Sharpshin

Well, I've had several student projects over the decades testing rechargeable batteries, seems they do lose capacity with multiple recharges, or used to.

In the meantime I was in the Peace Corps years ago and I have taught selflessly in a troubled urban school for going on thirty years....

Besides the booze and women and all that I'm hoping my karma can withstand a bucket or two of batteries in the landfill.

Eight hours and thirty one minutes on that battery and still going strong.

noglider 

I've bought too many $10 and $30 and $70 battery headlights. I stopped buying them when I started installing dynamo lights. Now I hate worrying about batteries. Yesterday a battery light went dim at an inopportune time. Grr. Once I got dynamo lights, I stopped spending money and taking care of lights. They just work, all the time.

Sharpshin

OK, I shut off the light after 12 hours, at which time it was still painfully bright to look directly at, apparently as bright as when I started. Again this is on the dimmer of the two constant-on light settings.

Still on the first battery, I will resume the test on Monday am.

2manybikes

Read the description and specs very carefully.

Those lights will operate with a higher voltage lithium battery the same size as an AA that may give closer to 400 lumens, since that is not close to possible with one AA battery. They intentionally make it hard to find, so you will believe 400 lumens from one AA. The more I read about the lights for sale the more I notice this is very very common. I've learned to know already just by looking at the ratings. I have done huge amounts of reading specs for lights from Places like DealExtreme and Amazon. I have a lot of AA lights single and doubles. A double AA light can give decent run time and power for a bike light. A two battery AA light from Fenix or Nitecore will be a great light. My favorite AA light is from Nitecore,It has a dimmer ring that twists and is max 280 lumens. I turn it down a little and get three hours with plenty of light. You can turn it way down as "be Seen" light and get much more runtime. I carry mine on every ride as a backup, or primary light if I stay out long.

This is similar power for $44. Amazon.com: Nitecore EA2 Explorer Flashlight, 280 Lumens, 2 x AA: Sports & Outdoors

Sharpshin

Just a follow-up. No school here on Monday (Martin Luther King Day) so I didn't get to test until Tuesday.

Tuesday morning, after staying constantly lit on the low setting for 12 hours on Friday until I shut it off, the headlight would not light at all on that battery Tuesday morning.

I dunno the intricacies of the internal chemistry in a AA lithium battery. It has been my experience in both flashlights and digital cameras that they quit suddenly and without warning. In this case the battery was apparently unable to summon the wherewithal to light up the LED element. I'm guessing the voltage requirement for startup is higher than that required to maintain the light-emitting condition.

So at this writing I have no clear idea as to how long you can run one of these batteries and have it light up again. I'm gonna guesstimate ten hours?

PatrickGSR94

My Cygolite front light with a proprietary 18650 li-ion cell gradually dims as the power is depleted. Not sure if that's a property of the battery itself or a result of the electronics within the light.

langdon

I have one of those Cree lights but not bike use. Its good for an emergency home or car flashlight but I don't think its going to compare in brightness to the lights developed specifically for cycling.

a1penguin

Cree is not a light, though. It's the manufacturer of the LED that is in a large fraction of LED lights/flashlights out there. The characteristics of cycling specific lights is about beam shape, weight, waterproof, mounting.

A well designed light will good regulation which provides relatively constant output with a sharp dropoff. Home | BudgetLightForum.com will have flashlight reviews that often show the lumens as a function of time. It's a great resource if you are interested in flashlights.

jfowler85

It doesn't matter what the light is reflecting on, there is no possible way a car is going to see your light in the wash if its own headlights. I know my bike's headlight is pointed too high when cars start flashing their brights at me...that's pretty much how bright you want your light.