USB D Lithium ion Rechargeable Battery, High Capacity 1.5V 12000mWh Rechargeable D Battery, 4 H Fast Charge, 1200 Cycle with Type C Port Cable, Constant Output,2-Pack

I have looked for a product like this for YEARS now and I am glad it finally exists. I ordered this and waited weeks for it to arrive. I am only using one of the batteries but I have an "every day carry" flashlight that uses a single one of these batteries and this works perfectly. My original battery was worn out and my replacement batteries need a physical charger (can't be charged on battery) but this is the best of both worlds. Way more capacity than the original battery and USB-C charging!Time will tell how they last and I will report back if they fail but right now I am super happy!

I have been looking for a suitable replacement for the D Cell batteries that my equipment needs. I've tried various brands of the large capacity NiMh batteries and none worked properly. Immediately upon installing freshly charged NiMh batteries, my device would show the batteries where at half capacity (as detected by the equipment). After 45 minutes to an hour it would start to tell me it was time to turn off due to battery depletion. So I decided to give the 1.5 Volt D Cell Lithium rechargeables a try. I was a bit dubious but what the heck. I ordered 2 sets of the D1 batteries (a total of 4 batteries, my device requires 3). I gave them an initial charge and plopped them in. Well, much to my surprise, after 5 hours the device was still showing a full charge. I had never gotten this even with brand new high quality Alkalines. I turned off the equipment and waited a couple of minutes to see if the device would go through a cold start because it draws a bit more current from a turned off condition. No problem, it started right up showing a full charge. At this point I ordered a couple more sets so I would have a back up. The only thing left to see is how fast these will self discharge. Since the battery is always in an active state it has to draw at least a small amount of current, so I don't expect them to have the same shelf life of a regular style battery. Anyway, I just wanted to say that I am very happy with these batteries. Hopefully I with get many cycles out of them.

They are working fine for now but I’ll see how long they last they do have a very small capacity listed.

I recently got a new lightweight pump, and I was a bit shocked to find that it required d cell batteries. D cells are increasingly hard to source, and they are becoming a bit expensive. So I was pretty stoked to find these USB rechargeable d cell batteries, and at what I would consider a very reasonable price... about twice the price of a single set of alkaline details. These batteries have a tad more voltage at full charge then a fresh set of d cells, and when they run out they take about 40 minutes to charge. Already, in just a few weeks, I have recharged them about four times and that has saved me quite a lot of money.

Review Update July 15, 2023I give up. alkaline batteries will last a year. These only last about two months. I'm tired of the slow dimming of the motion detection light and having to charge these. I'm tossing them into the circular file and switching back to aliakline batteries for this application.Review Update April 14, 2023These batteries are lasting about two months where alkaline batteries last over a year. This is very poor peformance, especially considering how much I paid for them.Review Update Nov 21, 2022As I said in my main review I installed these 4 batteries in an overhead motion detection light in our garage. Alkaline batteries tend to last about a year in that light. These lasted about 3 months before the light wouldn't turn on. So they seem to have far less capacity than the Alkaline batteries. I won't be buying this type of battery again.At this point I can't recommend these batteries.Initial Review Aug 31, 2022Why did I buy 4 of these batteries?We use virtually only rechargeable batteries in our house. We have over 200 AA and AAA eneloop type batteries in use for multiple camera flash units (Speedlights} several toys, audio equipment, etc. They have served us well. In over 7 years of use I've only had two batteries fail. Every electronic device that takes AA or AAA batteries can be powered by the batteries we have, all but one device that is.One device is an overhead battery powered motion detecting 8 inch light. It takes four C cell batteries and will not work with the lower voltage (1.2V-1.3V) eneloop type batteries. The user manual for that light specifically states that 1.5V batteries must be used. And it's true. The light simply won't function at all with eneloop batteries. So I've been powering this light (actually we have three of this type of ceiling light) with Energizer batteries. They aren't too expensive and the lights are efficient so the batteries last a minimum of 6 months. Still I hate throwing away or recycling alkaline batteries. We've had such good performance from eneloop type batteries that I was willing to take a chance and ordered these.The test...I fully charged all four of these C2 batteries before installing them in one of our ceiling lights. The good news is the light does work with these 1.5V batteries. However there is a noticeable delay between the time we cause a motion and the light comes on. It's not a long delay, more like 2 seconds. But we count on these motion detection lights to come on as we step into the garage. Until one of the three lights comes on it is pitch black in the garage so we do notice that delay.The alkaline batteries that we had in the light had been in that unit for almost a year and were still working but slightly dim. The C2 batteries were a bit brighter but not up to the full brightness of fresh alkaline batteries.I did a check of the batteries using one of those flexible strips that come with new batteries. The year old alkaline were holding slightly less power than the C2 batteries.I put one of these C2 batteries in my battery charger only to have it report voltage and current of the C2 battery but my charger behaved as if the C2 battery was faulty. I wasn't attempting to charge it but just wanted to gather some data. I really would like to be able to charge the C2 battery in my charger which can recharge up to 8 batteries at a time. I find the dual USB-C cables are not like the rest of the batteries in our house so they are a bit awkward.For my money this will be the last set of this type of lithium batteries that I'll buy.Pros:- Can power devices that demand 1.5V- The USB-C small split cable that comes in the box with the batteries coupled with the lighter weight of the lithium batteries may be beneficial for travel.- Fast charge times may be helpful but we don't complain about eneloop type battery charge times.Cons:- It seems alkaline batteries hold about 3X more power than these C2- These batteries are 3-4X higher cost than alkaline batteries. It may take a long time and a lot of use to regain the extra cost.- Can't charge in standard battery chargers.I'm sure there was a lot of engineering that went into designing these batteries but we can't find a practical use for them in our house.At this point I can't recommend these batteries.

I chose these batteries to have something to fit my most common regular battery devices that would recharge using the same cord I have for my phone and other larger power banks. Seems to be great for that as part of a power out backup kit.

Seems like they work well. Easy to charge. 1 battery of my 4 pack will not charge. Can't comment on battery life or charge time.

As an engineer, I have always had a problem with the design of my Duracell 1500 high-power LED flashlights (four C cells). Even new high quality alkaline batteries would only provide a number of minutes of sufficient power before their voltage fell below the switch-off threshold of the flashlight - darkness!These batteries, being both lithium and a higher voltage with regulated 1.5 volt output means that they provided a full 1.5 volts for many, many minutes. Fantastic! Then just recharge and start over.After testing one set of four in one flashlight, I am ordering a second set - even though they cost way more than the flashlight itself - they make it WORK. No more repeated purchasing of alkalines.