Choosing a "safe" RCR123A light

[travelinman]

Hi everyone...excuse a relative newby, but I'm having trouble navigating the many different manufacturer's descriptions.

Specifically I'm looking for a light that will operate a single RCR123A unprotected cell safely. OK, I thought, if it says it has "battery over discharge protection" on the description, it should be relatively safe. Or is it?

However, there's "current regulated circuit" which should afford some protection, or does it?

Then there's "input voltage 2.5 - 4.2V" which could mean that at 2.5V, it shuts off, or does it?

Then there are lights that blink on low battery voltage. These should indicate that you need to shut it off and plunk in a fresh cell. Is this enough protection for a careful user?

My lack of understanding of the circuits on many of these lights is showing, I know.

Any input on some guidelines would be appreciated bearing in mind I'm not a complete idiot when it comes to electronics and safety.

 

[Oddjob]

The Ra lights are good for this. When I am using it and it steps down in brightness because it senses the battery is low, I just put in a fresh cell. It steps down when it senses there is not enough power left in the cell to sustain the level you were just using and then blinks every minute to remind you to change to an even lower level or change the battery. Despite this feature Ra still suggests the use of protected cells. Novatac lights also do this since they are based on the HDS EDC design.

The Liteflux LF3XT has a battery voltage detection feature where you click it five times and it tells you roughly the voltage of your battery. For example, 3.9 volts would be 3 slower flashes followed by 9 quicker flashes. I generally change batteries if it shows less than 4 volts.

With my other lights I just swap out the cells if I think I have used them a lot. I find I generally catch the cells before they go below 3.8 volts. I certainly do not rely on the protection circuit as this is bad for the cell in the long run.

Even if you use lights that have these safeties built into them I still recommend is a decent charger like the Pila IBC charger, good protected cells such AW cells which are available on the CPF marketplace and the use of a digital multimetre to determine the state of a cell's discharge.

 

[Derek Dean]

Howdy travelinman,
Just in case you haven't seen these.... you might be interested in both of these links:
http://www.batteryuniversity.com/
http://www.candlepowerforums.com/vb/showthread.php?t=201375

I agree with Oddjob, even with an excellent light like the RA, the LiteFlux LF3XT, or the NovaTac EDC lights, you will want a good charger and high quality PROTECTED cells.

I see no point in using inexpensive unprotected lithium-ion cells. Let's say there is a problem with your charger (it happens) ...... an unprotected cell offers no protection from overcharging. Even WITH protected cells AND a good charger, it is most highly recommended that you not leave lithium-ion cells charging unattended. Many folks have a special charging area with a fire resistant surface for the charger....... just in case.

Do yourself a favor, go to CPF member AW's sales thread in the CPF Marketplace dealer's area and get some high quality protected cells.

 

[buickid]

The NovaTac EDC 120T/E/P lights have an option that you set if you're using RCRs. On RCRs, it will drop the brightness level as the battery gets lower, and when it gets to the lowest level, and battery voltage is too low (~3V), it will start blinking. At this point, you should recharge the battery, but the light will continue blinking and sacrifice the battery, because it assumes that you are in an emergency situation where the battery no longer matters. (Read: The SHTF big time)
If you set it to use CRs, then it probably does something like readjust the brightness step-down curve, and alter the cut-off voltage to something lower. It says to make sure its set to use RCRs if you're using RCRs. Whenever you change battery types, its quite simple to set it. You insert a new FULLY CHARGED/FRESH cell, screw the tail on fully, turn the light on, unscrew cap just enough so light turns off, screw it fully on again, and hold down the button until the light turns bright, then dim. Then you release. Sounds complicated, but it takes about ten seconds, and the manual explains it better. :twothumbs

Here, quoted from the 85P/120P manual. Copyright 2007 NovaTac, Inc.
"1. Turn the light on.
2. Unscrew the battery case until the light turns off.
3. Screw the battery case back together; there will be one second of dim light.
4. During the one second of dim light, press and hold the button.
5. You will see five seconds of bright light, followed by dim light.
6. Release the button when the light goes dim.
7. The Battery-Detect-Reset is complete."