Amazon Basics Rechargeable D Cell Batteries - 4 Pack NiMH 10000mAh High Capacity - 1000 Charge Cycles - Pre-Charged for Immediate Use - Ideal for Flashlights, Toys, Radios & Emergency Power Backup

Update on Amazon Basics Size D batteries 3-11-23If yu’al have been reading my reviews of these, I guess it won’t come to any surprise that when Amazon lowered the price again, I bought 2 Four Packs…..Let me call these battery numbers 13 thru 20….These were delivered on 3/1/23…these all had a date code of 09/2022…I started my normal discharge/charge cycle on my IQ338XL charger..Now the 1st discharge on these are only telling you what the batteries have in them after sitting on a shelf somewhere until delivery….(the 1st discharge isn’t all that meaningful except to make sure the batteries aren’t completely dead)….And for the 1st time, number 13 thru 16 failed the testing….I did the same cycling 1 more time…and they didn’t recover….These 4 came in about all the same 7000 mAh discharge and around 9000 mAh charge for both cycles…The charger measured the internal resistance from 15 to 30 m ohms….I then started to do the same with the next set of batteries…which I will call numbers 17 thru 20….and these all came in with a discharge of 7400 to 7800 mAh and a charge of 11000 mAh to 11600 mAh…these were all good. I sent back the other 4 and Amazon sent out replacement batteries….Which I now call 13 thru 16…again….these had date codes 04/2022….which are even older than the others…..2 of these checked out OK….I proceeded to do another discharge/charge cycle on the 2 that didn’t measure up to their specifications….They did come alive…So, the new 13-16 batteries measured in at 6800-7400 mAh discharge…and 11000-12000 mAh charge…Now remember that the original discharge numbers are what the batteries came with after sitting on the shelf for some time….Some NiMH batteries, it takes a number of cycles to “wake” them up….I did 2 cycles on the first set of 13-16 and that did nothing….where the 2nd set of number 13-16, 2 of 4 came right up to specification and 2 did not…another cycle, those 2 came right up to specifications…The next discharge numbers on fully charged batteries are expecting around 10000 mAh…That is just the way they work.This was the first time that I had purchased some bad batteries. I always thought bad batteries were just a scare tactic.I will continue to report back on these batteries. They all seem to be very good….I have them in a Maglite 3 Cell flashlight with a very cheap LED replacement light installed. There are 4 installed in a Eton/Grundip Satellit 750 radio, 4 installed in a HF 1250 Lumen LED Lantern…and another 6 installed in an older 800 Lumen LED Lantern…and 3 sitting in a drawer…(On the Shelf)Testing these over the years I have come to a 2 year recharge cycle on them unless there is a lot of use, which there hasn’t been….Time will tell. More to follow….that is if I’m still around to report back…Update on 11-1-22. Well the price is finally coming down. Well done. I will update this with more findings on the size C in a week or 2. I just recharged them after 9 months of use in my 1970's Sony radio. I still see nothing wrong with these batteries. They still charge up to the 5000 mAh value and beyond. More to come. The Size D's are finally coming down in price also. In fact they are almost back to their pre-covid days. But, I got a deal on the last Prime Day....so I purchased 2 more sets of the Size D. 1 set for my ham Satelitte 750 receiver and a HF 1250 LED lantern. More to come on this too.Update on 8-9-22. Amazon won't let me relay anything about my size C Amazon Basics NiMH rechargeable batteries that were purchased on 6-19-20 for $12.49 for a 4 pack. Today Amazon finally has some of them in stock....for $20.99 for a 4 pack. All I can say is WOW. That is quit a price increase in little more than 2 years.....I can hardly wait to see the size D prices, if and when they get stock on them. BTW, this is the worse inflationary story of our time....this comes to 68% increase in 2 years....OUTRAGEOUS price increase. Amazon will only let me review my size D purchase on the same date, which I can not understand.Update on 7/27/21 for tests on 6/11/21 (Or about 1 year after original review) Batteries 1-3 have been insalled in a 3 cell Maglite for the year. This flashlight has a cheapie LED lamp. It is of the original Mag light design, not the newer ones with LED lamps. There was little use on these batteries. The light was tested for 5-10 seconds each month just as a battery check. These were discharged to check remaining charge. The discharge ranged from 9052mAh to 9724mAh. Which comes out to 90.54% to 92.74% remaining charge from their rated 10,000mAh. Once again, these batteries are testing out very nicely. They charged up to between 10830mAh to 11660mAh. The internal resistance measured out between 15-19 milli ohms. These 3 batteries also show low self discharge characteristics.Update on 7/27/21 for test on 3/21/21. I took Battery #4, which has been sitting in a drawer for 9 months. So this is a 9 month shelf life check. I discharged & charged the battery. The discharge after 9 months was 9230mAh. That is down ~7.9% from the rated 10,000mAh. So far this is fantastic and does show that at least 1 of the 4 batteries has low self discharge characteristics. (This battery measured 15 milli ohm of internal resistance)This review mirrors my review of Amazon Basics Size C NiMH batteries.I received these on June 21, 2020. I let them sit for an hour to acclimate them to my environment. Reading the instructions/paper work that came with these, you are to charge the batteries at least once every 3-6 months. (This does not give me any warm fuzzies about Low Self-Discharge characteristics of the batteries)Now this seems to be in opposition to the web page which states: Long battery life, extremely gradual self-discharge; maintains 80% capacity for 24 months. (This does give me warm fuzzies about Low Self-Discharge characteristics of the batteries)But what is it….6 months or 2 years. Time will tell. Hopefully I will be alive to report on this and Amazon accepts my added review, which they do not accept very many of my reviews for some reason.Now for early testing: I used my IQ338XL charger for the tests. Set it to charge test, which first discharges the batteries, stores the discharge current/time/internal resistance, then it charges the batteries, stores the charge current/voltage/time/internal resistance…..and when all batteries are finished, the charger flashes the display. This charger is preset at 500 ma discharge and can not be changed. So it will take a very long time to completely discharge these size D 10000mAhr batteries, especially with a full charge. On charge, this charger current is selectable…500, 750, 1000, and one level higher, which I can not recall. I set the charge current to 1000mA.Upon completion of the testing all of the batteries were between 1.45 and 1.46 volts, 10830mAhr to 11660mA and 15-22 mOhms internal resistance. These batteries came with a charge of 9052mAhr to 9724mAhr, which is 90.52% to 97.24% of the rated capacity. This is fantastic.To completely discharge the battery with 11660mAhr charge capacity at 500mA load current would take around 23 hours…..So, be prepared for the time it takes. And then it has to charge them…and at 1000mA of charge current it will take almost 12-13 hours. So basically a day and a half to do 1 cycle of discharge/charge.These batteries were dated December 2019. Now for the warm fuzzies of Low Self-Discharge…..It is now the 3nd week of June 2020….so lets just call it 6 month shelf life and they came with 90 to 97% charge…WOW...how can this be true??? I have never had this much charge left in any battery after 6 months…but the again….how often does Amazon charge them while on the shelf…no one really knows.Well, time will tell.