700mah battery for g2?

[mojeb21]

got a g2 and im adding an R2 bulb from dx.

what do you guys think about the UltraLast CR123 Rechargeable Battery?

i can get two 700mah batteries and charger for $16


is 1400 mah total good with the R2 bulb or die within 20 min?

 

[Black Rose]

It's actually only 700 mAh total.

Voltage increases in serial configurations, capacity increases in parallel configurations.

Using 2xRCR123 in the G2 would be a serial configuration.

Can't comment on the Ultralast batteries.

EDIT: Is it a Nitrolon G2 or a G2 LED (Aluminum bezel)? A Nitrolon G2 won't handle the heat generated by the R2, which could eventually harm the R2 drop-in.

 

[Bullzeyebill]

Which R2 drop in are you getting from DX? What is the voltage range of the drop in? What is the voltage rating of the UltraLast rechargeable CR123?

Bill

 

[mojeb21]

i already heard news about running the light for very long due to the polymer.

but this light wont be used for more than 10 min at a time.. if that.

this is the bulb im getting
https://www.dealextreme.com/details.dx/sku.11836

the ultralast cr123 rechargeable say it is 700mah and 3v

 

[concept0]

For about $10 more, you can get 2 AW LiFePo4 batteries with charger. These are much higher quality batteries with a safe chemistry that will not vent (explode). Here's the link to the sales thread:

http://www.cpfmarketplace.com/mp/showthread.php?t=125353

They state a lower capacity (500mAh), but keep in mind that anything you get from DX or KD will have inflated stats...

 

[mdocod]

Why not use 3.7V LiCo cells? They will have ~double the stored energy. The 11836 is compatible with up to like 18V IIRC, no need to handicap yourself with LiFePO4 cells.

 

[mojeb21]

where do u buy 11836?

 

[Black Rose]

where do u buy 11836?

11836 is the SKU number of the R2 drop-in at Dealextreme

 

[mojeb21]

11836 is the SKU number of the R2 drop-in at Dealextreme

wow..thought he was talking about a battery..yea... its getting late for me. i should go to bed

so would a 18650 battery work well then?

i saw some on ebay ultrafire 3.7 v 2400mah with charger for like under20

 

[mdocod]

The 11836 requires ~5V cut-in voltage to operate at full output. On a single 18650 it starts at about 50% of normal full regulated output, and steadily declines through the discharge to about 25% of normal output. Has great runtime though when setup like this, and you'd be surprised how usefully bright a cree is at 0.5A. I have 2 lights setup like this on purpose.

 

[mojeb21]

so a 18650 is best?

 

[Black Rose]

so a 18650 is best?

They have the most capacity, but the issue is whether they will fit or not.

I suspect the largest cell size a G2 can take would be a 17670 cell.

 

[mdocod]

For the G2, assuming you are set on sticking with that body coupled to the 11836, you will basically be deciding on the following rechargeable options:

2xLiFePO4 RCR123s: ~30 minutes runtime at ~full output on an 11836. (~200 lumen)Followed by some dimming, at which point the cells will be suffering from over-discharge and will require user intervention to prevent loss of cycle life.

2x Protected LiCo 3.7V RCR123s: ~45-50 minutes runtime at full output (~200 lumen) on an 11836 followed by sudden shutdown (protection circuit terminating discharge to protect the cells).

1x protected LiCo 17670: ~3-4 hours of runtime, starting at ~100 lumen, diminishing to ~50 lumen through the majority of the runtime. The low drain rate towards the end of the discharge would have the potential to mildly over-discharge even a protected cell, so user should intervene and recharge before significant dimming occurs at the far end of the useful run.

2x voltage regulated protected LiCo cells (3.7V bucked to 3V cells): this is dumb, don't bother.