less than a year. Keep in mind they were used and I didn't do any scientific testing, just what I noticed. The cells do hold a good enough charge that I don't worry about storing them though. I've used these cells in everything from flashlights sitting in a hot car to solar lights sitting in 115°F+ with no issues, and they're still going strong. These cells aren't the best out there especially for the price. I prefer a certain Swedish furniture store's batteries more than these. The biggest thing for NiMh is just make sure the cell is made in Japan.

I used to buy Duracell batteries exclusively until we kept having problems with them leaking, so we decided to look into rechargeable batteries. After a lot of research, we settled on these and they work amazingly well. So many things use batteries, so we go through a lot of these. I've bought at least 3 sets now so we have enough for all the various things that need them and have extras to keep charged. They last for a good amount of time and charge quickly for the next use.

I have lots of Eneloop batteries, for headphones, portable fans, etc. I select various products specifically if they are able to be used with AA or AAA batteries. I rotate my batteries so that I'm always using batteries that were charged a month or 5 months previously.

These batteries do exactly what I expect them to do. HOWEVER, you need to treat them correctly. I have a smart-charger, a 10-year old La Crosse unit that allows me to dis-charge batteries, refresh, whatever. I always charge my batteries at 200 MaH speed. You do not want to quick-charge a battery. If you do not get a "fancy" charger, then your batteries will not last you as long as my batteries do. You are also guaranteed not to get as FULL of a charge on each battery. In other words a cheapie-charger usually charges batteries in a PAIR. It may bring 1 battery up to 2200 of MaH use, and the other one might be 1800 or less.

Sometimes I am using a set of batteries in a scale or fan, and 1 battery will be more drained than the others. If you CHARGE 2 batteries in an inexpensive charger, it will stop charging when one battery is full, in a manner of speaking. This means that 1 battery will usually not get as full of a charge as possible. It is very important that each battery can be charged separately.

Batteries do get "memories" in them. Every time I charge a battery, I set my charger to DIScharge, then it charges the battery after it drains it down to almost zero. Sometimes after a year or more of use, the AA batteries will only hold a charge of 1600 or so, and I turn my unit to Discharge-Refresh. It runs for about 24 hours, and then the battery has higher capacity again (over 2000 and I'm happy). I have had Eneloops for 10 years and I've never thrown any in the trash. I'm sure I've lost some though.

Even if you do get a FANCY charger (they cost $40 or $55 bucks), you still will need to have a cheapie charger, because sometimes my Eneloops get down to Absolute Zero, and my fancy charger cannot recognize any battery at all. I have to use my cheapie-charger to get at least a small charge into a dead battery -- then my LaCrosse unit will charge, or refresh my battery again.

Long story short, if you don't have patience and interest in prolonging your Eneloop batteries, they will not last for a lot of years, like mine do. I am strongly against wasting money, and also adding bad things to the landfill. If you are not serious about your batteries, BUY these, and then buy more in 2 or 4 years, when they do not hold as much of a charge as they did when they were new.