Specific questions about 3.0V RCR123A

[LiteShow]

Hi Everyone,

I recently purchased a P1D Q5 and currently run on primaries. Seaching the forums about rechargeables, it seems that the 3.0V RCR123A is the only way to get all modes - so I have narrowed down to the http://www.batteryjunction.com/4parc390reli.html Tenergy RCR123A 3.0V 900mAh kit.

I understand that these cells are protected. So with the smaller capacity of only 900mAh, my main concern is that the protection circuit cuts in before the battery is fully drained - thus we have even a shorter runtime. When used in a Fenix P1D or P2D Q5 single cell light, how's the runtime compared to primaries??

The turbo mode consumes about 1.4 amps using primaries. With the rechargeables, will the high current cause the voltage to drop even quicker to the cut-off protection voltage?

So what kind of results are you guys getting?

Dennis

 

[jsr]

I don't have a P2D or the Tenergies, but I will say that the 900mAh is a padded capacity rating. It is likely only about 600-650mAh (virtually all protected 3V R123As are about 600mAh). This seems to be the type where it's a 3.6V cell with a circuit that not only protects, but also drops the voltage, which average 600mAh. The type that are 3V by chemistry (no internal circuit to drop voltage, slightly different chemistry) have even lower capacities (typically around 300-500mAh). To get an estimate of runtime, take the 1.4A draw and divide it into 600mAh and you'll get a rough estimate of continuous runtime on high. Yes, it's not very long.

 

[mdocod]

Fenix CR123 lights are lousy for people who want rechargeable options. I'm sure you probably did a little research and read so many glorious reviews about it before buying it, You really have anyone who wrote anything about it that didn't mention that it is only good for people who are interested in using primary CR123s and has no good rechargeable options available to blame at this point in time. I have been HOUNDING CPF in every possible place to STOP recommending these fenix CR123 lights like they are the god of lights, they are AWESOME for people who run primary cells, but if you want rechargeable, these lights SUCK! An L1D CE or L2D CE would have been much smarter (NIMH AAs are cheaper, safer, and have better energy than current RCR123s)

If it is drawing 1.4A, then keep in mind that there aren't any 3.0V (voltage regulated) cells that are designed to handle that kind of current, most are rated for no more than about 1-2C. (in this case the voltage regulator in the cell might be good for up to around 1 amp, but keep in mind that the cell itself is nowhere near that 900mAH rated capacity, best case scenario you MIGHT get 600mA or about 20 minutes runtime IF the regulator doesn't burn up from heat, or the protection circuitry doesn't shut it down before hand.

I would use the P1D with primary cells for emergencies and special occasions, and get another light that takes an 18650 size li-ion cell to use as a rechargeable every day use type light.

 

[SilverFox]

Hello Dennis,

Welcome to CPF.

In addition to what Mdocod mentioned, let me add that you are correct in your understanding that higher loads will drop the voltage and give you less usable capacity.

Also, keep in mind that when you push Li-Ion cells to the limit, cycle life drops off. Cycle life is rated using a 5 hour discharge test. When you discharge at higher loads, some of the energy turns to heat and you end up with lower usable capacity.

At high loads, you will get better cycle life if you limit your use to 70 - 80% of the available capacity at that load. If you run the cell all the way down every time, you may only get 10 - 50 cycles from it.

Let's take a realistic look at the numbers. You have a cell that probably starts out at around 500 mAh. You are pushing it at just over 2C, so, when new, you can expect around 21 minutes run time if you completely drain the cell. If you limit your discharge to 80%, your run time drops to around 17 minutes.

I prefer to use lights that give me around an hour on bright. If I were considering this light/battery combination, I would have to carry 3 extra charged cells to meet my expectations.

Tom

 

[ltiu]

Fenix CR123 lights are lousy for people who want rechargeable options.

NOT ALL FENIX CR123 lights are lousy for people who want rechargeables options.

The P3D is perfect for rechargeables. I have a P3D Q5 and I use rechargeable Li-on 3.7 volt AW RCR123A on them just fine.

 

[mdocod]

NOT ALL FENIX CR123 lights are lousy for people who want rechargeables options.

The P3D is perfect for rechargeables. I have a P3D Q5 and I use rechargeable Li-on 3.7 volt AW RCR123A on them just fine.

An 18650 powered light of similar size will run 2-3X longer at the same output, users of the P3D report about 45 minutes runtime on turbo with RCR123s, The high efficiency emitter is squandered on a lower power density rechargeable option. A 2xAA light has more power (watt hours) available than a 2xRCR123 setup.

For a daily user who doesn't need much runtime who can recharge often, yes, it probably is "just fine." But it's still giving up a lot. I think, maybe it's just me,. ...

