Quote from: Fungus on Today at 07:32:49 PM
>Quote from: samgab on Today at 06:58:11 PM
... Such as the SC5 AA, for instance:
Let me guess: You own that model.
My EDC is a Fenix LD01 - same as Dave Jones. It's truly keyring size and runs on a single AAA battery - none of that bulky, high-current, AA cheating.
Quote from: samgab on Today at 06:58:11 PM
this one does it really well, with a super flat output "curve" or straight line, as the battery discharges right down to 0.7V.
Why is it much brighter for the first 17 minutes? That doesn't seem like "super flat" to me.
Hey, I don't have the SC5, although I do have an SC600 which runs on a single 18650, is also tiny, and puts out insane amounts of light, but that one didn't seem appropriate to this discussion about Alkaline AA batteries.
As for the brighter initial output and then the flat line... that is by design... It drops to a lower mode of output when battery voltage reaches a certain point. But I was trying to highlight the regulation mainly. There's no curving down, it just runs as a straight line then drops off like a brick wall between modes.
When you look at the full review though, and see the output charts for Eneloops for instance, it stays at full output longer, although it still drops down to those same levels after a time, but spends less time running at the lower levels (It's probably to do with the internal resistance of the Alkaline cells compared to the NiMH cells. I don't think the Alkaline chemistry can sustain the output current required to keep the max output going long. I'd like to see some tailcap current measurements):
The LD01 is a neat little torch, again, amazing performance for a single AAA. My EDC keychain is a 4Sevens Preon0, same form factor. But I wasn't sure if they are fully regulated or if they use PWM. I think they're regulated too. I also have a Fenix LD20 which also has great regulation.
But yes, regulating AA and AAA cells to get steady performance and to use all of the energy in Alkaline cells is nothing new.
Also check this review
http://lygte-info.dk/review/Review%20Fenix%20LD01%20SS%202010%20UK.htmlof the LD01.
Check out the regulation shown by a voltage sweep (you have to read it backward):
Notice how the current climbs way up to nearly 2 Amps as the cell voltage dips down to 1V! That's just to maintain a constant(ish) light output, and there is a max Power draw of nearly 2W!
This gives an idea of what the batteriser would have to do to keep a constant voltage output at 1.5V although it has to maintain it right down to 0.6V, not just 1V input voltage. (to stay on topic
)