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).

This is a must have, for the MAG LITE ( D cell ), along with the LED LAMP converstion, the batteries last a good bit, before recharging

Good items

I have 24 of these (white) 10,000 mAh Tenergy batteries and not one of them has failed in 4 years. Of course I don't let them run completely down and occasionally I do a complete discharge-recharge. I think the majority of failures are caused by not following these 2 procedures. And to those who say they don't last as long as a regular "D" cell. Depending on the application this can very well be true because a standard alkaline has 1.6 volts when new and these Tenergy's have 1.3 volts when charged. So, with slow drain applications the regular alkalines will last longer. The whole point of these Tenergy rechargeables is NOT to last longer but to save money on replacements. Also, after a couple of recharging cycles these Tenergy's will last longer and be very comparable to the alkalines. Many don't want to take the time to understand the recharging principles and the differences between voltages of alkalines and NiMH batteries. That's cool, but I don't consider it very prudent to downgrade a product for lack of proper research and education on how they function. If this whole charger-recharging process is too complicated or too much fuss, then yes I suggest you stick with the Alkalines. Or if you simply don't use that many "D" cells. There may be bad samples out there, but I haven't obtained any yet. I usually charge them about every week so the original 8 have well over 200 charges on them, so when you consider buying 200 batteries vs. one of these, the price difference is huge. Even at a buck for the Alkalines, that's $200 vs. $8 for the Tenergy's. But yes, it takes some proper usage and charging methods to keep them is top shape to last this long. But as you can see its well worth the effort. Also, all of these batteries were charged using the Tenergy T-9688 Super Universal LCD Battery Charger with USB Port. After reading some of the reviews of people using MUCH more expensive smart chargers I sometimes think they may be too smart for these particular Tenergys. A friend of mine had one that showed dead on his Maha charger but I took it, reconditioned on the Tenergy charger mentioned above and the battery is fine. I figure if I'm using Tenergy batteries might as well try the Tenergy charger first, and 4 years later it has proven the best route. kd