# CR123a vs RCR123a



## willstilson (Oct 29, 2008)

Sorry if this is a new question but I'm still new to rechargeable LiIons. I just got a pair of RCR123a from AW. Both batteries test at about 3.96v on my dmm. I immediately noticed that my Fenix T1 appeared dimmer when, I threw them in, compared to the CR123a's I had in there before from battery station. I did a current draw test at the tail cap. With the CR123a's I got around .795A and with the RCR123a's I got around .595A. I'm just wondering if this is normal or not. Again sorry if this has been covered but I did not find the answer in my searching.


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## moldyoldy (Nov 1, 2008)

Hi willstilson, sorry for the delay in response - saw this question before, but was not logged in at the time. 

The T1 has a similar circuit to the P3D and other 2x123 Fenix lights. the drive circuitry draws a lower current from the higher voltage RCR123 cells than from the lower voltage CR123 cells. Some lights have a buck/boost circuit that will compensate for quite a range of battery voltage and thereby resulting in stable light output. The same current draw difference between high voltage and low voltage (x)CR123 cells has been observed on any of the P3D-Q5 units or both of T1s that passed thru my possession. 

FWIW, fresh CR123 cells operate somewhere slightly above 3.0v under load. The normal RCR123 cell from AW and others is nominally 3.7v under load. There are also RCR123 cells that are listed as 3.0v that utilize some variant of a simple circuit or resistor to drop the voltage under load to the range of a good CR123 cell for compatibility. Most of the time the voltage dropping method is a good guess. Also, for protected RCR123 cells, there are cases where the protection circuitry is not able to handle the current draw.


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## 300winmag (Nov 2, 2008)

So if I put protected AW RCR123's in my TK11 will it also be dimmer then using standard CR123's?


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## moldyoldy (Nov 2, 2008)

300winmag said:


> So if I put protected AW RCR123's in my TK11 will it also be dimmer then using standard CR123's?


. 

indeterminate results. It depends on the ability of either cell to supply the load current and still maintain a good output voltage all relative to the regulation circuitry of the light. Some rechargeables drop their output voltage under heavy load more than non-rechargeables. For example, look at the testing that Firefox did on various CR123 cells - obvious differences in output voltages under the same load between brands. Would those differences be observable in the output of a flashlight? depends. again, look at some of the tests of lights and the specified cells - obvious differences in output between cells. 

For that matter, I have never had my hands on a TK11 - therefore unaware of the specifics of that device. 

Here is an example of a battery ageing problem: I have an Energizer NiMh AA cell of 2500mah capacity - quite old, but still tests in at around 2200mah on my BC-900. I also have a Maha Imedion AA cell of 2100mah listed capacity - quite new, have not run a recent capacity test. I also have a couple L1D-Q5 units. The L1D-Q5 lists 107 lumens on "high" and 120 lumens on "turbo". Many users have commented that they cannot see the difference. When I insert the Energizer cell, I cannot see a difference between those two modes. When I insert the Imedion cell, the difference is obvious. That test provides consistent and repeatable results between the different L1D-Q5 units as well.


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## moldyoldy (Nov 2, 2008)

actually I recommend that you check in to the "sticky" at the top of the forum for a wealth of test information on batteries and cells. Saved me a lot of time trying to figure out "why" with some of my own lights and problems!

Also, do a search for the TK11 and some runtime test results. If you do not find what you want in the CandlePowerForums, then try:

http://www.light-reviews.com/reviews.html

The TK11 is listed there with run-time graphs of output/time


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## moldyoldy (Nov 2, 2008)

fwiw, I just did a current draw on my P3D-Q5 on turbo:

2x 3.7v RCR123 cells: .50 amps
2x 3v RCR123 cells: .66 amps
2x Energizer CR123 cells: .68 amps

those numbers correlate rather well with the voltages under load. the higher the voltage under load, the lower the current drawn.

Also, for nearly all new or newly received rechargeable cells, it would be good to run them thru a couple charge/discharge/charge cycles before passing any judgement on their capacity or characteristics under load.


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## willstilson (Nov 2, 2008)

Thanks for the response. I figured that the device was just drawing less current do to higher voltage but that was conflicting since I believed that the flashlight had some sort of regulation that would prevent that. It all makes sense now.


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## matrixshaman (Nov 2, 2008)

You should probably charge both AW cells first to around 4.15 to 4.2 volts so they will be fully charged before testing brightness. At 3.96 volts they are not fully charged. In most cases lights will be brighter on rechargeables then primaries but not all drivers work the same and not all setups will work out this way.


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