General questions

Hi - I'm kinda new and wondered if you guys could help me with the following questions...brought about by wandering around the site

1. The brightness bin code for luxeons (R, T, etc) - is this another way of describing the efficiency of the led? In other words, the higher rating is correlated with higher efficiency and that all the led's in a 1 watt category for example, would draw the same current.
2. When we worry about frying an led because we want to use a rechargeable li ion, is there a formula to determine if we are close. The H bin led's seem to be a good choice for rechargeable li ion (3.7v) batteries which implies there is about a 0.7v tolerance. Or is it really that the higher voltage means that together with the increased amps, we are overdriving the emitter and at some point it fries. Is there a rule or guideline on how much you can overdrive before frying?
3. Concerning 3v rechargeables - if I want to minimize the number of chargers, it would seem that you could use the 3v rechargeable charger (which I believe terminates at 4.4v) with a protected 3.7v RCR123 (for example). The protection circuit could prevent the 4.4 v from harming the rechargeable battery - or would it prevent it from charging in the first place.

Sorry if any of this is unclear or just plain dumb.
Sam

Welcome to CPF.

Hrmm...

1. The different bins (first letter of a TW0H example)... the T inticates that when given a certain amount of current, it puts out brightness within a certain range. This can be tricky because theorhetically you could have a Lux III S bin and a Lux III T bin that are only .1 or .2 lumens different. Most of the T bins I've seen have been consistantly pretty bright, but I've seen really crappy S bins and I've seen S bins that looked as good as most T bins that I've used.

2. The last letter of the bin (H in the above TW0H example) is the forward voltage. The higher the letter, the more voltage it pulls. Usually, the higher the letter, the less likely it is to be killed or fried regardless of how it is powered if that makes any sense. If you get comfortable with swapping stars, then it's not really a big stretch to think that you can run a given light on a R123 and if it dies after 100 hours, just swap another one in. The cost savings of using R123s vs primary 123s justifies it to me. You just need to use caution and common CPF-garnered sense.

3. I've never had any of the so-called 3V R123s but I was of the understanding that some of them just wouldn't charge at all on a standard '3.7V' LiON charger. I don't know if the opposite is true or not.

Hope this helps a bit and doesn't leave you any more confused than before. Perhaps if you gave us specific things you were thinking about, it might make it easier for us to give you more specific advice.

Thanks, appreciate the response - I am just trying to make sure I understand the concepts so that I can be more informed.

For example, I was wondering why people wanted the VB-16 5w version when there were comments indicating that at full brightness, the 3w version got very hot. It would seem to me that the 5w version would therefore get even hotter unless the heat sinking were better. Perhaps the efficiency of the 5w is better so it could pump out more lumens at lower heat levels...in any event, thanks