AA to D Converter

Flashlight Modding and DIY Parts
1

I was lucky enough to get a couple of the Defiant 3D 650 lumen lights and have them hiding under the driver seats of our vans. One of them replaces a Craftsman Maglite clone that died from leaking D cells. I’d like to have a light ready in each van without losing any more to battery failures. One option is to store the batteries seperate from the lights but that seems to be kind of “fidley.” Another option is to get adaptors and use Eneloops. Here are the ones under consideration: https://www.fasttech.com/products/0/10002008/1143900-2aa-to-d-size-battery-converters-2-pack, http://usd.dx.com/product/soshine-aa-to-d-size-battery-convertor-case-901003228, http://usd.dx.com/product/plastic-type-d-to-2-x-aa-battery-holders-green-2-pcs-901186704, http://usd.dx.com/product/translucent-2-aa-to-d-battery-converter-cases-2-pack-901022082, and http://usd.dx.com/product/yellow-aa-to-d-battery-converter-cases-2-pack-901128592.

Are there any practical differences between these for this application? Would they cause any difference in light output? Could I expect a couple hours run time? Any issues I’m not thinking about?

Thanks in advance for any insight.

2

You can purchase AA to D Eneloop adapers. Many places carry them. Here is an example:

Personally I’ve only used them on a lantern with no more than 1amp draw. It worked out perfectly well.

I’ve also used the generic 2AA to D adapters on 3D Maglite and it worked well.

I have eneloops in lights I keep in the car. I also have an extra set as back up. I charge them once a month if they haven’t been used.

Other questions about Defiant lights I can’t answer. Hopefully more experienced members will chime in on that.

3

I have used the Eneloop adapters that take one AA cell and converts it to one D cell. The problem is that the spring on the device that contacts the negative end of the AA cell may be a bit large for a smaller diameter cell. I have solved this problem with a piece of sheet aluminum bent into a horseshoe shape, and placed into the negative end of the adapter. Also, the cell wiggles around a bit in the adapter.

The adapters that you have linked will increase your chance for resistance from the cell to the adapter. Four extra points to flow the current through, for each adapter. If you have more resistance on one cell of the two, I think you may have the effect that battery makers warn you about. Namely, use all new equivalent cells. Maybe that’s why Eneloop has adapters that take only one AA cell and the negative end of the cell is in contact with the device.

I bought these, link edited for correct vendor:
http://www.ebay.com/itm/Sanyo-Eneloop-Battery-Adaptor-Converter-AA-to-D-R20-x8-/330695346319?pt=US_Battery_Converters&hash=item4cfefa888f

4

Tenergy D LSD cells.

By the time you add up the cost of Eneloops plus good quality adapters you might as well get 8AH D-cells and have plenty of runtime, about 3 sets of Eneloops worth.

5

Here is another optionm 3AA to 1D parallel adapters: http://www.ebay.com/sch/i.html?\_trksid=p2050601.m570.l1313.TR0.TRC0&\_nkw=3+AA+to+1+D&\_sacat=0&\_from=R40

6

DEFINITELY! I’ve seen those adaptors go for $6-$10 for ONE 3AA/D adaptor ALONE. This may not sound like a bad deal until you consider that you can get 8000mAH Tenergy Centura D cells all day long at Fry’s for $16.99 a pair (or $15.99 at All Battery, but you have to pay for shipping if you don’t live in the Bay). Of course, you also have to consider all the other advantages of using real D batteries instead of AA batteries in adaptors, such as increased capacity, decreased resistance, better reliability (these adaptors just seem flimsy), the convenience of charging just a few D cells rather than a boatload of AA batteries, etc. When you consider all of this, adaptors just aren’t the greatest idea, except maybe for emergency use.