What is the resting and float voltage of 3.0V RCR123

[Learjet]

Got some 3.0V RCR123 batteries and charger today. Want to double check they are at the correct float and rest voltage with a DMM.

Are they 0.7V less than regular 3.7V Li-ion (float 4.2-0.7=3.5V) or something different?

 

[max52]

I have Tenergy 3.0V R123a, and Powerizer 3.0V R123A. There is not much difference between the open voltage of the 3.0V R123A and the traditional 3.7 volt R123A. The Tenergy measures around 3.9, and the 3.7 measures around 4.1X. The Powerizer voltage drops to around 3.2 under load. Multimeters are not much use with the 3.0V R123A.

 

[mdocod]

what you have there is a regular li-ion cell, shrunk down even smaller than a regular RCR123, to make room for a voltage regulator. So the cell capacity will actually be less than a regular RCR123 by a fair bit to begin with, and then the regulator will chew up another ~20% of the juice and turn it into heat, right next to a cell that doesn't get along with heat very well.

 

[Learjet]

I see, thanks for the replies. Looks like these cells arn't much good then for flashlight applications.

Looks like your also correct of the capacity mdocod. I'm only getting 300mah back into these cells after a cycle, although I'm not discharging them below 3.0V.

I gather the 3.6V cells are of similar non usefulness? I'll have to get some protected 3.7's next time.

 

[Lips]

I believe mine sit at around 3.37 to 3.4 v.

 

[mdocod]

3.6 and 3.7V are (usually) just labeling differences, they are usually all the same chemistry and come off a charger at 4.200V when charged properly, and are finished around 3.2V.

Ideally, setting up a light that can use either 1 3.7V cell, or 2 3.7V cells (so, either a 3.7V design, or a "9V" design works good.).. there are many ways to setup configurations that run 3.7V cells... what are you using yours in? In some situations, there isn't any other good way to go rechargable, like circuits that demand a ~3V or ~6V input. just no way around it.

hope that helps.

 

[Learjet]

I just intended to use them in the Fenix P2D and P3D. I got the 3.0V ones as the 3.7V type don't allow switching of all modes. I'm also a little scared to blow the emitter on the P2D with a 3.7V cell, although I haven't read of anyone doing that yet. Unfortunately it seems these lights only work as designed on primary cells.

 

[mdocod]

I believe the P2D would have the same problem that people running 14500s in L1D experience like you say (loss of low mode, apparently a lot of overdrive, potential for overheating.).

However, I'm betting the P3D, which is designed for 6V, would probably work pretty well on a 17670 (if it will fit in the tube, if not a 14670). That would be a single 3.7V cell that fills the space of the 2 CR123s. Only worry is that it might not regulate on high very well. (probably a buck regulator only)

 

[Learjet]

Yeah I have read of problems with the P3D and certain cells not fitting inside too well. I'll have to find those threads again. In fact I think many 3.7V Li-ion cells didn't fit either.

 

[mdocod]

the 14670 might be the way to go in the P3D then. It's skinnier than a CR123, same length as 2 CR123s back to back though. Only get ~1100mah, but it shouldn't have any fitment issues. Would be nice to know before trying if the high mode works though.

 

[Learjet]

I'm going to change my opinion of these 3.0V cells. I haven't been discharging them low enough to get a decent idea of capacity.

With intermittent use in the P2D I'm getting a good 27 minutes run time. That's close to half what I get on primaries.

The capacity of these 3.0V cells must be above 600mah to do that. In which case they will be useful afterall.

 

[Lips]

These are at lighthound.com (listed at 700mah but they send 1000mah version). The ultrafire charger sold there has 3v and 3.6 setting.


They are working great in my gladius to get rid of the blink...

As mdocod said the lith ion is set to 4.2 but these are working nicely...


Cheers

.

 

[Learjet]

I have similar ones, with 1000mah on them. Got a cheap charger with them so understand that I have to remove them as soon as the green light comes on.

I have a better charger for 3.6V and over. It's a swallow and cuts off without trickle at 100mah input at float.

 

[barkingmad]

Not sure I would like charging Li-ion cells with a 'cheap' charger... :candle:

 

[Learjet]

Yeah I'll have to get a better one when I have the $.

It measures 5ma trickle after charge. Not a lot but not something that should be left on either.