I guess I'm used to the concept of alkaline powered lights, that when you upgrade them to good rechargeable NIMH cells, IMPROVEs performance and runtime. In the case of the P3D, going rechargeable means giving up something.

 

[Curious_character]

NOT ALL FENIX CR123 lights are lousy for people who want rechargeables options.

The P3D is perfect for rechargeables. I have a P3D Q5 and I use rechargeable Li-on 3.7 volt AW RCR123A on them just fine.

And I get all modes on my P1D and P2D with a 3.0 volt AW LiFePO4 cell.

c_c

 

[Alan B]

...

I guess I'm used to the concept of alkaline powered lights, that when you upgrade them to good rechargeable NIMH cells, IMPROVEs performance and runtime. In the case of the P3D, going rechargeable means giving up something.

This comparison is not exactly fair.

In an AA light, going from lithium primaries to any other battery type gives up a lot of performance.

With the CR123A battery size, we don't have the alkaline or nimh options, so we only see the lithium primary to lithium rechargeable options.

In my P3D, going from primary to 3.7V rechargeables only reduced the output on low. The runtime on these cells is more than I use in a few days, and they can be swapped for recharged cells for guilt-free lumens.

I think the best choice for the P1D though is to either use the LiFePO4 cells, or swap to an L1D body tube and use NiMH AA. The LiFePO4 cells are inherently much safer than either lithium primary or li-ion 3.7V cells. Their 3.2V makes the light work normally, aside from the low setting being medium for a few minutes when the cells come fresh off the charger.

-- Alan

 

[LiteShow]

Thanks everyone for the input about the Cr123s..

Alan B & curious_character, you guys mention that you use LiFEPO4 batteries. The ones I have seen so far are unprotected cells. How would you know when to stop using your flashlight so it does discharge too low?

In a different thread, I was asking about using an AA body for P1D and realize they don't make one. The AA body is only for a P2D/L2D. So I emailed Fenix (the manufacturer) and suggested an AA body for the P1D. The service person says she will forward the idea to management for consideration.

 

[mdocod]

The ones I have seen so far are unprotected cells. How would you know when to stop using your flashlight so it does discharge too low?

if you decide to go with LiFeP04 cells, try not to worry too much about over-discharging them, rather, make it part of your routine to charge them frequently to prevent it. If you do happen to need to run the light for an extended time some night, shut it off if it dims noticeably and you should be fine,. LiFeP04 chemistry seems to be pretty resilient and will "bounce back" more like NIMH. Over-discharging isn't ideal, but isn't the end of the world.

 

[Curious_character]

I second mdocod's comments. (Edit) Both the P1D and P2D maintain full brightness, even in turbo mode, when the cell voltage is well below the recommended minimum of 2.0 volts. So you should charge it frequently enough to keep it from overdischarging.(/Edit) I've discharged them well below that while testing for run time, and found no loss in capacity as a result. The worst that's happened is that I've had to put a cell into a 3.7 volt cell charger for a few seconds to kick the voltage high enough for the proper charger to begin charging it. These are really nice and forgiving cells, if you can tolerate the somewhat lower capacity than other cells of the same size.

c_c

 

[Darkpower]

Hi Everyone,

I recently purchased a P1D Q5 and currently run on primaries. Seaching the forums about rechargeables, it seems that the 3.0V RCR123A is the only way to get all modes - so I have narrowed down to the http://www.batteryjunction.com/4parc390reli.html Tenergy RCR123A 3.0V 900mAh kit.

I understand that these cells are protected. So with the smaller capacity of only 900mAh, my main concern is that the protection circuit cuts in before the battery is fully drained - thus we have even a shorter runtime. When used in a Fenix P1D or P2D Q5 single cell light, how's the runtime compared to primaries??

The turbo mode consumes about 1.4 amps using primaries. With the rechargeables, will the high current cause the voltage to drop even quicker to the cut-off protection voltage?

So what kind of results are you guys getting?

Dennis

I bought the Tenergy 900 mA RCR123 found on this page (link) and found them to be very satisfactory. I use them in my FENIX P1D Q5, P2D, P3D Rebel, Fenix T1 and Surefire L2. There are just a few issues. For one in the Surefire the battery tube is very tight and I had to remove the Tenergy label skin which tears if you force it in. In the Fenix they fix perfectly. They run about 1/3 the run time of a primary. For example I get 24 mins on turbo with the P2D. But I get well over 8 hrs on low-low. The other two issues are minor. In the T1, the protection circuit sometimes trips when turning on the T1 after a prolong inactive period. When switched on, the light flickers once and shuts down, then the clicky has to be hit a couple of times, before the lamp kicks in and stays on. My assumption is there is a outrush of current to power up the T1 which exceeds the protection circuit discharge current limiting specs especially since there are two of these protected cells in series. The flashlight circuit may have a large cap that causes a large inrush of current on turn on. Then with the P3D Rebel, the flashlight will quit in turbo mode after about 16 minutes without any "low battery" indication which is a strobe (LED Flickers at about 30 Hz) on that specific unit. The reason is that there are two protected cells in series and when the voltage of one of them drops below spec, the "discharge" protection circuit kicks shutting off outgoing current before the flashlight electronics can kick in.

