AW & Tenergy 3.0V LiFePO4 RCR123 Runtime Tests

[turboBB]

In my quest to find the best rechargeable cells for my SF lights, I recently picked up some AW LiFePO4's rated at 500mAh capacity and then put it to the test against Tenergy's LiFePO4 offering (rated at 750 mAh).

In anticipation of using these in a M3LT, the cells were tested in a Lumapower VX Ultra which has been stated to draw approx. 2.1A on high.

Starting/Ending V (IMR thrown in for comparative analysis):
AW - 3.78/2.95
Tenergy - 3.75/2.94
IMR - 4.18/2.73

I've found that the LiFePO4's come off the charger at approx. 3.8v but will settle down to about 3.5ish after a few hours or so. I usually run the cells down a little further to about 3.3v before shoving them in SF lights just to be safe but since the VX Ult was designed for RCR's I simply conducted the tests shortly after the batteries came off the charger.

Here is the result:

X axis = Time (Min) / Y axis = Relative light output

Test conducted w/fan on. Surface temp of light @ the head was 81.5F at start and never got more than 86.5F throughout the tests. EDIT: For the LiFePO4's, I actually shut off the light @ approx. 53 min as I didn't want to over discharge the bat's.

Given the oft exaggerated stated capacities by certain brands and how highly vaunted AW's cells are, I was actually expecting the AW's to do better but it seems it got bested by the Tenergy (even if slightly). I plan on running the tests again as it seems there is some anomaly w/the level that the AW's started off at before it took a nose dive.

Cheers,
Tim

 

[45/70]

Re: AW & Tenergy LiFePO4 Runtime Tests

I'm curious turbo, what charger are you using to charge the LiFe cells? I ask because their voltage seems high, even right off the charger. With my WF-138, or my hobby charger, cell voltage is rarely 3.60 volts off the charger. After a few minutes it is usually in the 3.35-3.45 Volt range, depending on which charger and rate I use.

Dave

 

[turboBB]

Re: AW & Tenergy LiFePO4 Runtime Tests

Hi Dave,

It's the Tenergy charger that comes in the combo:
http://www.batteryjunction.com/6rcr123a-combo.html

Still waiting for my CellPro PL8 to ship so have to make do with this charger for now.

Will try a different light and see what kind of results I get and will post the results here. I had really high hopes for these AW's given the limited options for 3.0V RCR123's out there.

Cheers,
Tim

 

[45/70]

OK Tim. Just for the heck of it I just charged two DX 17340 LiFe's on my WF-138. The end voltage for both was ~3.32 Volts. My Supermate DC6 never goes above 3.60 Volts during charging, so the voltage could never be higher than that, but I believe the cells come off it a bit higher.

Thanks for the info, I didn't mean to sidetrack your thread. I was just curious.

Dave

 

[turboBB]

Dave,

Yeah, these are being overcharged a bit so I usually try to monitor charging and pull them when the LED goes from Red to Red/Green (Green = Fully charged).

How do you like the DX cells and do you have any other LiFePO4's to compare them to? I notice the size is 17340, can they fit in stock SF lights (specifically E2DL or U2A since those seem to be tight fit vs. say a G2Z).

Here are two more charts, again the Tenergy bests the AW's in each.

Zebralight SC30 - 1 cell (anomaly uptick for IMR is due to me finding sweet spot for light meter to capture max lux):

Surefire E2DL - 2 cells (anomaly uptick at beginning of Tenergy run is due to me finding sweet spot for light meter to capture max lux):

Unless these just so happen to be a low performing AW's, the Tenergy cells have definitely held their own.

EDIT: (Unscientific but here goes...) Using the E2DL as the baseline and taking into consideration that the runtime to < 50% as quoted by SF for High is 1.9hrs (114min) and on primaries (usually @ 1550mAh), then the 39 min to < 50% output for the AW's is approx. 34% of which would yield 527 mAh and is pretty accurate for the rating. The Tenergy would be 43 min to < 50% output is 37.7% less than primaries and would yield about 584 mAh. Overrated they are but at least they currently are the best bang for buck and run time @ $3.29 from BtyJunc vs. $6.49 per pop for the AW's from Lighthound (where I made each respective purchase).

