AW the same as 'high drain'?

[Sewknitty]

I wandered on over to Lighthound to check out some high drain 18650's and 14500's and found this beauty: AW 18650 Protected 2900 mAh Rechargeable Lithium Battery

It says 'AW', which I think I've seen on high drain batteries...or do I see IMR on them?

How can I tell which are high drain? Will they say either, both, neither...?

Thanks in advance!

 

[mdocod]

The black label protected cells (in fact, almost any cell that is "protected" from any brand) is always a Lithium Cobalt chemistry li-ion cell. Maximum safe drain rates will be in the 1-2C range depending on the manufacture. AW has been souring cells for years capable of 2C rates reasonably well. These are NOT "IMR" (Lithium Manganese Oxide) "high rate" cells, however, when you have a cell with as much capacity as an 18650, there isn't really any NEED for the high rate capable cell. Those 2900mAH AW cells are re-badged and protected Panasonic made cells. They are about the safest and highest performing LiCo chemistry cell on the planet right now and can easily deliver 5+ amps just fine which is far more than you will ever likely use in an ecig application.

The AW brand "high drain" cells are red label cells sold as "IMRXXXX0."
Example: http://www.lighthound.com/AW-IMR-14500-LiMN-Rechargeable-Lithium-Battery_p_3644.html
(those are what I use in my BB)

I would say that for 90+% of ecig applications, any cells 17500 size or larger can be LiCo chemistry and handle the current safely and with decent performance. The remaining 10% would be custom "multi-atty" or ultra-low-resistance customs. For smaller cell sizes, everything should be LiMn chemistry. LiFePO4 is really not a high drain chemistry unless it has nano tech to increase the surface area and reduce the resistance of the cathode, which is really only found in A123 cells.

Eric

 

[Sewknitty]

Thank you, Eric! So I'll go ahead and put a couple of these babies in my cart. So, if I understood correctly, you're saying the 18650 provides power capably enough they don't need to be high rate to be spiffy. Did I get that right?

I have a couple LifePO4 CR123a batteries. What would you recommend instead? I was thinking of getting 16340 Li-Ion to use in a pair.

 

[cappadoc]

I'm not Eric, but LiFePO4 is the only native 3V battery. 16340's are 3.7V. These are fine for VV, but if you want 6V, you need the LiFePO4 or the Tenergy 900mAh blue Li ion's that have a diode to lower output to 3V. These cells require a special charger and are not particularly well regarded by most battery geeks. I would suggest the AW LiFePO4's for 6V applications.

 

[mdocod]

If your 18650 application is pretty normal, like running a typical atty, or even a LR atty, then the 2900mAH AWs are a great choice. There are IMR18650s available, but they are about half the capacity. There isn't much to gain performance wise until you are operating loads in excess of 4-5 amps. A 1.5 (very LR) Ohm atty/carto is still less than a 3 amp load. The 2900mAH capacity will deliver in excess of an hour of continuous "on" time for the PV when driving a LR atty.

As for the LiFePO4 type RCR123s. I haven't seen discharge charts for anything but the AW brand. basically, they seem to hold up reasonably well until about 2 amps, above that they fall on their face. Whether or not these are appropriate for a given configuration would depend on the resistance of the load. I would suggest 3 Ohm or higher for a pair of such cells. However, using low-resistance atty's with single larger format cells can produce similar performance and much better operating times for the same size PV.

Eric

 

[mdocod]

I'm not Eric, but LiFePO4 is the only native 3V battery. 16340's are 3.7V. These are fine for VV, but if you want 6V, you need the LiFePO4 or the Tenergy 900mAh blue Li ion's that have a diode to lower output to 3V. These cells require a special charger and are not particularly well regarded by most battery geeks. I would suggest the AW LiFePO4's for 6V applications.

Yea, avoid those diode bucked LiCo cells like the plague for these applications, they are NOT suitable nor safe here.