All the batteries work real well on the low settings, and when in turbo, I try to limit their use to intermitten use of no more than 10 minutes at a time.

Prior to buying rechargeable Li-ion Rcr123 I limited my use of these crc123 flashlights because I hated the idea of burning $2 and $4 worth of batteries in an hour or so. I also never really knew what "state" of discharge the primary was in...whether I had 10 minutes or 40 minutes worth of use, and I hated erroding away the charge in primaries by using it for a few minutes at a time. I have this thing about keeping primaries fresh and fully charged for emergencies.

The result was that I rarely used those lights. But with the rechargeables rcr123, I use those lights nearly every day now. Generally I use them for about 10 minutes once or twice a night (taking out the garbage, checking the well water system, going in the tool shed, etc). I top-off the batteries every few days and so I know exactly how much run time I have and if I need a freshly charged set of batteries...I can top it off and have guilt-free lumens at my disposal. Anyhow I really recommend these Li-ion RCR123. I bought about 14 of these cells which I use in rotation, and they are all good, and I haven't noticed any capacity loss in the 5 months or so that I have been using them. Plus I found they were relatively cheap.

 

[LiteShow]

Again, thanks for all your helpful and useful replies. I have made up my mind

After much consideration and with safety in mind, I've decided to stay away from Li-ions. Granted, Li-ions are everywhere and chances of fire or exploding is rare, but I just feel more comfortable knowing that my EDC isn't going to go in my pants!


So I ordered LiFePO4 cells through AW this morning. After reading about the run-times other CPFers have with their P1D and P2D using LiFEPo4, I'll say I am very comfortable with these cells. For extended runtimes, I just need to carry a couple of spares - otherwise, my usage is probably like a few minutes a day, which probably translates to replacing single cell P1D every week or so.

 

[Alan B]

Again, thanks for all your helpful and useful replies. I have made up my mind

After much consideration and with safety in mind, I've decided to stay away from Li-ions. Granted, Li-ions are everywhere and chances of fire or exploding is rare, but I just feel more comfortable knowing that my EDC isn't going to go in my pants!


So I ordered LiFePO4 cells through AW this morning. After reading about the run-times other CPFers have with their P1D and P2D using LiFEPo4, I'll say I am very comfortable with these cells. For extended runtimes, I just need to carry a couple of spares - otherwise, my usage is probably like a few minutes a day, which probably translates to replacing single cell P1D every week or so.

Your choice sounds reasonable to me. That is about what I am doing as well.

The LiFePO4 are fairly hard to damage, as others have mentioned. They usually recover from the rare deep discharge, and some chargers even have a recovery cycle for this.

My philosophy has been to charge way more often than required, and if I ruin a cell (has not happened yet, but it will), I will just toss it and move on. Unless I make an overdischarge mistake often, I will still save a lot of money over using primaries, and enjoy a lot of guilt-free lumens.

If I get into a situation where I need light for a long time (such as a real emergency) I plan to switch to primaries at the first opportunity, and not even wait to discharge the rechargeables.

Incidentally, LiFePO4 are actually a member of the lithium-ion type of which there are many chemistries. So you have chosen Li-ions, just a particular chemistry that is safer than the more common varieties.

-- Alan

 

[Curious_character]

I second mdocod's comments. The light gets extremely dim by the time the cell voltage gets to its recommended minimum, so there's no way you'd accidentally overdischarge the cell if you're using the light. And I've discharged them well below that while testing for run time, and found no loss in capacity as a result. The worst that's happened is that I've had to put a cell into a 3.7 volt cell charger for a few seconds to kick the voltage high enough for the proper charger to begin charging it. These are really nice and forgiving cells, if you can tolerate the somewhat lower capacity than other cells of the same size.

c_c

I'm sorry, what I posted is not true. I had my lights confused -- the P1D runs at full brightness even in turbo mode even well below the minimum recommended LiFePO4 voltage of 2.0 volts. And the P2D head is the same as the L1D (one AA) and L2D (two AA), so it will also run at full brightness at low voltages. If you use an LiFePO4 cell in either the P1D or P2D, you need to make sure you charge it often enough that it won't overdischarge. As I said, I've run them considerably below 2.0 volts without any immediate loss in capacity, but there might be some lifetime reduction or other effect, so it probably isn't a good idea.

