LENMAR PROAA2D 2-pack D Size Batteries Specifications: The Power of D size cells, using the AA cells and charger you already have! Snap-in design makes inserting and removing your rechargeable AA cell easy Uses any standard AA size rechargeable NiMH cell
I've used a similar product by Panasonic which was MUCH better made, but I haven't found the Panasonic brand adapters sold outside of a Costco rechargeable battery kit.The 4 Lenmar AA-to-D adapters do work but they are inconsistent in how well your AA batteries fit inside. 2 of the 4 adapters worked normally for me while the other 2 were too loose or the AA battery didn't snap into place when inserted - and I tried several AA batteries with the same results.These Lenmar's are cheaply made but they will work..
These have failed to work for me in every item where I have tried to use them. The problem was that they did not make electrical contact with the metal springs inside the battery compartment. If you compare these adapters with a real D size battery, you will see that the typical real battery has much larger metal areas for the springs to touch.It's a nice idea and I'd love to find some adapters with a better design but these unfortunately fail the test. Buyer beware.
If you have some power-hungry applications that require D-cells, you can usually save money in the long run by using rechargeable NiMH cells instead of alkaline cells. One approach is to buy a set of AA to D-sized adapter shells, and use rechargeable AA NiMh cells in those. This is the cheapest method because AA NiMH cells typically cost less than ten dollars for a package of four, and you can use low-cost AA charger for them (instead of buying another charger that accepts D-cells).However, don't expect to ..