Cheers,
Tim

 

[turboBB]

As a follow up post, I completely forgot to take into consideration that the AW's are brand new and have not even gone through a few cycles yet. This came to light when the v drop on the AW cells have now slowed down past the Tenergy (e.g. charged them both up after testing w/the AW on 3rd cycle and after few hours, v for Tenergy was 3.51 vs. 3.57 for AW). Initially, the AW's were dropping faster than the Tenergy's.

I'll need to completely re-run these tests after a few more cycles.

Cheers,
Tim

 

[45/70]

You're doing fine, Tim.

How do you like the DX cells and do you have any other LiFePO4's to compare them to? I notice the size is 17340, can they fit in stock SF lights (specifically E2DL or U2A since those seem to be tight fit vs. say a G2Z).

I haven't ever run these cells on the CBA or anything, so I don't really have an accurate idea of their capacity. It's a bit hard for me to even guess, as I run them probably harder than I should sometimes (x2 in an Aleph 2, SSC P4U, DB 1000, for example) but I'd guess they are 300-400mAh. of course at lower rates they may do a bit better than that, but probably not much.

I did run six DX LiFe 15270 LiFe cells on my CBA, if you're interested. Those are my graphs on the page. They have "800mAh" on the side, but I knew better before I even ordered them. Hey, 200mAh out of 800 ain't bad! :naughty:

As info, the17340's are this version. I have eight of them and also use them in high output single cell applications, as well. Overall, they do what I want and perform as expected.

Dave

 

[DHart]

So Tim... are you liking these Tenergy's as a power source for your Surefires?

I've ordered a set of them to run in my E1B and Streamlight TLR-1 weapon light. I'm hoping they give good performance so I don't have to keep stuffing lithium primaries into these lights indefinitely.

 

[turboBB]

Yes, I'm not a big fan of primaries (trying to be green). My next quest is to come up with a solar charger hooked up to 12V bty so I can run the charger off of it via an automotive adapter (I got the set w/6 batteries and charger w/12V DC car cord).

Leaving green out of the pic, even if you could source quality primaries cheap, they still will avg. more than $.80 ea and that can quickly add up to make you By now, I've already saved money over using primaries w/the amount of cycles used.

Keep an eye out on the final charge state. For some reason my particular charger tends to charge these up pretty high (roughly 3.8-3.9v). I've read/heard the ideal top v after charging should only be around 3.6v.

Also, in spite of inital v ratings (usually around 3.39v for LiFePO4 and I've seen as high as 3.29v for fresh primaries) under load, the LiFePO4's will avg. 3V (hence the nominal v rating) and primaries are around 2.5V. I'd be wary of running it in anything over 2x cofig without knowing for certain the v-range that a particular light can handle.

I've run 2x in U2A (SSC version) and E2DL (200L) without any issues so far (and a search of related threads had voiced as much by fellow CPFers). I've also run 1x on a KL4 head.

I'm dying to try 3x in my M3LT but just worried it'll go

Best of luck and lemme know how you like them.

Cheers,
Tim

 

[turboBB]

@ Dave, thx for the info! I could've sworn I had replied to this but guess I never hit submit...

 

[Black Rose]

It's too bad that you have to use the Tenergy charger with the Tenergy LiFePO4 cells.

I already have a charger capable of charging LiFePO4 cells.

 

[Beacon of Light]

It's too bad that you have to use the Tenergy charger with the Tenergy LiFePO4 cells.

I already have a charger capable of charging LiFePO4 cells.

I do recall seeing that caveat in Battery Junction's site for the Tenergy LiFePO4 cells, but I think they were being cautious as they didn't want people chsarging them on 3.6v/3.7v chargers since it is a 3.0v cell. I have the 3.0v/3.6v RCR123 charger and haven't had any problems. That said I'd like to know I'm not playing Russian Roulette and my odds are running out without any disasters to speak of. I think I;d be double dipping or in for double trouble as I have a Tenergy 750mAh I just used for a runtime test and on the meter it is 1.529v so not sure what happens when I place it on the charger being that low.

