Failure of one 16650, as a substitute for two RCR123As.... but what WILL work??

Hi,

Based on my previous thread, I'm assuming that a single battery replacement for 2X rechargeable RCR123A 3.0V 750mAh's is going to require a lot more thought.
http://www.candlepowerforums.com/vb...23A-lithium-batteries-VERSUS-one-big-one-help


I bought these:

http://www.amazon.com/gp/product/B00PDNYL4A/?tag=cpf0b6-20

When fully charged, THEY DON'T WORK.

While I would not consider my purchase a "stupid" purchase, I seem to be lacking in the ability to
judge the very specific parameters of batteries correctly. I DO know that I need to return the product very soon.

My flashlight uses rechargeable 2x RCR123A 3.0V 750mAh
My goal is to replace the two "little" rechargeables, with one big one.

This isn't as easy as I thought would be.

waxycap said:

Hi,

Based on my previous thread, I'm assuming that a single battery replacement for 2X rechargeable RCR123A 3.0V 750mAh's is going to require a lot more thought.
http://www.candlepowerforums.com/vb...23A-lithium-batteries-VERSUS-one-big-one-help


I bought these:

http://www.amazon.com/gp/product/B00PDNYL4A/?tag=cpf0b6-20

When fully charged, THEY DON'T WORK.

While I would not consider my purchase a "stupid" purchase, I seem to be lacking in the ability to
judge the very specific parameters of batteries correctly. I DO know that I need to return the product very soon.

My flashlight uses rechargeable 2x RCR123A 3.0V 750mAh
My goal is to replace the two "little" rechargeables, with one big one.

This isn't as easy as I thought would be.

Click to expand...

Why haven't you told us what flashlight you're using?

Chris

waxycap,

I'm afraid your quest for a single rechargeable cell for this light is a fruitless one. In your previous thread there was a link to another thread, post #24 in that thread by Greenbean states his HL would work with the cell at 4.18 volts but would only flash at 4.12 volts. So, even had it fired up with a fully charged battery,. . . the run-time would have been brief, very brief.
Your light has a voltage threshold that a single cell can't meet. Seems your current fuel is your only rechargeable option, unless you can find others on the forum that have had success running two LiCo 16340s. Be aware that the LiCo batteries are of significantly higher voltage than the LiFePO4 batteries you are using now and may damage your light. Tread carefully in this regard.

Sorry to be the bearer of not so great news!

waxycap said:

Hi,

Based on my previous thread, I'm assuming that a single battery replacement for 2X rechargeable RCR123A 3.0V 750mAh's is going to require a lot more thought.
http://www.candlepowerforums.com/vb...23A-lithium-batteries-VERSUS-one-big-one-help


I bought these:

http://www.amazon.com/gp/product/B00PDNYL4A/?tag=cpf0b6-20

When fully charged, THEY DON'T WORK.

While I would not consider my purchase a "stupid" purchase, I seem to be lacking in the ability to
judge the very specific parameters of batteries correctly. I DO know that I need to return the product very soon.

My flashlight uses rechargeable 2x RCR123A 3.0V 750mAh
My goal is to replace the two "little" rechargeables, with one big one.

This isn't as easy as I thought would be.

Click to expand...

Hi.

Not sure how you will be able to return the batteries, as I suspect they are working fine. Unless the seller accepts them as a good will gesture.

With regards to why it doesn't work. My guess (a guess as I don't know much about the light you have), is that the driver it uses is a buck driver designed for 6+ volt input.

To help understand this. Most Cree LEDs in lights like this require an input voltage of 3.x volts. And to maintain high output you need to sustain the voltage to the LED at this level. There are many ways of achieving this. Streamlight appear to have opted for a buck driver, this takes a high voltage input to the driver, which will buck it down to the correct voltage for the LED. This usually makes for a good stable output (constant output regulation). Although this will depend on how they have decided to profile the discharge curve and output curve.

In this instance it appears that the driver won't work on lower input voltages. This is probably done as part of a low voltage protection, i.e. if 2xCR123a's reach 2'ish volts each, they are deemed pretty flat, and to avoid over discharge the light probably shuts off once the battery combined voltage is at 4.5'ish volts or under.


A single Li-ion is only 4.2 volts fully charged. So in this instance simple isn't an option.


There are other lights that have a wider voltage support and will work on single or multiple battery voltages. But it appears not this one.

As I see it, you have some options:


1. Stick with CR123a or rechargeable RCR's (make sure the right voltage), although the latter usually give very short runtimes.

