Newbie question about CR123 operation

[highseas]

Hi, I'm new to this hobby and have never had a flashlight running CR123s. I bought a Solarforce L2 recently, and am starting to read stuff about CR123 and some potential problems. Please enlighten me if you can:

1. Is there any problem at all in just keeping the flashlight turned on? I've read stuff on this forum about "overdischarge" that could damage the cells or the flashlight, as in turning it on for longer than 30 minutes?? I never had to contend with this problem when using AA, AAA. Is this real? I'm most worried about this problem. It would kind of be self-defeating to have a flashlight that I can't keep on for more than 30 minutes or an hour, if true. And is this only a problem for unprotected cells?

2. Is it recommended that one uses "protected" CR123 primaries? Is this a problem related to the discharge rate?

3. Could you point to any review/comparison of various brands of CR123 primaries or rechargeables? (I'm looking for a long runtime primarily, some sacrifices in brightness is ok).

4. What are the advantages of CR123s over AA, AAA (which are cheaper and more widely available)? From what I've read, it seems to come down to longer shelf live.

Thank you very much!

 

[greenLED]

:welcome: highseas

:thinking: It seems to me that you might be confusing rechargeable li-ion batteries with "primary" batteries (non-rechargeable)...? I mention this because of your references to protected vs. unprotected cells.

1. In general terms, the short answer is "no". However, if you're using a high-powered incandescent light, and your 123 cells are at different levels of charge (for whatever reason), that may lead to "venting with flames" as one of the cells may "reverse charge" (which they don't like at all).

2. This is where I started thinking you might be confused between primaries and rechargeable batts. If you decide to use rechargeables, I strongly recommend you use protected cells - that way you don't have to worry about overdischarging (which harms the cells), overcharging (which damages cells and may lead to explosions), or shorts (which lead to ).

3. Look for a sticky thread, started by SilverFox, in the Batteries and electronics section. That's the Bible of 123's. There are similar threads for rechargeables.

4. Other than longer shelf life, you also have better performance at critical temperatures, higher voltages.

 

[highseas]

Thanks, GreenLED. In regard to #1, if I have a LED bulb (CREE R2) then there is no problem then?

 

[Oddjob]

1. Overdischarge refers to rechargeable CR123 batteries (RCR123's). These come in protected or unprotected. Protected cells have a circuit that stop the battery from discharging past a certain voltage. Unprotected cells do not have this so they can be run down to voltages low enough to damage the cell. You can run regular CR123's also called primary cells for extended periods but you have to consider what kind of light you are using it in. If you run a light that has no heatsinking for extended periods of time you will damge the LED.

2. Protected cells are recommended for lights that do not have low voltage proection built in to the circuitry of the light.

3. This thread is long but useful: http://www.candlepowerforums.com/vb/showthread.php?t=67078

4. CR123's provide more voltage in a smaller form factor at the expense of runtime. CR123 are 3 volts which is the same as 2 AA's so for the added runtime and same brightness you get a larger light. Nowadays with the new generation of emitters, single AA lights are emitting brightness levels similar to single CR123 lights. AA NiMH are better to use than alkalines. CR123 and lithium in general are better for shelf life and extreme weather performance.