 

[45/70]

I have the 3.0v/3.6v RCR123 charger and haven't had any problems. That said I'd like to know I'm not playing Russian Roulette and my odds are running out without any disasters to speak of.

Beacon, the biggest danger in all of the possible combinations possible when charging the three types of RCR123 cells, is placing a regular 3.6/4.2 Volt LiCo cell in a charger meant for a "3 Volt" LiCo cell.

The "3 Volt" LiCo cells have two diodes under the positive nipple. One works to reduce the voltage of the cell to "3 Volts" (actually more like 3.2-3.8 volts, depending on the load applied) during discharge, and the other diode is installed so as to allow the cell to be charged (diodes only allow current to pass in one direction, thus the need for two diodes).

When attempting to charge a "3 Volt" LiCo cell, the necessary addition of the "charging" diode (that allows current to go into the cell, in order to charge it) requires that the charging voltage (actually the CV stage voltage) be higher than that which is required for charging a "normal" 3.6/4.2 Volt LiCo cell. This voltage is usually 4.4-4.5 Volts. So, if you attempt to charge a "normal" 3.6-4.2 Volt LiCo cell in a charger meant for a "3 Volt" LiCo cell, you will be overcharging the cell, very possibly to a dangerously high voltage.

In your case, the "3.0V" volt setting on your charger is meant for charging LiFePO4 cells, as are all of the "dual voltage" chargers that I am aware of, not "3 Volt" LiCo cells. The "3 Volt" LiCo chargers are, as far as I know, all dedicated "3 Volt" LiCo cell chargers, and only charge this type of cell.

All other combinations of RCR123 cells and chargers, are relatively safe, although mismatched charging is obviously not recommended. Some combinations for example, will result in overcharging LiFePO4 cells, shortening their cycle life, such as charging in a "normal" 3.6-4.2 Volt, or especially in a 4.4-4.5 Volt "3 Volt" LiCo charger. Other combinations will result in a barely charged cell, such as attempting to charge a "3 volt" LiCo cell in a LiFePO4 charger, or only about half charged if charged in a "normal" 3.6-4.2 Volt LiCo charger. Again, it's always best to use the proper charger when charging any Li-Ion cell, of course.

Dave

 

[tobrien]

I have some questions for yall abut the LiFePO4 batteries that have been bugging me:

1. when is it best to use these LiFePO4 batteries over 'regular' chemistry Li-ions?

2. is one of the takeaway messages from this thread that the LiFePO4s can be used, at least with the AW brand, in Surefires safely? I ask because aren't their (the AW LiFePO4s) voltage ratings 3.2 VDC?

3. do CC/CV chargers, like the XTAR WP6 II, work okay for the AW LiFePO4 batteries? I'm assuming not, since the charge voltage is 4.2V, however, LiFePO4 chemistry is safer, so would it matter at all if you overvolted it?

sorry for all the questions, I'm really intrigued by the different batteries haha

 

[45/70]

Hi tobrien. I'll try to help a bit here, but my applications differ somewhat from yours.

1. I am replacing my "3 Volt" LiCo cells, that I mentioned previously, in lights that will work with regular 4.2 Volt LiCo cells, but are basically over driven. Examples are my older Peak single cell CR123A lights. The output with LiFePO4​ cells, to the eye anyway, is not really distinguishable from the higher voltage LiCo cells. The advantage is though, that the lights run quite a bit cooler, with the LiFe cells.

2. This is where I can't really help you, as I no longer own any Surefire lights. I've opted to spend the money on custom lights in their stead. I wouldn't think however, that a SF LED light would complain about the slightly higher voltage of the LiFe cells. On the other hand, I have no doubt that the incandescent variety may suffer from shortened bulb life and/or possibly "instaflash" using LiFe cells. The Surefire and other drop in incandescent bulbs for these lights are driven pretty hard as it is, so an extra two tenths (or possibly even more) of a Volt may cause problems. I'll let others comment on this though.

3. You could probably use the XTAR WP6II to charge LiFe cells, but it's not a good idea. It's unlikely that you would experience a "vent with flame" incident or anything, but you would be grossly overcharging the cells. This would certainly shorten cell life considerably. So anyway, I wouldn't do it, except maybe in an emergency.

Hope this helps, some anyway.

Dave