some questions

hello, just new here. have some questions that keep confusing my choice of lights (surefire). hope you can help. thanks!

1. how long can each eg. 60 lumen lamp, led versus bulb, maintain a brightness of 60 lumens with brand new batteries? or how would one compare with the other given this scenario.

2. a brand new, unused, battery has an expected life of about ten years. if used once in the first year (with 10% energy usage/consumption), how much energy would be left by the fifth year? or by how much would the rate of energy loss compare with a new and used battery?

3. how does led compare to bulb? energy usage, light output, performance, color?

Hi, Brawnless.

I will try to contribute only based on what I know, someone more knowlegable could probably answer them better--

1) For 60 lumens, say SF brand lights, I think the spec says an hour; and my result is about the same give or take(G2Z, since I never leave it straight on to measure the output). As for LED, that will depend on the electronics, what kind of LEDs, and batteries. For rough references, you could check out a table for 'sandwich' from Shoppe.

2) IIRC, the Li-ion does have an extensive shelf live. Though I never tested it myself, I would suspect a partially used one will not loss its capacity quicker just because it had been used. My educated guess for a brand new Li-ion cell would loss less than 10% over the decade.

3) LEDs do come in varoius color, and what you will commonly see on this forum is called the Luxeon LEDs. They are genuinely a little more 'durable' than bulbs(for ex, dropping on the floor when lit on), and generate a little less heat if it is not overdriven. The white colors do have various 'tint', and you probably could find a lot more info reading from this forum. It is hard to say what is 'better' since these two have their own usage--for better color retention, fog/rain cutting power or really long throw beam, I would prefer bulb over LED for sure since the bulb light does not get 'washed out' by ambient light sources; but for variable brightness, durability and long burning time, LED does have great advantage.

Hope this helps. /ubbthreads/images/graemlins/smile.gif

Hey there, Brawnless.

I do not consider myself particularly knowledgeable (especially compared to many of the gurus around this site) but I will try to add some more info...

(1) I think in general, LEDs are able to get more runtime than incandescents given the same lumen output. If you are worried about a consistent light level then a good thing to check is to see if the flashlight is regulated. A regulated flashlight has circuitry in it to keep the voltage supply to the lamp at a consistent rate so the light level is consistent throughout the useable life of the batteries. If the light is not regulated, then light output will slowly diminish over time as the batteries become depleted. For example, I have a G2 (incandescent, unregulated) and an L4 (LED, regulated) and both have a listed runtime of 60 minutes. The G2 slowly dims over time as the batteries run down while the L4 remains consistently bright until the batteries run down to the point that the boost circuit cannot keep up at which point it switches to a lower level output.

(2) Not sure about this one since different battery chemistries have different self-discharge rates. I would suggest poking about the Flashlight Electronics - Batteries Included forum of this site for more information.

(3) LED flashlights usually have better runtimes than comparable incandescent flashlights and are more shock resistant due to their construction. Note however that LED based flashlights have more complex driver circuitry associated with them so when they do break, the fix is not as simple as popping in a replacement bulb. Color rendition is usually better with an incandescent than with an LED.

As people like to say around here, your mileage may vary (YMMV). The best thing really is for you to find a local shop that has both incandescent and LED flashlights for sale and try them out yourself to see what works out best for you. Though if you have a specific purpose in mind, feel free to share what exactly you are looking for and there is a good chance that the friendly folks here on CPF will help you get the flashlight you need.