Tenergy Premium Rechargeable AA Batteries, High Capacity 2500mAh NiMH AA Battery, AA Cell Battery, 12-Pack

excelente producto

Excellent product which I have used before and continue to buy due to it's record of satisfactory service. I have no hesitation in recommending these batteries both due to their performance and their durability.

These are the only batteries that I buy now

These are good batteries. And they’re cost effective when compared to alkalines.

Even though only about 8 of the 52 batteries I purchased since April 2017 still take a charge, these batteries are receiving a five star rating because the reason these batteries no longer take a charge is due to an error on my part.So here is the story. I shopped around for a while in my usual detailed and systematic way and finally decided to purchase these batteries, starting with a 4 pack of AAAs on April 12, 2017. The batteries worked well, so on July 17, 2017, I purchased a pack of 12 AAs. So far, everything was just fine, but I was about to make a mistake that would lead to the eventual destruction of the 16 batteries I had already purchased - and the 36 batteries I was about to order.On December 21, 2017, I ordered a 12 pack of AAAs and a 12 pack of AAs. Unfortunately, I failed to read, and or heed, the instructions printed on the side of every one of the batteries, "Caution: battery can explode or cause burns if overcharged, disassembled or exposed to fire. Do not mix with used or other battery chemistries (alkaline, lithium). Even though I had previously habitually labeled new batteries with their date of purchase, etc., I didn't even think about it when I received the 24 new batteries, and simply put them into service with my existing batteries.By April 2018, I was increasingly disappointed with these batteries because I had already had a few individual battery failures. But I needed more batteries and didn't have time to perform new research to find a new brand, so I placed another order for 12 AAAs on April 26, 2018. The April 2018 order meant that I owned 52 of these batteries, 24 AAs and 28 AAAs. Once again, the new batteries were not labeled before being placed into circulation with the existing 36 batteries.My rechargeable batteries receive heavy use, and previously battery sets purchased at the local grocery store had provided sometimes amazing longevity (up to about 10 years), apparently because I was taking steps to ensure they were recharged regularly (at about 50% discharge). I had hoped to have similar success with the new batteries, but I had never purchased batteries in such large sets. While the differing brand, newness, and external appearance had made it easy to recognize which of my old batteries belonged together, there was no way to tell which of the new batteries had been purchased at what time.By mid-summer, 2018, the new batteries were failing at an alarming rate. Returning to Amazon to read the reviews, I hoped to find out if other customers were having similar problems and to try to figure out if I had missed reviews discussing such a large failure rate. But there were virtually no reports of failures, let alone enough failures to qualify as a rate. Disappointed and frustrated, research began to find a more reliable replacement.Then one day I happened to carefully read the second sentence of the caution warning on each battery, "Do not mix with used or other battery chemistries (alkaline, lithium)." Suddenly, it was clear that although the batteries had not been mixed with other battery chemistries or brands, 3 sets of new batteries had been intermixed with 2 sets of used batteries. Then it became clear why the batteries were failing at such a high rate, the used batteries were apparently damaging the new batteries, and or the new batteries were apparently damaging the used batteries.In an attempt to recover, I tested my remaining batteries and created sets with similar voltages immediately after charging, but the damage had been done. Today, some 20 months after the first order, only about 8 of the original 52 batteries continue to take a charge, and even these continue to fail at an accelerated rate despite the attempt to match them.Therefore, it appears re-purchasers of these - or any other sets of rechargeable batteries - should be diligent about labeling or taking other steps to ensure that new and used batteries are not utilized together to power equipment. Labeling rechargeable batteries with date, order number, tally marks, spray painting, etc. may take a few minutes, but the batteries, and money, you save will be your own.