bpierce
Newly Enlightened
- Joined
- Nov 13, 2014
- Messages
- 17
I mentioned NiCads only because that is what was in the satellite power supplies that I had been involved with. This was 20 years ago. Interestingly, a satellite that was launched with our power system came back to earth a couple of years ago. I think they got over 15 years of operation from those nicads. Not bad for going through a charge/discharge cycle every 90 minutes! It wasn't a full charge/discharge, but that's still a lot of use.
Supercaps are pretty big, but I used a nice supercap from Bussman-Cooper in a recent bicycle light design. 100F at 2.7v. Not too bad at all. Larger than a AA, but will run a LED at a decent level for 10 minutes using a little boost converter from Zetex (now Diodes Inc.). This gets back to a fundamental question: what is the spec for run time and for output level? Is this light supposed to let you go find a real flashlight that is in the next room, or is it supposed to run at 3 watts for a few hours?
See my reply below to Fireclaw18. Based on a lot of feedback I've gotten, I'm thinking I'd target an output of roughly 250 lumens and a run time of 45 mins to an hour for an initial release; also I like the idea of using an LiFePO4 battery. That amount of output is probably enough to help people get around in an emergency, so if I have room within a reasonable cost to ramp something up it would be the run time. I suspect many of my customers won't have a better flashlight in another room, so better if mine can last as long as possible (but if it's too expensive, they won't buy it in the first place!). I'd love to go tend toward premium specs, and maybe eventually can have a premium line, but that might be a tougher market since the people who would buy a premium Flashlamp probably don't need one . Maybe I should be targeting a much longer run time out of the gate given that luminosity?