Battery and charger experts

[fatboy]

Hi all!

I'm a noob around here, so a little background first...

Recently I wanted a photon gun in a small package, packed with power, economical and gotta be blinding.

After lurking here, comparing the Cree and Rebels, I decided on a fenix rebel, CR123 light, 175 Lumens, 2XAA body/tails available, which will come quick.

So now, here's the question....

I've got an Electricfly Triton charger.

I charge Ni-cads, Ni-mH in the AA, C, flavors in 2, 4 and 8 cell configs, pretty straight forward stuff.

The R/C aircraft planes and helicopters use 2 or 3 cell li-pos and the charger increments of 3.6, 3.7, 7.2, 7.4, 10.8, 11.1. Each Li-po is what, 3.2V?

They claim this charger will also charge Li-ions.

Looking at a CR123, this is a 3.0V (lithium) battery.

Can I get a pair of AA Li-ions or CR123 rechargable Li-ions to use with this flashlight/charger? Do they exist?

Just a 20,000 foot question about batteries and charging , a bit confusing right now.

Thanks for looking!

 

[coppertrail]

Unless they upped the output voltage on the Rebel L2D, you can't use 14500 Li-Ion cells with the light. I recommend either eneloop or Powerex 2700 mAh cells. You can use energizer lithium primaries, but for cost reasons, I'd stick with one of the NiMH cells listed above.

Regarding your charger, is it designed for 3.0, 3.6, and 3.7V Li-Ion cells? If so, you should be able to charge just about any RCR-123A cell. If it only accomodates 3.0V RCR cells, don't charge 3.6 or 3.7V cells in the charger.

 

[fatboy]

What is a 14500 Li-Ion cell? Higher voltage?

The mfg couldn't help much, hence the reason for my post.

I listed the output increments, and again the reason for my post.

Rechargeable Li-Ion cell (do they exist?) rated at 3V need to be charged at what voltage? What is "RCR"? Rechargeable CR perhaps?

Guess the end result may be to use Ni-Mh in my case.

Thanks for the input!

 

[coppertrail]

OK, sorry, I see you bought a CR123A rebel, you threw me off with that 2AA tube

What is the exact model of the Fenix Rebel light that you purchase?

 

[SilverFox]

Hello Fatboy,

Welcome to CPF.

In general, Li-Po cells have a nominal voltage of 3.7 volts and are charged to a maximum of 4.2 volts.

Your Triton also offers a Li-Ion setting. This is designed for Li-Ion cells that have a nominal voltage of 3.6 volts and are charged to a maximum of 4.1 volts. Most of the current Li-Ion cells currently available have a nominal voltage of 3.7 volts and are charged to a maximum of 4.2 volts. You can charge a 3.7 volt cell to 4.1 volts with the only problem being reduced voltage and reduced capacity.

The CR123 battery size has several rechargeable options. The rechargeable version of the CR123 is usually referred to by putting an "R" in front. Thus we have R-CR123, or RCR123. In this size, we have some options on voltage. A bare cell made from cobalt chemistry is just like a Li-Po or our current Li-Ion cells. It has a nominal voltage of 3.7 volts and charges to a maximum of 4.2 volts.

This is where the problem arises. You have a light that is expecting primary cells with a voltage of around 3.0 volts, and you pop in a Li-Ion cell with a voltage of 4.2 volts. Sometimes this can fry the circuit. The problem is amplified when you go to multi cell lights.

By adding a circuit to the cell, the 4.2 maximum volts can be dropped down to a more respectable 3.6 volts, or somewhere around that, so we had an introduction of R-CR123 3 volt cells. Because of the voltage drop, these cells need to be charged with a special charger that charges to a higher voltage. With these cells you purchase the cell and charger as a package and make sure you do not charge other R-CR123 cells on that charger.

With the introduction of the Li-Fe chemistry, we now have another option in the R-CR123 size. This chemistry charges to a maximum of around 3.6 volts, and has a nominal voltage of around 3.2 volts. While this seems like a good fit, these cells, regardless of how they are labeled, take a hit on capacity.

An example of this can be found with the A123 Systems cells. A123 recently came out with a cell in the 18650 size. It has a capacity of 1200 mAh. Other 18650 sized cells have capacities in the 2400 - 2600 mAh range.

Unfortunately, I don't believe your Triton is not set up to charge Li-Fe chemistry. This chemistry needs to be charged to a maximum of around 3.6 volts, but since the chemistry is more forgiving, you can sometimes charge to 4.1 volts, realizing that you do so at your own risk. The risk is that you may destroy the cell, not that you will create a fire hazard.

There are "daptors" available that allow you to charge Li-Fe chemistry with the Triton, but you may find the cost prohibitive. You will have to browse the RC sites to find them.

