Hello MikeSalt,
AWs protected cells won't light up a 1794 very well, or at least not on a single click. On the P91 they will fire it up if you dance on the tail-cap once or twice. The 1794 is even a heavier load than a P91.
Thing is, on the larger cells with the same 5 amp limit, the cells can deliver large "bursts" of current to warm up the filament before the protection "catches" it. The RCR123 is basically running like a dead short into a cold filament and is giving up everything it has to warm up the filament, but it won't be enough to warm up the filament in one try before the protection circuit jumps in and says "hey, what do you think you are doing here. trying to murder me?". So that's when the user responds, "YES, DIE DIE DIE," and keeps pushing the button to cycle the protection on and off until the filament warms up enough to run continuously!
protected cells won't work for his intended purpose, no protection circuit is going to make this a much safer setup. Probably won't work anyways... For as much light as possible, unprotected is really the only way to go here. Protection circuits take up space, make the actual cell smaller, and add resistance. In every normal configuration I heavily recommend protected cells. In this case, assuming a protected cell that would allow that much current to flow, it would really only delay the inevitable. The cells will fail in a few cycles.
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Yankeefist,
I'll be nice now
Sounds like you are well aware of what you are doing. Provided you understand the risks allow me to try to reduce the risks as much as possible... (nnonooo.... cut the BLUE wire.... lol)
The best things he can do is limit use to short bursts of output. I'd say, 10 seconds or less whenever possible. Since you're mostly just using it to wow people, wow factor can kick in pretty quickly, a few flashes of bright light should have people wondering where you are hiding the nuclear accelerator. Keep it short and sweet, get some bursts out of it, then get it back to the charger. Get it back on the charger when the open circuit voltage of the cells drops to ~3.90-3.95V. Try to keep the cells in the top 20% or so, never doing a full discharge on this load. I would probably recommend limiting charges to 4.15V as well, but that's up to you, if you want it really as bright as possible, 4.20V may be preferred.
If you follow this regiment of shallow cycles, you will probably get around 25-75 cycles out of the cells. If you were to do a continuous discharge to the point of being "dead" (~2.5V under load) and charge them back up each time, the cells would probably last less than 5-10 cycles.
Put your charger in a fireproof box in a well ventilated area. Cells being abused that hard are usually safe during the discharge, and are most likely to vent while charging.
it will probably be difficult to determine when the cells have aged to a point that they need to be replaced, as I'm betting they are going to develop very un-even internal breakdown that may or may not show it's signs the same way cells used normally would, with that in mind. You may consider replacing the cells after awhile even if they appear to be working fine.
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As for the ROP vs 1794... there are a few things to consider as possible:
Ultrafire cells are known for problems, I've seen test results ranging from respectable to pitiful on them. Could be that you got one of those pitiful duds with abnormally high internal resistance.
Try to get yourself a pair of Emoli 18650s for the ROP, they will be safer and the results will be much better, and if it still isn't working that great, you know for a fact that it's not the cells fault. Work on resistance.
I love it
