some more flashlight questions

[JHZR2]

Hello,

After the thread yesterday, Im a bit interested in getting some neat flashlights... maybe an AA quark...

But I have a couple questions pertaining to batteries for them. Really lithium ion batteries. I know Li-ion technology, and energy storage technologies in general, really well, but in this application, I would like to understand some aspects better.

So here it goes:

-I grasp protected vs unprotected li-ion cells. Li-ion batteries have a battery management system to protect from undervoltage/overcharge, sometimes short circuit/current, and also over/under temperature... Ive seen the effect of abused batteries without BMS - seems to me that there is no reason to buy unprotected cells. Is there?

-Some flashlights may offer "protection" built in for the cells. Certain chemistries, e.g. LiFePO4 have lower voltage ranges than standard LCO cathodes. Some of this stuff may be inconsistent... do flashlights often have cell protection?

-Ive seen a lot of CR123a lights. I dont see the purpose vs. a AA battery light - in terms of lonbgevity, as you only have ~500mAh. THat said, you have a higher voltage than a single AA. What are the benefits to 123 lights?

-Often Ive seen in places that sell li-ion batteries that they are not for flashlights. Is this because putting them somehow in place of a similar-size alkaline battery would go over design voltage for the light bulb? Otherwise, why do you often see "not for flashlights" on some batteries?

-are there any non-RCR123a lights that take lithium-ion batteries that are worthwhile?

-When looking to use a Li-ion battery in a light, is it merely a matter of matching the maximum bulb voltage, or do I need to make other considerations? For example, on the quark AA light, it takes 4.2V max - which an LiFePO4 will be below - so if I get a 14500 LiFePO4 cell, can I run it?

I may have others, but this is a good start. Likely Im looking at the quark lights - the AA and 123 types.

Thanks!

 

[eljefino]

I always thought the 123 lights descended from "tactical" units that were gun-mounted, tiny, and really bright for a short duration.

 

[XCELERATIONRULES]

I bought a few harbor freight led flash lights and gave them away to some friends.
They laughed until they needed them.
The led's are super bright,batteries last longer,and they are cheap.
If you lose them you won't feel bad,and they come with batteries.
I have plenty of mag lights I use at home,but I hate losing a $20 flash light.

 

[JHZR2]

Originally Posted By: eljefino
I always thought the 123 lights descended from "tactical" units that were gun-mounted, tiny, and really bright for a short duration.


short duration is right. Im actually disapointed by them at 450mAh, as well as 14500 cells, which are effectively AA batteries, also at 450mAh. Not that I have practical experience of it, just seems low...

While the 14500 is more or less a 3V battery, a 1.2V NiMH battery can hold 2000mAh, so in terms of total power, it is better. At high current, the li-ion may be better, but Im not looking for crazy things, just efficient, long0-life lights for various tasks...

 

[Carbon]

When searching for flashlights, look to the 18650 Li-ion cells. They are twice the length of the 123. Some lights with built-in regulators can take either 2 * 123 or one 18650 cell.

Nice size with more capacity.

 

[TooManyWheels]

Have you looked at CandlePower Forums? They are the BITOG of flashlights.

 

[Hoosier_Daddy]

when you look at the total energy a cell can give one good measurement is watts/hour. in some battery tests done at cpf, the leading AA alkaline(duracell ultra) gave 2.199 w/h compared to over 4 for the top 123. that is at at discharge of 0.5a, not much. up the rate to 1 amp and the AA falls to 1.27 w/h and the 123's still show in the 3's

 

[tmorris1]

Doesn't it have something to do with the flashlight also. It seems that cheap plastic lights kill batteries quick even if you don't use them. I have some nice metal gasket sealed lights (Maglight, etc) that seems to keep forever. They are good for keeping in the vehicle for emergencies. I have had good luck with Rayovac alkaline. They are cheaper than Energizer or Duracell and seem to last just as long.

 

[HyperJinx]

I have owned many many flashlights over the years as I need them and use them often. I have found that flashlight tech has made a huge leap in the past 10 years. It was forever before I actually let go of the old LARGE HEAVY flashlights but I finally did. If I needed a flashlight occuaptionally then I would probably buy an expensive one. My primary use is geared more toward a "task" light or "what was that noise" kinda light. Below are my 2 favorite flashlights:

1 Surefire 6P LED
Cost $100
brightness-80 lms
run time 3hrs
battery 123

2. Surefire g2
cost $35
Brightness 60 lms
runtime 1hr

 

[chevrofreak]

Originally Posted By: JHZR2
Hello,

After the thread yesterday, Im a bit interested in getting some neat flashlights... maybe an AA quark...

But I have a couple questions pertaining to batteries for them. Really lithium ion batteries. I know Li-ion technology, and energy storage technologies in general, really well, but in this application, I would like to understand some aspects better.

So here it goes:

-I grasp protected vs unprotected li-ion cells. Li-ion batteries have a battery management system to protect from undervoltage/overcharge, sometimes short circuit/current, and also over/under temperature... Ive seen the effect of abused batteries without BMS - seems to me that there is no reason to buy unprotected cells. Is there?

