I have a Dorcy 41-1642 PR LED bulb, which is currently placed in a 2-D flashlight. Here is a scan of the bulb's packaging, stating its output and current consumption for different voltages. I also have an equally suitable 3-D flashlight currently using a PR Krypton bulb.
My question is, and this might seem confusing: using the Dorcy LED bulb, if there is a long power outage and I only have 6 alkaline D-cells available (I stock more, but for simplicity's sake, the rest are stolen), would my total runtime be better if I used the bulb in a 2D flashlight, or a 3D flashlight?
From my calculations, I believe there is greater runtime from using the 2D flashlight. Even if I am right, however, I'd like if someone could review my work. Note: I have made some "guesstimates" and assumptions based on what I know, and I have approximated values inferred from the data linked above, so be prepared to correct me and maybe yell at your monitor.
Assume: D-cell will use 15,000 mAh at approximately constant voltage, not including the mAh used during the inevitable voltage sag (which will be ignored, but, maybe it shouldn't be).
Assume: Current Draw at 2.4V is somewhere between 425 and 440 ... I'll use 430.
Assume: Current Draw at 3.6V is somewhere between 370 and 390 ... I'll use 380.
2D Light - Current draw of approximately 430mA while operating at 2.4V
- 15000 / 430 = 34.9 hrs.
- 34.9 times 3 sets of D-cells (2-cell flashlight) = 104.7 hours.
3D Light - Current draw of approximately 380mA while operating at 3.6V
- 15000 / 380 = 39.5 hrs.
- 39.5 times 2 sets of D-cells (3-cell flashlight) = 79.0 hours.
Greater runtime seems to be had from using this bulb in a 2D flashlight than a 3D flashlight. However, I know these are rough calculations, and I am curious to know if I am "close enough" to a correct answer. Thanks!
My question is, and this might seem confusing: using the Dorcy LED bulb, if there is a long power outage and I only have 6 alkaline D-cells available (I stock more, but for simplicity's sake, the rest are stolen), would my total runtime be better if I used the bulb in a 2D flashlight, or a 3D flashlight?
From my calculations, I believe there is greater runtime from using the 2D flashlight. Even if I am right, however, I'd like if someone could review my work. Note: I have made some "guesstimates" and assumptions based on what I know, and I have approximated values inferred from the data linked above, so be prepared to correct me and maybe yell at your monitor.
Assume: D-cell will use 15,000 mAh at approximately constant voltage, not including the mAh used during the inevitable voltage sag (which will be ignored, but, maybe it shouldn't be).
Assume: Current Draw at 2.4V is somewhere between 425 and 440 ... I'll use 430.
Assume: Current Draw at 3.6V is somewhere between 370 and 390 ... I'll use 380.
2D Light - Current draw of approximately 430mA while operating at 2.4V
- 15000 / 430 = 34.9 hrs.
- 34.9 times 3 sets of D-cells (2-cell flashlight) = 104.7 hours.
3D Light - Current draw of approximately 380mA while operating at 3.6V
- 15000 / 380 = 39.5 hrs.
- 39.5 times 2 sets of D-cells (3-cell flashlight) = 79.0 hours.
Greater runtime seems to be had from using this bulb in a 2D flashlight than a 3D flashlight. However, I know these are rough calculations, and I am curious to know if I am "close enough" to a correct answer. Thanks!
