D Size Battery Specs and Maglight LED Conversion

Does anyone use the D size battery anymore? I do… It was my original Maglite battery size.

First released in 1979, the Maglight flashlight originally worked with 4 D size batteries. Although nowadays they make models that operate on AAA, AA, C or D-cell batteries. (And the MAG-TAC (amzn) flashlight that runs on lithium CR123 batteries).

I was going through my battery storage container inventory the other day to see if I needed to buy any new batteries, particularly the D size battery. I do have a handful of rechargeable D size batteries (see which one’s below). But how do they compare with the alkaline?

First, the energy storage capacity of a D size battery is enormous compared with the most common consumer battery (AA size). Sure, the D size is bigger, but it sure packs a punch.

BIG DIFFERENCE in energy storage!

D size battery capacity is typically 12,000 mAh (Alkaline)
AA size battery capacity is typically 2,700 mAh (Alkaline)

Why do they make a D size battery?
Answer: For devices that require a lot of power. It was a popular Maglight battery size.

Do you know what was one of the most common uses for the D size battery? (“was”)
Answer: Flashlights! (and ‘boom boxes’).

Times have changed though regarding flashlights. Back in the “old days” there was no such thing as LED flashlights. Flashlights back then mostly had incandescent light bulbs, and they sucked up a lot of power. You needed D size batteries to keep that flashlight going – especially if it had a bright bulb.

Today however the LED bulbs require MUCH LESS POWER (drastically less) to achieve equivalent light (lumens) output as the old incandescent bulbs. So the requirement for big D batteries is nearly gone for flashlights…

BUT! I thought of an interesting advantage:
Knowing that LED flashlights require much less power than old style flashlights, imagine how long a LED flashlight might operate with larger D size batteries??

How many of you have one of those full size Maglights from yesteryear?
I have a few, and they all take the D size battery (one of them takes 6 of those!). Did you know that you can get LED replacement bulbs for those Maglight Flashlights??

Do you know how long a converted Maglight will function with all those D batteries?
Even with the brightest LED replacement bulb the batteries will last about twice as long.

Maglite LED Conversion

I found what is apparently the brightest available replacement LED bulb for 3 – 6 D or C cell Maglight flashlights (360 Lumen).

This is what I bought:

Maglite LED Conversion Upgrade Cree 300 Lumen Bulb
(view on amzn)

>> All Maglight Conversion Kits

After thinking about it, I have just two types of electronic devices that take the D size battery. My old Maglights and several battery powered LED motion lights that I use inside my shed.