There is some confusion associated with the R-CR123 sized battery. The chargers between the different types are not compatible with other types, so the general rule has been to purchase cells and charger together, mark them, and make sure you only use the charger designed for the specific cell you are using.

If all of this seems a little confusing... it is. Some have gotten fed up with the reduced capacity and the charging confusion associated with this size and have moved on to lights that take the larger size cells. For example, the 17670 size Li-Ion cell is the same size as 2 of the CR123 cells. The problem here is that a single Li-Ion cell comes off the charger at 4.2 volts, and spends most of is discharge at around 3.7 volts. 2 CR123 cells start off at around 6 volts, and spend a lot of their discharge time at around 4.2 volts. If your light is able to work well at the reduced voltage of the 17670 cell, you are good to go. The 17670 cell has around 1400 mAh of capacity, which is about the same as primary cells. This offers improved runtimes over the Li-Fe cells, which seem to test out at below 400 mAh.

Tom

 

[matrixshaman]

Not sure if anyone else answered this part but the 14500 is a AA size Li-Ion that is 3.6 volts - hot off charger around 4.2 volts. I think your fenix would go if you used it. Info form Silverfox is right on - he's our Grand High battery Guru

 

[UnknownVT]

Not sure if anyone else answered this part but the 14500 is a AA size Li-Ion that is 3.6 volts - hot off charger around 4.2 volts. I think your fenix would go if you used it. Info form Silverfox is right on - he's our Grand High battery Guru

OK if you bought a Fenix P2D-RB100 - a single CR123 light -
the head (common to the L2D-RB100, and if there were such a thing the L1D-RB100) - is rated 0.9-4.0V - so you can use a single 3.7V RCR123 rechargeable Li-Ion battery in it - this will give a noticably brighter Turbo/max than on primary (non-rechargeable) CR123A - BUT all the lower modes will also be about as bright - so you go from a light that has 4 levels of light to a single level light albeit very bright. (reason: the battery voltage Vin exceeds the Vout (set to Vf of the LED) - so the regulating circuit is by-passed and the light is essentially direct-driven by the 3.7V battery).

On a single AA body tube - eg: the L1D body - you can use a single 14500 AA sized rechargeable Li-Ion battery which is also 3.7V - with the same/similar behavior as the 3.7V RCR123 rechargeable Li-Ion.

However there are 3.0V R-CR123 rechargeable Li-Ion batteries - these are sometime called "regulated" batteries - where additional circuitry is added to regulate the voltage down to 3.0V - they claim to be a "direct replacement" for a primary (non-rechargeable) CR123A - this would probably allow the Fenix P2D-RB100 to behave as intended as if on a primary CR123A - however the capacity is fairly low due to the additional circuitry.

Similarly you would probably get better performance using 2x NiMH rechargeable AA batteries in the L2D (2x AA) body over plain alkaline batteries. It's probably better to get the LSD (Low Self-Discharge) batteries such as eneloops or the Kodak Pre-Charged ($7.88/4 at WalMart). You could also use the nominally 1.5V primary Lithium AA batteries (non-rechargeable) like the Energizer Lithium e2 - but these are just expensive.

If you do decide to use 3.7V rechargeable Li-Ion batteries - then the advice is not to have the light on for extended periods, as the light will get hot.

 

[mdocod]

worth a read:
http://www.candlepowerforums.com/vb/showthread.php?t=190508
for your next purchase..

1xCR123 size flashlights tend to have less than ideal rechargeable solutions. If you are serious about using Li-Ion, and want a lot of capacity in a compact space, 18650 size cells are the way to go. They are about double the length of a CR123, and about 2mm thicker, but have about the same energy as a 2xCR123 primary stack, but it's rechargeable. You can make great use of your hobby charger to top up 18650 size Li-Ion cells in a simple custom cradle you can make out of wire and wood and screws. Then you just need to find a light that supports the cell.... check out wolf-eyes, dereelight, pila, lumapower, tiablo, and many more.

 

[fatboy]

OK, guys, great input, lots to comprehend, research and understand.

I ordered a 2XAA body and tail today for this head.

Matt @ fenix-store explained to me:

The head I have does NOT have a regulator built-in. Only the P3D does, so no rechargeable Li-Ions allowed in either the CR123 or 2XAA mode will work without risking, and probably will "let the smoke out" of the circuitry of this head and nuke the warranty.

I'm pretty convinced the charger would work fine based on everyones input, which is great to know.

Perhaps a little hacking is in order on the light, "just to see if it'll work" at some point.

Like I said tho, more research and understanding is in order before I start tweaking.

 

[fatboy]

OK, sorry, I see you bought a CR123A rebel, you threw me off with that 2AA tube

What is the exact model of the Fenix Rebel light that you purchase?

Sorry for not responding.

P2D is what I have and a L2D body/tail on the way. Along with the L1T, these all use the same Rebel head.

I think I see a new Cree on the horizon :naughty: