Tenergy 8 pcs of Premium D Size 10,000mAh High Capacity High Rate NiMH Rechargeable Batteries - UL Certified

I own 8 of these great rechargable batteries. They work very well and keep the charge a long time used in a baby mobile. The issue is, that the baby mobile draws a very low current and the batteries get exhaustive discharged and appear dead to the charger. After refreshing, the dead battery seems to be fine. 4 stars because of the high price. How to refresh a "dead" battery: I read on a discussion board, you place the "dead" and an equal sized battery in your charger. Take a paperclip and connect the plus(+)-poles of these two batteries. Wait 15 minutes and remove the paperclip. The "dead" battery keeps charging. Update 06/13/2016: The price is now reasonable. Changing to five stars. The best is, I have bought these batteries 4 years ago and we used them constantly for a crib white noise toy. Now after four years 3 of the eight show signs of fatigue and will not hold the charge much longer. Well worth the price. Go for it!

I have used the 8 pcs of Premium Tenergy D Size 10,000mAh High Capacity High Rate NiMH Rechargeable Batteries for over a year, and have been pleased. I have seen this brand used on TV and movie sets, and already know the quality - this is a best-in-class item. Around the house I use them for the lovely, but energy hog "Luminara" flameless candles - which are also best-in-class ( and used at theme parts, movies, TV and Broadway). After a year++ of use, I can assure you that that the product is well worth your consideration. To be fair, they are costly, but in this case, you DO get what you pay for - excellent results! You will need to get a premium charger, but will be glad you made the investment. During the holiday season, I needed/wanted to include D battery packs for several gifts. Suggesting re-chargables can be a tough sell for some. They wanted the regular battery set up. Ugh! I easily spent around $8.50 per 4-pack, and freaked-out when I needed one more and bought a pack of regular battries at a quick shop store (think "numbers" LOL) and paid close to $12.00. Just do the math here. Bottom line: * The product is heavy, but are REAL D cell/s unlilke other brands which encase AA's to create the D shape .. * It is a brand studio's use, it is a professional item. * Will save you money over a short period of time. * You can use them over-and-over. * Outstanding quality, and a trusted brand. Get the good ones here, you will NOT be sorry. Over time, it can be kind of fun to quantify your savings, too. I can ASSURE you that studio's do!

[Capacity:] Tenergy seems to have world wide the highest rated capacities for rechargeable NI-MH batteries. Looks like Tenergy has almost maxed out of whats technically possible. No other maker has these capacity range, hats off !! Even the best Japanese makers have max roughly only 60% capacity (5700 mah), again respect for this !! It's awesome how much capacity this rechargeable batteries have. [Weight:] Lets face it, batteries are heavy. Capacity limits and weight are probably their worst obstacles. Fortunately the extended capacity plays as advantage as you might come by with one battery pack where you used two or more in the past. This comes in VERY handy when either every gram counts or stamina is everything. [Charging:] We all know that increased capacity not only gives you better mileage but also requires fewer (but long) charging cycles. Generally speaking high capacity is a good thing but long charging times might be a turn off when you are in hurry. In addition quick charging or charging to often (to early) might decrease life cycle of the battery (read: damage it). So it makes sense that you also invest in an "intelligent" charger, that checks the battery status, de-charges it controlled and recharges it gently. This way your investment is protected. [Usage:] So far I have used those batteries and haven't realized any significant drop of capacity. Its to early to tell the long term quality of the product, however so far everything is indicating a good quality product. I will update this section in regular intervals to indicate any capacity changes. ---[Summary and target user:]--- I am conservative. For the technology and capacity alone I would easily give 5 or even 6 Stars. I understand that 10.000mah is a capacity that is almost unheard off and more likely bikes or even small car batteries have it. For the average user even 50$ + charger cost is a deep price to pay, so its not a deal for occasional uses. HOWEVER, for power sucking heavy usage this is a steal, especially if you MUST HAVE the extended stamina. 5 Stars for heavy users 4 Stars for average users ((Reason is initial cost) Enjoy the ride !!