2. Look at modifying the light with a new driver that works on 4.2v, many people mod lights. Although my guess is, the Streamlight will not be mod friendly.

3. Get a different flashlight that does run on a single li-ion.


This is a new light just out. It runs on a single 18650 (but won't run on 2xCR123a, as it only supports up to 4.2v).

Eagle Eye X6R
http://www.banggood.com/Eagle-Eyes-...USB-Rechargeable-LED-Flashlight-p-962933.html


Get a good Li-ion 18650 and I think you'll be really pleased.

And all for $27.99 for the X6R and you can choose if you want Cool White or Neutral White for the emitter. (I prefer the latter).

Up All Night said:

waxycap,

I'm afraid your quest for a single rechargeable cell for this light is a fruitless one. In your previous thread there was a link to another thread, post #24 in that thread by Greenbean states his HL would work with the cell at 4.18 volts but would only flash at 4.12 volts. So, even had it fired up with a fully charged battery,. . . the run-time would have been brief, very brief...

Click to expand...

Interesting that Fivemega links that post in and then says a 17670 WILL work..

"3. Get a different flashlight that does run on a single li-ion."

Now you are thinking like I am thinking. I should probably just keep the two batteries I bought and use the purchase as an excuse to shop for a backup flashlight that is compatible.

I'd actually be willing to spend more than $27.99 though, because I need something at least comparable to my ProTac HL. Any more suggestions? Based on the batteries I bought? Anything that's not too much of a thrower.

One more question. There must be some higher quality rechargeable RCR123's out there. Any suggestions on ones compatible with my ProTac?

Ahh, I know. I'd also like to consider a more powerful flashlight that would take both 16650's for power. Is there a way to browse Candlepowerforums for flashlights by battery type alone?

@ Up All Night.

Thank you for clarifying what boat I am in. My only next step would be to find the highest quality RCR123's, but it looks like the Tenergy brand is what I am stuck with.
The most important part is getting the voltage of the battery to match up exactly, right? And mAh basically just indicates better runtime the higher the number?

I would stick with AW protected cells if I were you - it's a quality brand name that many here trust and you do not want to take any chances with lithium cells used in series. 16340/RCR123s mah ratings are already a misnomer, you'll be lucky to get 650 mah out them... I would argue that any manufacturer claiming more than 750 actually has less than average mah (BS exaggerating marketing integrity of XXXXfire type cells). The best would be to do the research on HJK's site: lygte-info.dk.

Any quality brand will do...there are already tons of thread about what brands actually deliver on their claims. No need to pay the very high premium for AW cells, unless you have a specific need. (They are some of the shortest protected cells, I have a couple AW 14500s for that reason.) You can get quality cells that use the same Panasonic base cell for much less from other brands.

The problem I am having with the Tenergy brand is that most of the batteries turn out dying on me in one year to six months. I've gone through entire batches of them.

I bought six less than a year ago and now I'm down to two, with a third I can't use because I need just one more to power my flashlight.

So the question for me is not some silly debate over whether or not I can squeeze five extra run-time minutes out of a certain battery because of it's specs, but more along the lines of:

"Will these damn batteries last?"

waxycap said:

The problem I am having with the Tenergy brand is that most of the batteries turn out dying on me in one year to six months. I've gone through entire batches of them.

I bought six less than a year ago and now I'm down to two, with a third I can't use because I need just one more to power my flashlight.

So the question for me is not some silly debate over whether or not I can squeeze five extra run-time minutes out of a certain battery because of it's specs, but more along the lines of:

"Will these damn batteries last?"

Click to expand...

For the 16550 size cell (17670 with PCB added) you'll want the Sanyo 2000mAh, or the newer 2500mAh cells, either naked, or protected.

I bought two Redilast 17670s with the Sanyo ~2100mAh cells inside and they work well in my SF 6P with Redilast 3 mode XM-L2 U2 P60 drop-in.

Stick with the Big 5 if you can: Sanyo, LG, Samsung, Panasonic and Sony.

Chris

I use the 16650's in my FourSevens QT2L-X.

Initially I thought it would be a sweet light with my rechargeable Nitecore RCR123 650mAh batteries. Quickly i realized that 2 batteries in series do not double the mAh, just the volts.

2,500mAh KeepPower 16650's do it proper justice.

ChrisGarrett said:

For the 16550 size cell (17670 with PCB added) you'll want the Sanyo 2000mAh, or the newer 2500mAh cells, either naked, or protected.

I bought two Redilast 17670s with the Sanyo ~2100mAh cells inside and they work well in my SF 6P with Redilast 3 mode XM-L2 U2 P60 drop-in.