The terms RCR123 and 16340 in and of themselves have very little to do with voltage or chemistry. The term "16340" tells is the size of the cell. It could be a 1.2V NIMH cell or a 3.2V LiFePO4 or a 3.7V LiCo or LiMn or even a standard CR123 primary or anything else sharing the same size. The Term "RCR123" is only slightly more specific in that we know for certain that it is a rechargeable cell likely to be ~3V or higher sharing the "CR123" size, or 16340 size. I have seen the term RCR123 and 16340s both used interchangeably in the industry for product descriptions for years for all sorts of cells rated in the 3.0-3.7V range.

---

As for the 6V operation, I think I would suggest looking for even higher resistance atty's, like 4.5 Ohm or better, and running a pair of 3.7V IMR16340s instead. This would probably deliver better operating time and performance than running LiFePO4 cells into a ~3 Ohm load. Though, a single 17670 running a LR atty would have better operating time still, though not quite as hot. If this was an SB or other similar 18650 mod, then hands down, the single 18650 stores far more energy than pairs of any type of 16340 size cell.

Eric

 

[WillyB]

I wandered on over to Lighthound to check out some high drain 18650's and 14500's and found this beauty: AW 18650 Protected 2900 mAh Rechargeable Lithium Battery

I wouldn't bother with the overpriced 2900, in the tests I've seen the AW2600's have outperformed the Panasonics as far as voltage drop, and for our vaping uses the AW2600 should also give longer vape times.

AW 18650 Protected 2600 mAh Rechargeable Lithium Battery

 

[mdocod]

You might also check out redilast cells. They are becoming popular pretty quickly as they are also made from top teir cell manufactures. My only concern with them is that I suspect that the cells may be harvested from laptop packs that developed other problems. (I can't confirm this but have plenty of reasons to believe this).

Eric

 

[Sewknitty]

Thank you, Eric, Cappadoc and Mdocod. Here's what I'm going to do: hang onto my Ultrafire 2600 mAh 18650's until I check out the various brands. They were awesome in the beginning but I feel they're falling off a bit after 8 hours. Maybe it's just me preferring 6 volts but I swear some of the oomph is fading so I'm buying replacements soon. For right now, I'm investing in a pair each of AW LifePO4's and IMR16340's to see which I prefer. I have HV attys (3.5 and 4.5 ohm) to use with both.

I'm so glad I asked! Thank you again.

 

[mdocod]

The IMR16340s have about double the energy density compared to the LiFePO4 RCR123s.

On the 3.5 Ohm atty running the LiFePO4 cells, you can expect ~5-12W vaping (depending on state of charge and cell temp) with an estimated operating time of ~13 minutes.
On the 4.5 Ohm atty running the IMR16340s, you can expect ~6-14W vaping (depending on state of charge and cell temp) with an estimated operating time of ~20 minutes.

Eric

 

[Sewknitty]

The IMR16340s have about double the energy density compared to the LiFePO4 RCR123s.

...
On the 4.5 Ohm atty running the IMR16340s, you can expect ~6-14W vaping (depending on state of charge and cell temp) with an estimated operating time of ~20 minutes.

Eric

Hmmm, I don't know how to translate this. So, energy density...double the amount is a good thing for longer output ...seems the wattage is also higher... Can you tell me how to translate watts to ohms, please?

 

[mdocod]

You'll notice I like to use this little symbol a lot: "~"

When used with numbers, that symbol means similarity, but not exacting equality. I bring this point up first, because I answer these types of questions and run the numbers from memory of studying charts.

There are many ways in which to calculate the approximate performance of a given battery configuration into a given load.

*Find out or estimate the total resistance of the cells in the circuit, add to that the resistance of the rest of the circuit, and produce a pair of data points on the high and low end of the state of charge for the cell. Calculate for voltage drop and current across the load and total power at each data point. Calculate average load and divide the true tested capacity of the cells by that load for an estimated runtime.

or...

*Ballpark the expected current flowing in the circuit by studying discharge charts of the cells in question in conjunction with calculating for current flow based on expected load, pick 2 data points (again, high and low states of charge) that are the expected operating voltages given the expected current draw of the circuit. Calculate current across the load. Calculate average load and divide tested capacity by that load for an estimated runtime.

or...

etc etc....

Everything is calculated with Ohms law and information from discharge graphs or estimated true cell capacity and performance.