EVERYONE NEEDS TO READ THIS (SOLUTION TO ERRORS AND LONGEVITY) who has troubles believing these batteries are bad (won’t change showing an error or null). I have many “SMART or INTELLIGENT” chargers (controlled by advanced auto sensing circuits) and IF the battery is drained below a certain point or depleted, sometimes these batteries show an error or simply are not recognized because the intelligence can’t detect a fully dead battery or below a certain voltage. IF YOU USE A CHARGER WITHOUT THE FULL AUTO SENSING “intelligent” CIRCUITRY, IT WILL CHARGE. I have placed these “supposedly malfunctioning” batteries in a MORE MANUAL CHARGER THAT IS NOT SO SMART (just auto-off) for 10–15 minutes (enough to infuse a certain charge or polarity, then place them back into you smart charger… bingo. THEY ARE RECOGNIZED & CHARGES 100% or the time. Or just leave them in there until charged. I have used this solution for many years and it works 100% of the time on battery that seem to have errors / unrecognized with intelligent chargers, many hundreds of times. These older more manual chargers just begin charging when you place a battery in them, it doesn’t look for status, battery voltage or battery type at all, it just sends a charge, then shuts off when it reaches a certain voltage. Buy one of the “dumbest” or “least intelligent” UNIVERSAL chargers you can find and THIS WILL WORK WITH ALL batteries you thought were defective. I have 3 old model Rayovac PS3 Universal chargers and THESE WILL CHARGE ANY BATTERY THAT AN INTELLIGENT CHARGER HAS AN ISSUE RECOGNIZING (or will get it started). I have at least 7 newer smart chargers (especially those with bar meter displays) and THEY ALL have various issues one time or another with some depleted batteries, but not these older chargers. ISSUE OF NOT LASTING LONG: Also I have noticed that all my intelligent chargers tend not to fully charge a battery, as these less intelligent chargers will. Batteries charged in a modern intelligent charger just never seem to last as long. But when charged in a more manual non-sensing charger (ie. no bar / voltage display) just with auto off, they last so much longer because they are charged more fully. I have experienced this for many years. In fact, I can take ANY battery that is “fully charged” in a newer intelligent charger with a bar meter that claims to be fully charged, place it in the more manual universal charger; and it will continue charging for a few more hours (Cs or Ds), indicating that it isn’t really fully charged to capacity. This is also the case for AA’s as well, but obviously shorter extra charging times. If I recharge those batteries BEFORE getting too depleted, they are recognized, w/o the error indicator. You don’t have to believe me, but you will be a believer if you get your hands on an older or simple auto-off universal charger, it will be an awakening and you will be a believer then. (and don’t argue the merits of intelligent charging over simple chargers - that’s not the point here). THIS IS TO GET YOU PAST THE ERROR STAGE AND CONTINUE USING BATTERIES YOU THOUGHT WERE DEFECTIVE - AND RESURRECTS THE MONEY YOU THOUGHT YOU WASTED ON DEFECTS & ERRORS.

TENERGY IS NOT GOOD.BRAND - D-batteries ($80 dollars for 12 batteries (i.e., not cheap) - Bought these batteries in January 2017 - I charge all my batteries every 3 months to top them off (yes I know, I little crazy) with a soft quality charger (i.e., one that does not quick charge / not good for the batteries), stored them in my house (i.e., not in cold temperatures) - I never even used these batteries as I bought them just in case I needed the for lanterns, etc. THREE OF THE 12 BATTERIES FAILED, STOPPED TAKING A CHARGE AND BECAME HIGH PRICED PAPERWEIGHTS. AFTER ONE YEAR AND SEVERAL MONTHS. Called customer service and TOLD ME THEY WERE ONLY ON WARRANTY FOR 90 DAYS (THAT'S RIGHT, 90 DAYS - BE WARNED). I have well over a hundred other batteries of different brands (e.g., Odec, Panasonic, Duracell, Eneloop, Energizer, AccuPower AccuLoop), several of which are 15 years old. I then took the time to compare how Tenergy matched up in the D, C and AA sizes (several Tenergy AA batteries that were 1.5 years old already failed, and I simply threw those out because they weren't as costly. In every instance, the Tenergy batteries just didn't last as long, even when benchmarked against my old ones. CALLED CUSTOMER SERVICE, AND WHILE THEY WERE VERY NICE, THEY TOLD ME THAT IT WAS NORMAL THAT RECHARGEABLE BATTERIES SIMPLY FAIL (EVEN WITHIN A SHORT PERIOD OF TIME), AND THAT THESE PREMIUM EXPENSIVE BATTERIES WERE OUT OF WARRANTY AFTER 90 DAYS (WOW), AND I WAS SIMPLY OUT OF LUCK - NO ACKNOWLEDGEMENT THAT IT COULD HAVE BEEN BAD BATTERIES/BATCH OR THAT THEIR BATTERIES MAY NOT BE ALL THAT GREAT TO BEGIN WITH. THIS IS MY SECOND REVIEW I EVER WROTE, SO I'M PRETTY EASY TO PLEASE (HUNDREDS OF PURCHASES).