I apologize for the bum steer -- I've edited my earlier posting.

c_c

 

[Alan B]

I'm sorry, what I posted is not true. I had my lights confused -- the P1D runs at full brightness even in turbo mode even well below the minimum recommended LiFePO4 voltage of 2.0 volts. And the P2D head is the same as the L1D (one AA) and L2D (two AA), so it will also run at full brightness at low voltages. If you use an LiFePO4 cell in either the P1D or P2D, you need to make sure you charge it often enough that it won't overdischarge. As I said, I've run them considerably below 2.0 volts without any immediate loss in capacity, but there might be some lifetime reduction or other effect, so it probably isn't a good idea.

I apologize for the bum steer -- I've edited my earlier posting.

c_c

Thanks for the correction. I will note that the 1xAA L1D turbo is less bright than the 3V setups (either P2D or L2D). The lower settings are not different. So the only way one could judge battery voltage low at 1.5V would be by looking at turbo and noting the difference between 180 and 120 emitter lumens (Fenix spec for Q5 head). This is not a lot of difference to spot. There would be no difference on the lower settings.

If in doubt, swap it with a charged one and recharge it.

I just charge once a week or so, and if I'm going to use it a lot I charge it more often or change to primaries, or the 1xAA P1D body and use a NiMH.

-- Alan

 

[LiteShow]

Thanks for your comments. I've replied your PM, curious_character.

Once the LiFePo4 comes in, I will try them out. I think in spite of it's nature, my usage of the P1D as an EDC will not cause problems with the cells. A few minutes a day with frequent use on a freshly charged LiFePo4 and then swap batteries once a week will be my typical usage.

If I plan to use longer, I will just have to remember putting in freshly charged cells and swapping them ever so often. Again not a big deal for me.

Correct me if I am wrong, the electronics in the P1D is both voltage and current dependent? I know my P1D head works well with a 1.2volt Nimh - but the Nimh is pumping out like 1.5A. As voltage of the cell drops and current increases, they comes to a point where there is insufficient capacity in the cell, and therefore as the voltage drops the current doesn't increase but drops with it. I noticed that with the Primaries (voltage still above 2.2volts but current way below 500mah) and the dimming effect was obvious - obvious enough to know that high and turbo are the same intensity and that high doesn't feel like high anymore. Are you guys saying that the LiFeP04 doesn't behave like that?

 

[mdocod]

The way you described the behavior of the P1D there is almost perfectly accurate:

Yes, as the input voltage drops, the regulation tries to ramp up the current to maintain power to the LED, so in some cases, lower voltage can result in MORE current flowing into the regulator,.. Now... if you took an OPEN CIRCUIT measurement of a CR123 primary and it was 2.2V, then I can tell you it was VERY VERY dead... the reason only 500mA is flowing from the cell to the P1D regulator, is that when you complete the circuit that load is dragging the voltage down probably somewhere in the ballpark of 1V or LESS.

The reason I don't think you are going to have a problem is that as long as the resting voltage of the LiFeP04 cell "bounces back" to 2+V and you get it on a charger within a reasonable time, the cell really shouldn't suffer much damage. Yes the P1D head is probably capable of dragging that thing loaded down to about 0.9V.... but I suspect you will notice some dimming on the higher modes long before that. LiFeP04 is so much more robust than the LiCoO2, and since they are only a couple bucks a piece even if you only get a hundred cycles instead of a thousand cycles out of them they will more than pay for themselves. From what I have heard about LiFeP04 cells, they behave a lot more like NIMH chemistry than Li-Ion as far as being tolerant to abuse.

 

[matrixshaman]

I'll just say I've tried several different '3.0' volt RCR's in Fenix lights and you still can barely tell the difference between high and low. This is the reason I've quit buying Fenix and refuse to buy more until they focus on this problem and correct it. Other lights I have don't do this so I know Fenix can fix it but they seem so busy cranking out new models of every little change in LED bin or other things they still haven't bothered to fix what I see as a big problem. I've gone to almost strictly rechargeable lights and that seems to be the way many lights are going now but Fenix seems to continue to ignore this trend. I like Fenix lights but I'm in boycott mode for now. Get 'green' Fenix or lose. :nana:

 

[marrandy]

Thanks for your comments. I've replied your PM, curious_character.

Once the LiFePo4 comes in, I will try them out.

And...

How are they ?

What brand ?

Where did you get them from ?