Whizzotech Parallel AA to D Battery Adapters Holder 1.5V Output Case Box 3 AA to 1 D Converter (12 Pack White)

(1) Application.(a) I have a number of LED flashlights (Maglite) and lanterns (Rayovac Sportsman and Streamlight Siege) that use D cells. These units are typically stored for standby use in environments with uncontrolled temperature and humidity (e.g., in cars or garages). They are typically stored for extended periods, one or more years. If I use regular alkaline batteries, even good quality ones, they invariably leak, and damage or destroy the units.(b) I have smaller LED flashlights and lanterns that use AAA or AA cells. For these units, I have switched from alkaline batteries to Eneloop rechargeable NiMH batteries. So far, I have not had any Eneloop battery leak, even with units that have been stored in a car for two years. Unfortunately, Eneloop does not sell D cell rechargeables. There are other brands of rechargeables that do come in D cells, but reviews indicate they are not as reliable as Eneloops. Eneloop does make a AA to D cell adapter shell, but it holds only a single AA cell. The capacity of a single AA Eneloop (~2000 mAh) is skimpy compared to that of a (non-Eneloop) D cell rechargeable (~10,000 mAh). The key advantage of these Whizzotech adapters is that they can hold up to three AA Eneloops in parallel (total capacity ~6000 mAh).(2) Design and Use.(a) A Whizzotech adapter has a tough plastic shell with plated metal electrical contacts. On the outside of the shell, the electrical contacts mimic those of a D cell: the positive contact is ~7/8” diam with a central raised dimple ~5/16” diam at its base; the negative contact is ~7/8” diam with a central raised ring ~5/16” diam.(b) On the inside of the shell are three chambers, each accommodating an AA cell. In each chamber, the positive contact is a rectangular strip; the negative contact is a coil spring.(c) An Eneloop AA cell fits just right into a chamber. No excessive force is needed for insertion. Yet the cell is held firmly: if the adapter is shaken, the cell does not fall out. One, two, or three AA cells can be inserted into an adapter.(d) If only one or two AA cells are inserted, they can be readily removed by inserting a finger into an empty chamber and pushing out a cell from the inside. If all three AA cells are inserted, removal is more difficult. An easy and safe method I’ve come up with is to use a small wooden “popsicle stick” as a removal tool. This is a wooden stick ~3/8” wide X 1/8” thick X 5” long, with rounded ends. If you don’t eat popsicles, you can buy such wooden sticks at arts and crafts stores. Each chamber for a AA cell has a recess for the positive terminal. If you insert the rounded end of the wooden stick into the recess, you can readily pop the AA cell out. This method is a lot safer than inserting a screwdriver tip into the recess to pry the cell out, and a lot simpler than wrapping a strip of ribbon or tape around the cell to pull it out.(e) The D cell adapters fit into a 2-cell LED Maglite, a 3-cell LED Maglite, a 3-cell Rayovac Sports lantern, and a 3-cell Streamlight Siege lantern without any issues, either in terms of mechanical fit or electrical contact. In particular, the large diameter negative contact on the outside of the adapter is essential for proper electrical contact with the Maglite flashlights: the negative contact in the end cap of the flashlight is a coil spring; the diameter of the end coil that contacts the adapter is ~3/4” diam. Adapters with small diameter negative contacts will require modification for proper electrical contact, but not these Whizzotechs.(3) Manufacturing Issues?(a) I found only one minor manufacturing issue. It was readily fixed, so I didn’t ding any stars. I ended up buying 24 of these adapters. In 8 of these units, the positive contact for the AA cell in one or more chambers was sticking up, instead of being pressed flat. They were easy enough to press down with a finger tip.(b) Otherwise:* No sharp edges on the plastic or metal parts* No manufacturing crud* No corrosion on the metal parts* No defective coil springs in the negative contacts of the AA cell chambers.

