****** - Verified Buyer
4.5
(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.