Wow, it's expensive for just 8 batteries!!! It takes forever to charge! I don't know why I even give it 5 stars!? I'll tell you why...it last forever! Well, not forever...but very long. With one charge the batteries last quite awhile. My son's toys uses 4D cells a lot and with the regular brand batteries his toys usually give within a week or two. But when using these...they last over a month! So in the long run, I'm saving a lot of batteries/money. The only draw back is it takes quite a long time to charge or you can say 8-15 hours to fully charge (on a totally discharged battery). Which in a way is OK, not good, but OK, it's not good to rapidly charges your batteries anyway, it will drain the life of it. It will be less useful in the long run. And one other thing make sure you by a decent charger that doesn't over charge your batteries. I have the Ansmann 5207123 Energy 16 Charger which is also one expensive s ucker! But with the Ansmann I really don't have to worry about the batteries being overcharged or it's going to exploded in my face. The Ansmann is one of the safest, easiest, and most comfortable charger I have used. Especially for these highends battery! So protect your investment wisely! If you use batteries a lot...using the combination I have...in the long run you'll get your money back and safe some! Great batteries! But dang it....so dang expensive!! But did I say you'll save in the long run? :)

I have had these batteries for only a couple of weeks so far. When I got them I put one set of 4 batteries in the tenergy advanced universal charger that I have and put them on the discharge cycle and they fully discharged and then recharged. The other set of 4 I put in my 4 d cell maglite and discharged them by leaving the light on untill they were dead. They lasted for a few hours considering they were not supposed to be charged in the first place. After putting in a fresh pair of fully charged set of these batteries into my 4 d cell maglite they ran for 18 hours before dying. The tenergy charger that I have will only charge d size batteries to 9700 mah not 10000 mah like the batteries are rated at acourding to tenergy, but if you take them out for a few hours and then put them back in they will charge for about another hour and you should be at full capacity. So the 18 hour run time was not at the full 10000 mah like the battery is capable of but still is way better than buying disposable d cell batteries. ps: I had one battery that I fully discharged and then tried recharging and the charger said it was bad. I took it out of the charger for a few hours and then tried charging it again and it took a charge. I don't know why that is but its working now.

Of course the seller of any product nowadays wants you to give a review on what experience you had with it, and whether you classify it as good or not. As far as rechargeable batteries are concerned, the only way to truly classify their performance is by the long run and is difficult to do so when they are brand new. Why did I chose these batteries ?? Because of T-Energy's reputation and years of their dedication to making rechargeable batteries. I had already bought six T-Energy Premium AA batteries to power up a game trail camera designed to take pictures, time lapse, and video. Those have performed flawlessly when left out there in the woods, miles away in all sorts of weather, to do their job. T-Energy had already advertised a while ago that they were going to come out with a version of their batteries known as Premium. I decided to give them a try with those AA's even though they were not classified as low-self discharge. I am almost 100% sure these 'D' version batteries would do the same. They were bought due to an unexpected Easter trip camping this past April 2019, where I needed eight 'D' sized to power up a number of battery operated lanterns. They did their job superbly well on this three night camping trip. Although they operated for a small number of hours each night while camping, they have not - to this date and as of this writing, needed a recharge. They were not given a full discharge or cycle because there was no time. They were given a simple recharge when they arrived. Mysteriously their terminal voltage only went up to 1.40 which was quite odd. I believe this was due to the fact that they still needed this rejuvenation cycle where they have to be fully discharged, before being recharged all over again. And it appears that this needs to be repeated a number of times to get over what I classify as the 'break-in' phase. Again - too early to tell as far as their performance is concerned, but with T-Energy's reputation and the fact that these are classified as 'Elite' in performance, I feel confident they will do a great job in the days and years to come. Will give any additional updates as time goes by in case their performance goes awry.

I use them in an electronic cat door, and they outlast regular batteries before needing re-charge. This is great because changing the batteries in this door is a pain. The product is exactly as described. I expect they will easily pay for themselves plus reducing waste/garbage.

last longer than the rest will order more

Great