I read the reviews on these and other AA to D converter/adapter options. Am I glad I went with these. Of course they are parallel so they don't increase the voltage, just increases the mAH available versus a single AA to D adapter. It is a "D cell replacement" so it's going to be approximately 1.5v no matter how many batteries you do or do not use per adapter.In my case, I decided to replace the 3 D cell batteries in my classic 3D Maglite as well as upgrade the bulb to a modern LED (I had upgraded it to LED a few years ago already). After doing iterative testing and subjective comparative analysis of these adapters with only 1, 2 or all 3 AAs installed in each adapter vs 3 full D batteries, I find no output difference in any of the configurations.I love that you can use a single AA in each adapter. That can be especially useful if you're in an extended power outage situation and you have to split or share batteries between multiple devices. Obviously if you use fewer AA batteries, I will have shorter run times but I'm not locked into using 9 AA batteries for my Maglite. I can get by with as few as 3 AA batteries.Anyway, the quality of the plastic is higher than I expected. I have purchased a number of devices in the past that use AA or AAA batteries in a plastic adapter to increase the voltage for the device and each one of those adapters feels very cheaply made and very thin on the plastic walls. These adapters are substantial in their use of plastic. The metal contact plates are thin but should be quite serviceable considering they should spend their lives inside a device of some sort.I'm quite pleased with the purchase and will be purchasing more to further remove D cells from my life.

The design is better than I expected given the price point of $1.25 each in a quantity of 8. I purchased the white unit that has the coil spring base.The plastic is smooth, sturdy and slides freely even in the tight confines of a Maglite Flashlight. I applied a moderate twisting force and was not able to deform or crack the plastic. The three framing pillars are solid plastic, not hollow, and feels like polyethylene. The springs are clamped on and on a random sample of 2 units, provided a secure connection. The metal appears wide enough to deliver the maximum currents available from any AA-class battery without substantial heating. It would be superior if the springs were soldered to minimize voltage drop, but that can be a post-purchase modification that is not difficult for an experienced expert.Whether 1, 2, or 3 AA style cells are used, this package will always provide the typical 1.2-1.5 volts. The choice of the number of batteries installed allows the current supplied to be divided across multiple cells to prolong their service life. As the addition of two or three additional batteries provides more current, batteries of different charge levels should NEVER be mixed in the same 3-cell package. Likewise, a mixture of technologies (Alkaline, Ni-Mh, Ni-CD, Rechargeable Alkaline, or heaven forbid - Heavy Duty) should never be done as there is variance in nominal voltages that will cause the cells to self-discharge or potentially destruct in a catastrophic failure due to unrestricted current from one cell to another.The polarity + and - symbols are embossed in the on the ends of each unit. The polarity of the containing cells matches that of the entire unit.

Using to power Streamlight Siege LED 3D Cell Lantern. These holders are of very high quality. I have alot of eneloop aa 2100 mAh Ni-MH cells, so this product let's me choose to use 1-2 or 3 batteries in each holder. The more cells you put in the longer the battery life. These holders make 3 AA cells in parallel to equal th energy of 1 D cell. Perfect for my application. Can be used for any AA battery Alkaline, Ni-MH, li-Ion. Ddo not mix battery chemistry types, keep all the same mAh rating for all cells. This my best alternative to costly D Cells.

Exactly what I've been looking for. I wanted an adapter that took multiple aa's, I purchased some to the very cheap clear plastic ones you can find here on Amazon, or on eBay, but they are very cheap and don't last. When I found these I shouted for joy, and when I got them and put them to the test I shouted even louder, they are solidly built, hold 3 batteries and will last a long time... HIGHLY RECOMMENDED

These work as intended, and seem very sturdy. I expect never to have to buy D cell batteries again. I've been using these with 1, 2 or 3 AA rechargeable batteries in each adapter. Obviously mixing quantities in one device is probably a bad idea, but if you put one AA battery in each adapter it works fine for my devices (though not as long, of course). 3 in each lasts much longer, and it's really great that this adapter can take 3 AAs.

These work well - hooking up three AAs in parallel to properly replicate a D cell. The only issue is getting the batteries out if you have to, I need to use a screwdriver to pry at one of them, the others then can be pushed out from behind.

These work, but you have to fold down the tabs on the positive terminals first. They aren't compressed sufficiently from the factory. Those tabs can cut through the insulation at the top of the AA cells and short out the positive terminal to the case.

A little flimsy, but work as intended.