KevinL
Flashlight Enthusiast
Just scored an E2DL from the marketplace 
Now comes the question of what to feed it.... I know it doesn't run in full regulation on a single 17670 and would probably benefit best from a 2-cell configuration. Now comes the tough question of what to feed it.
I've been considering a switch to safer chemistry lithium cells, but with that comes a price in terms of capacity.
A few back of the envelope numbers for reference:
2 x primary 123: 6 watt hours (WH)
1 x 1600mAH 17670 = 5.92 WH
And my choices:
2 x 750mAH R123 = 5.55 WH
2 x 550mAH R123 IMR = 4.07 WH (27% less)
2 x LiFE 500mAH R123 = 3.2 WH
I'm probably not going to use LiFE because the energy density is just way too low, plus their 3.2V voltage means even less watt-hours.
As it is, going with IMR vs LiCo R123 already means a 27% hit in terms of juice. Worse if you compare to primaries: we're looking at 33%. So 2 hours is going to become 80 minutes on IMR. 80 min is still within acceptable runtime for me, not so long ago we used to be walking around with lights that would run flat in under an hour.
The IMRs have one advantage though: should an emergency happen and I need to run the light flat into the ground, I can do so on IMR because they have no protection circuit. Of course I'll never be able to charge them again - well, treat 'em as disposable cells. LiCo protected cells would cut off the circuit and douse the light.
Is the additional safety advantage worth it?
Now comes the question of what to feed it.... I know it doesn't run in full regulation on a single 17670 and would probably benefit best from a 2-cell configuration. Now comes the tough question of what to feed it.
I've been considering a switch to safer chemistry lithium cells, but with that comes a price in terms of capacity.
A few back of the envelope numbers for reference:
2 x primary 123: 6 watt hours (WH)
1 x 1600mAH 17670 = 5.92 WH
And my choices:
2 x 750mAH R123 = 5.55 WH
2 x 550mAH R123 IMR = 4.07 WH (27% less)
2 x LiFE 500mAH R123 = 3.2 WH
I'm probably not going to use LiFE because the energy density is just way too low, plus their 3.2V voltage means even less watt-hours.
As it is, going with IMR vs LiCo R123 already means a 27% hit in terms of juice. Worse if you compare to primaries: we're looking at 33%. So 2 hours is going to become 80 minutes on IMR. 80 min is still within acceptable runtime for me, not so long ago we used to be walking around with lights that would run flat in under an hour.
The IMRs have one advantage though: should an emergency happen and I need to run the light flat into the ground, I can do so on IMR because they have no protection circuit. Of course I'll never be able to charge them again - well, treat 'em as disposable cells. LiCo protected cells would cut off the circuit and douse the light.
Is the additional safety advantage worth it?
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