Stick with the Big 5 if you can: Sanyo, LG, Samsung, Panasonic and Sony.

Chris

Click to expand...

Yeah, but I thought we were talking about how a 16550 battery can work in a specific flashlight... namely my Streamlight ProTac HL.

You can only use batteries of very specific parameters based on exactly what flashlight you have to work with. Ultimately, I would like to have the most flexible high-output flashlight possible combined with the most flexible type of battery. Are you suggesting that it does not matter how much the mAh varies? Perhaps it only matters that the voltage matches? And what about a spec called "Wh"? On one of my batteries for the EagleTac, it is listed as "12.6Wh" I have only seen the "Wh" spec listed on these batteries...

For the ProTac HL from Streamlight I very strongly recommend the K2 LFP123. They last almost as long as primary CR123's when run in high output mode.

germanium said:

For the ProTac HL from Streamlight I very strongly recommend the K2 LFP123. They last almost as long as primary CR123's when run in high output mode.

Click to expand...

Actually, they shouldn't last nearly as long.

Panasonic USA sourced CR123As have 1550mAh of capacity and the K2s are probably around 500-600mAh of capacity.

Chris

ChrisGarrett said:

Actually, they shouldn't last nearly as long.

Panasonic USA sourced CR123As have 1550mAh of capacity and the K2s are probably around 500-600mAh of capacity.

Chris

Click to expand...

Actually due to how internal impedances work with the K2 batteries compared to primary batteries the K2 batteries last about 30 minutes whereas the primaries while lasting overall longer they start to lose a lot of brightness after 35-40 minutes so not much difference at full brightness.

Yes indeed they are rated for 600mah but believe me they are an honest 600mah.

waxycap said:

You can only use batteries of very specific parameters based on exactly what flashlight you have to work with. Ultimately, I would like to have the most flexible high-output flashlight possible combined with the most flexible type of battery. Are you suggesting that it does not matter how much the mAh varies? Perhaps it only matters that the voltage matches? And what about a spec called "Wh"? On one of my batteries for the EagleTac, it is listed as "12.6Wh" I have only seen the "Wh" spec listed on these batteries...

Click to expand...

Watt hours (Wh) are the only way to go whenever the source voltage and load voltage vary, like in LEDs. I'm going to use some round numbers that have little basis in reality, but you can see where the concept is applicable. Take a rechargeable 4.0v cell with a capacity of 3000mAh. If the emitter being driven using 4.0v then a run time calculation is merely the mAh used by the emitter divided into the mAh rating of the cell. In this simplified world, an emitter using 1000mA (or 1000mAh in one hour) will run for three hours before the cell needs to be recharged.

Now let's take an example near and dear to my own heart, the USB Power Bank. I own a power bank that in this simplified world stores energy at 4.0v, and stores 10,000 mAh. That's 1000mA for 10 hours, 2000mA for five hours, etc. But, the output voltage we want is 5.0v. So we use some of that stored energy to raise the voltage available, at the expense of mAh of availablity. A 4v cell at 10,000mAH has a capacity of 40,000mWh, or 40Wh. [A x V = W] [10,000mAh X 4.0v = 40,000mWh] Now, if we draw that capacity out at 5.0v, how much capacity will we have? 40,000mWh ÷ 5.0v = 8,000mAh. We have used 2000mAh of capacity to raise the voltage from 4.0v to 5.0v. Now, of course this is assuming 100% efficiency in conversion, which never happens in real life. In Real Life one is lucky to get 80%, and 70% is probably closer to average.

Now, let's take your example. Your cell is rated at 12.6Wh. Find out the voltage being provided to the emitter by the driver circuit, and divide that into the Watt-hour figure to find the Amperes of capacity available. Multipy by 0.7 to account for voltage conversion losses. The number that remains will be the Ampere capacity available at that voltage - multiply by 1,000 to get mAh. If one knows the mA being provided to the emitter, it is easy to calculate the run time. Lumens Factory and Malkoff Devices are two vendors who I know provide the emitter draw in their specifications. Many vendors don't, and one has to measure it oneself, if possible. If you just want to convert that 12.6Wh back into a mA number you are more familiar with, just divide it by 3.7v (if it is a rechargeable, 3.0v if it is a primary) to get the mA available number.

I realize this was a long post, but I hope it helped understand the various ratings and how they interact. If you have questions, I will be glad to pontificate at any length to attempt to answer them. Accuracy not guaranteed, YMMV.

Good explanation.