-Some flashlights may offer "protection" built in for the cells. Certain chemistries, e.g. LiFePO4 have lower voltage ranges than standard LCO cathodes. Some of this stuff may be inconsistent... do flashlights often have cell protection?

-Ive seen a lot of CR123a lights. I dont see the purpose vs. a AA battery light - in terms of lonbgevity, as you only have ~500mAh. THat said, you have a higher voltage than a single AA. What are the benefits to 123 lights?

-Often Ive seen in places that sell li-ion batteries that they are not for flashlights. Is this because putting them somehow in place of a similar-size alkaline battery would go over design voltage for the light bulb? Otherwise, why do you often see "not for flashlights" on some batteries?

-are there any non-RCR123a lights that take lithium-ion batteries that are worthwhile?

-When looking to use a Li-ion battery in a light, is it merely a matter of matching the maximum bulb voltage, or do I need to make other considerations? For example, on the quark AA light, it takes 4.2V max - which an LiFePO4 will be below - so if I get a 14500 LiFePO4 cell, can I run it?

I may have others, but this is a good start. Likely Im looking at the quark lights - the AA and 123 types.

Thanks!


You see "Not for flashlight use" on a lot of them, because a lot of flashlights can't handle the increased voltage. A pair of fresh CR123a's is about 6.6 volts with no load, and Li-Ion can be 8.4v with no load. The Li-Ion will sag less under load, which gives it yet more voltage over what the CR123a cells will have. This will blow an incandescent bulb instantly, and many LED lights that use resistors to cut power also will not handle the extra power. Most of them are designed to handle the extra voltage now, but ask the manufacturer about it.

And at this time, very few flashlights have built in low voltage cutoff. In a light with a current regulated a buck or boost circuit, they will often keep putting out light that is bright enough for you to not notice that it has begun dimming, and at the same time it can be draining the cell below the danger zone. If you overdischarge that Li-Ion cell, it just won't be the same again.

Now, for the lower capacity, you must also look at the voltage. The watt-hours is still pretty close to the Ni-MH cells.

The light below is a NiteCore Smart PD D10, which is a single AA light. It is capable of using a Li-Ion, as well as a Ni-MH.

The Duracell 2650mAh cell is one of the highest capacity you can get, but the 750mAh advertised capacity 14500 Li-Ion cell still runs about as long, and even at an increased output.

Standard lithium (not li-ion rechargeable) CR123a's have even more capacity. Most are around 1500mAh now.

This is the NiteCore EX10, which is basically the CR123a version of the D10 above.

Note how much longer the disposable CR123a ran than the Li-Ion rechargeable. CR123a cells do very well, and gain even more ground back when the power demand is decreased.

In some lights, the power demand is so high that the CR123a cell simply cannot supply enough power, and the Li-Ion will actually outperform it.

It should be noted that this light uses a boost circuit, but the voltage of the LED was high enough that the extra voltage of the Li-Ion cell did not overdrive it as would normally happen. In fact, the Medium mode was visibly dimmer than High mode, which usually doesn't happen. In many lights you completely loose the lower levels with a Li-Ion cell, because the circuit is not designed to decrease the voltage.

The below light is a Leatherman Serac S3, which is a slightly modified Fenix P1D CE. It has a lower voltage LED than the Fenix did, so on High, it is being overdriven.

Unlike the Fenix, the lower modes are completely indistinguishable until the cell voltage drops.

Be aware that the Quark MiNi lights are overdriven on high mode with a Li-Ion cell, and produce significant amounts of heat. That heat is not only very bad for the LED, but it can actually get hot enough to burn you. I have not tested the regular Quark lights, so I do not know whether they behave similarly, but I do not believe they do as they are actually from a different manufacturer than the MiNi models.

 

[JHZR2]

wow... thanks!

 

[ddrumman2004]

Wow! I didn't know there was so much to learn about a flashlight!
I have a Pelican SabreLite 2000 Submersible that my oldest son gave me as a gift. Works just great and the regular Duracells I have in the unit have been in there a long time.

My biggest problem with a flashlight is keeping it out of my 11 year old son's hands.

 

[Vikas]

Whatever you do, do NOT, I repeat do NOT visit Candlepowerforums

- Vikas

 

[eljefino]

the better flashlights at big lots (there's an oxymoron) claim 60-80 lumens and are <$15... play with one and you'll get hooked.

 

[JHZR2]

Originally Posted By: chevrofreak


You see "Not for flashlight use" on a lot of them, because a lot of flashlights can't handle the increased voltage. A pair of fresh CR123a's is about 6.6 volts with no load, and Li-Ion can be 8.4v with no load. The Li-Ion will sag less under load, which gives it yet more voltage over what the CR123a cells will have. This will blow an incandescent bulb instantly, and many LED lights that use resistors to cut power also will not handle the extra power. Most of them are designed to handle the extra voltage now, but ask the manufacturer about it.

And at this time, very few flashlights have built in low voltage cutoff. In a light with a current regulated a buck or boost circuit, they will often keep putting out light that is bright enough for you to not notice that it has begun dimming, and at the same time it can be draining the cell below the danger zone. If you overdischarge that Li-Ion cell, it just won't be the same again.



Thanks!

Can you recommend a maker of Li-ion cells (and a charger) for RCR123a size, 14500 AA size, and 18650 size?

have you done any studies on iron phosphate chemistries? How do they practically work out for lights?

ANY Li-ion batteries I buy WILL be protected. Ive seen Navy abuse testing of Li-ion batteries firsthand. I want the management on there. Any issues with this in regulated or unregulated lights?

Thanks again!

 

[drg]

I just stuck with the aa format because the 123 cost more and sometimes a little harder to find .I know that no matter where I'am at I can pick up some aa"s. I don't think the 14500 can be used in a quark aa .I did get some eneloops for rechargable batteries. I did buy the tactical tail cap for an extra 10.00 for my regular aa quark because it was so much easier for me to push.I highly recomend it for ease of use. It's not recessed in like the regular tailcap and does not change the fuction of the light.I tried to keep it simple and I'am very happy with what I bought.
Like I said before out of all my lights I prefer the Quark aa. It also has a 10yr warrenty and 4sevens has very good customer service.
You really should go over to candlepower forums, their very knowledgeable about lights and batterys and offer great advice.

 

[chevrofreak]

I like the AW brand cells, but the Eagletac cells are supposed to be good as well. The biggest problem I have is that there are so few decent Li-Ion chargers available. Some of them overcharge the cells, some undercharge. The Ultrafire WF-139/AW AW-139 charger are considered to be pretty good. The Pila IBC charger is probably one of the best, but is very expensive. Pila cells are also excellent, but very expensive. I am in need of a new Li-Ion charger myself as someone inserted a pair of cells into mine with reversed polarity and damaged the charger (it's one of the first RCR123 li-ion chargers made). The problem is that I'm having a hard time finding one that I consider worth buying.

There's a problem with the preotected cells, though, as most of the cells have a 2.5v cutoff, which goes back to the days when they were only used with incandescent lights. With an incandescent light, when the cell is nearly depleted the filament isn't burning as hot, and the resistance climbs. That makes it draw more power from the cell, and it will trigger the shutoff because the voltage sags below the 2.5v threshold, or the cell will detect it as a dead-short and cut the power. A single-cell light with a buck circuit will fall out of regulation (if it ever was in regulation) before the circuit cuts off. The light will continue to dim, and the protection circuit will not trigger until it is too late, and the cell has been overdischarged. You should not allow a Li-Ion cell to go below 2.9 volts, but because of the 2.5v cutoff and the continually declining draw, the voltage never sags below 2.5v

Like this Huntlight, which uses a buck circuit, the circuit needs a certain amount of voltage overhead above the LED voltage (most are around 3.5v at 700mA drive current) to regulate the power. The 4.2v open circuit voltage of a Li-Ion will often sag to below 3.8v at this current level, which is below the overhead required for regulation.

Some lights require even more overhead, and some have higher voltage LED's, which means the Li-Ion cell does not even start out at the same peak brightness.

The problem is not there in multi-cell lights, as the higher voltage will allow the light to remain in power regulation. As the cell voltage declines, current draw goes up, and eventually one of the cells will hit its cut off voltage, or current limit and simply shut down power.

I've used a few LiFePO4 cells, but I don't recommend them. None that I have seen use protection circuits, so they are very easy to overdischarge. The voltage is lower, so it works better with single cell boost circuit lights like the Fenix P1D and Leatherman Serac S3. The drawback is that their capacity is quite low compared to a standard Li-Ion cell. There are also so very few chargers specifically for them.

Here's a Fenix P2D with a RCR123 (Li-Ion CR123a, also sometimes called a 16340), a CR123a lithium primary, a 3v Li-Ion regulated cell (uses a linear voltage regulator) and a LiFePO4 cell. You can see that the LiFePO4 does not fare well. I terminated the test early because discharging these cells below 2v damages them.

 

[chevrofreak]

Originally Posted By: drg
I just stuck with the aa format because the 123 cost more and sometimes a little harder to find .I know that no matter where I'am at I can pick up some aa"s. I don't think the 14500 can be used in a quark aa .I did get some eneloops for rechargable batteries. I did buy the tactical tail cap for an extra 10.00 for my regular aa quark because it was so much easier for me to push.I highly recomend it for ease of use. It's not recessed in like the regular tailcap and does not change the fuction of the light.I tried to keep it simple and I'am very happy with what I bought.
Like I said before out of all my lights I prefer the Quark aa. It also has a 10yr warrenty and 4sevens has very good customer service.
You really should go over to candlepower forums, their very knowledgeable about lights and batterys and offer great advice.


I use a lot of AA lights because Ni-MH cells and good independent channel chargers are abundant and inexpensive, and the only real danger with Ni-MH is with gas venting due to a cell being reverse-charged in a multi-cell light, when one of the cells does not have the same charge state as the other.

That looks like this.

That was back when I did not have an independent channel charger, and one of the cells did not reach the same charge state as the other. During the test one of the cells vented and caused the rubber boot on the switch to blow up like a balloon.

 

[drg]

I've heard of that before but have never seen it.Something to be aware of for sure. Thanks for posting the picture of it. Darris