Summary: something around (maybe over) 2 hours on high from a lux v U2, before the U2 starts kicking the output down. 4 hours to recharge on a good dealextreme charger that I'll unplug and remove the battery from when charging is done. Happy about the purchase and I'll keep my remaining 123a cells as backups.
Details for the record:
Bought the RCR18650 from jtsgalaxy, more info in this thread: https://www.candlepowerforums.com/posts/3014456
Bought this 18650 charger on his advice (which jived with other advice I've read): http://www.dealextreme.com/details.dx/sku.6105
Previous U2 runtime graphs with 2400mah cell (1:40 on high): https://www.candlepowerforums.com/threads/128188
It cost me around $15 for the cell and $7.50 for the charger. The cell I got is one he's already used for testing, so any extra performance juiced from his recommended discharge-recharge conditioning is present in this cell. This cell is one without the underline under the main RCR18650 text on the label.
I don't have any way to measure light output, and I wasn't going to sit around staring at the light for hours to tell exactly when it went out. I just wanted to get an idea of how long it would last in my original circa-10000th-unit luxeon 5 / luxV U2, just enough information to pass along. Full power from the U2 is something over 1A. It was cooled during the test in a container of room temperature water.
U2 output does change over time, but the regulation stayed close to the highest brightness stage for something around (over, I think) 2 hours.
After that time it stepped down to a medium light level for another 2 hours.
2 hours later (hour 6) it dropped down to some brightness around the lowest level.
Another 1.5 hours after that it started flickering. For extended use I could dial it down to level 1, and it would stay at that level acting normally for some extended period of time. I'm guessing a couple more hours at least, but I hope to never need to find out.
At this stage the battery is at 3.18v outside the light. Surprisingly high to me, but I don't know exactly how this stuff works. Jtsgalaxy says these li-ions can run below the previously typical li-ion minimum voltage of 2.9v-ish, down to 2.5v or so. Well you'll never find out with a U2, I guess! U2 allegedly cuts off service around 3.1v anyway.
The cell doesn't seem to get warm at all when charging. It took 4 hours to go from 3.18v to completed at 4.21v. I believe leaving it on the dealextreme charger for some time after the light turns off will bump the voltage up to 4.24v which then cools down to 4.21v or so after sitting off power for a day. So the charger is up to snuff, but I'd take the battery off and unplug it when the charge is done.
Overall a good 18650 cell for a good flashlight, from first impressions. I used primary lithiums up until now, not 18650. But I know this is better performance than older 18650 cells I've read about. The output certainly matches the primaries in my eyes, and it lasts longer too. Good fun!
Details for the record:
Bought the RCR18650 from jtsgalaxy, more info in this thread: https://www.candlepowerforums.com/posts/3014456
Bought this 18650 charger on his advice (which jived with other advice I've read): http://www.dealextreme.com/details.dx/sku.6105
Previous U2 runtime graphs with 2400mah cell (1:40 on high): https://www.candlepowerforums.com/threads/128188
It cost me around $15 for the cell and $7.50 for the charger. The cell I got is one he's already used for testing, so any extra performance juiced from his recommended discharge-recharge conditioning is present in this cell. This cell is one without the underline under the main RCR18650 text on the label.
I don't have any way to measure light output, and I wasn't going to sit around staring at the light for hours to tell exactly when it went out. I just wanted to get an idea of how long it would last in my original circa-10000th-unit luxeon 5 / luxV U2, just enough information to pass along. Full power from the U2 is something over 1A. It was cooled during the test in a container of room temperature water.
U2 output does change over time, but the regulation stayed close to the highest brightness stage for something around (over, I think) 2 hours.
After that time it stepped down to a medium light level for another 2 hours.
2 hours later (hour 6) it dropped down to some brightness around the lowest level.
Another 1.5 hours after that it started flickering. For extended use I could dial it down to level 1, and it would stay at that level acting normally for some extended period of time. I'm guessing a couple more hours at least, but I hope to never need to find out.
At this stage the battery is at 3.18v outside the light. Surprisingly high to me, but I don't know exactly how this stuff works. Jtsgalaxy says these li-ions can run below the previously typical li-ion minimum voltage of 2.9v-ish, down to 2.5v or so. Well you'll never find out with a U2, I guess! U2 allegedly cuts off service around 3.1v anyway.
The cell doesn't seem to get warm at all when charging. It took 4 hours to go from 3.18v to completed at 4.21v. I believe leaving it on the dealextreme charger for some time after the light turns off will bump the voltage up to 4.24v which then cools down to 4.21v or so after sitting off power for a day. So the charger is up to snuff, but I'd take the battery off and unplug it when the charge is done.
Overall a good 18650 cell for a good flashlight, from first impressions. I used primary lithiums up until now, not 18650. But I know this is better performance than older 18650 cells I've read about. The output certainly matches the primaries in my eyes, and it lasts longer too. Good fun!
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