Author Topic: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly  (Read 102010 times)

Offline FreeLancer

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I'm relatively new to this power source, with no personal experience with anything beyond the unprotected Sony VTCs I rescued from a Makita battery pack, and some protected 3400mah Nitecore cells for a multi-cell light I own.  I'd like some brand feedback from the rest of you on what's great, what's not so great, and what could wind up blowing up in my face.

So, to start off, the Nitcore cells seem great, I've measured almost twice the capacity of the salvaged Sonys, but they just barely squeeze into the magazine of my photon canon.

I know to avoid anything with "fire" in the name, but I don't know if that's an absolute rule, or what.

How about Orbtronic?  I keep hearing good things about them.

Offline Carl

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #1 on: December 24, 2015, 05:22:57 AM »
 :popcorn:  I want to keep up with this ....I stick to brand named cells , EFEST and PANASONIC are all I buy now..
Avoid "FIRE" in the name and anything labeled as or 3400 Mah( what I believe to be current top technology for 18650's.

Offline chad

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #2 on: December 24, 2015, 01:37:12 PM »
I'm new to this tech also as in just this last week, I bought a light and batteries based on the info I got from this thread. http://thesurvivalpodcast.com/forum/index.php?topic=56565.msg664816#msg664816

So far I'm real happy with my purchase.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #3 on: December 26, 2015, 03:46:05 PM »
Alrighty then......in the absence of data, I'm making a list of cells to test, focused on the high capacity (3400mAh) protected stuff, which I'm guessing are based on Panasonic NCR cells (I'm going to test them, too), and are $13 to $20 per cell from Amazon.

Here's my list of the premium cells I've found, so far:

Nitecore (obviously)
Orbtronic
Simon
Eastshine
Olight
Thrunite
EagleTac
Foxnovo

For comparison, I'd like to test some 'Fire' cells and would like suggestions on which brands the rest of you are curious about, and I'll try and get them, too.  If I can't get it on Amazon, I'm probably not going to hunt for it anywhere else.

I've got the following 'fire' cells:

Ultrafire
Tangfire


For testing, I've got a West Mountain Radio Computerized Battery Analyzer with the full software license, although I've never done more than constant power or constant current drain scenarios.  I'm in the middle of testing a huge lithium power pack for the next 36 hours, so I won't be able to mess with it until then, but if anyone has any suggestions on realistic test scenarios and how to do it with the CBA, I'm all ears.

Offline Carl

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #4 on: December 26, 2015, 04:38:10 PM »
There are considerable size differences and capacity capabilities in cells and often relabeled and recycled cells of varying life and capacity.

 http://lygte-info.dk/review/batteries2012/Common18650Summary%20UK.html

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #5 on: December 26, 2015, 05:29:31 PM »
I've added KeepPower to my list of premium cells, and Lingsfire and Thorfire to the "Fire" list.

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #6 on: December 26, 2015, 08:21:33 PM »
I was just doing some battery testing of my own on my 16340/RCR123s.  I don't have a tester, so I went by minutes of output out of the same flashlight with the light head wrapped in a coldpack to prevent overheating.  The test light was a JetBeam PC10.  These are all used cells of about the same age, two to three years old, rotated through my EDC and other lights, some may sit untouched for six months, others might get cycled from full charge to full discharge in under a week, but they all have the same chances of getting the same rest or abuse.

Ultrafire 880mah:
Five batteries tested.  High:  18:05, Low: 10:50, Average:  15:20 (dropping the lowest averaged 16:25)

Nitecore 650mah:
Four batteries tested.  High:  24:30, Low: 19:30, Average:  22:40 (dropping the lowest averaged 23:40)

That's a pretty substantial difference for name brand vs. "fire" branded batteries, especially given the claims of greater capacity by the Ultrafires.  I have some Olight branded batteries around and when I round them up I'll post the results back here.

After this test and also after reading yet another story about a flashlight blowing up because of a bad 18650 Ultrafire battery, I'm probably going to toss my Ultrafire RCR123s out of rotation and into SHTF usage only and buy a few more better quality cells.  I know the Olight batteries can be had for under $4 a piece, so if they measure up to the Nitecore, I'll get them, otherwise I'll get more of the $6 Nitecores.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #7 on: January 03, 2016, 11:49:25 PM »
I ran 10W constant drain tests, from full charge to 2.8V, on the three "fire" brands that have arrived thus far.  These were all charged on a Foxnovo charger at its lowest rate of 0.5A, since the premium cells were occupying the NiteCore D4, which charges at a gentler 375mA. 


The Good

ThorFire  $15/pair    3000mAh    48g

Test Result: Cell #1 - 2.46Ah    Cell #2 - 2.47Ah    82% stated capacity

The performance and consistency of these ThorFire cells deserves further attention.  I knew after weighing all the cells that these had much more in common with the premium cells than the "fire" crap, and the charge times added further to what the testing eventually proved.  These could very well turn out to be the value cell of the entire bunch, likely even out performing some of the "premium" brands.


The Bad

LingsFire  $11/pair    3600mAh    44g

Test Result: Cell #1 - 1.17Ah    Cell #2 - 1.93Ah    33-54% stated capacity

Inconsistent and uninspiring performance, plus they're hideous.  I'm done with them.


The Ugly

UltraFire  $8/pair    3000mAh    39g

Test Result: Cell #1 - 0.07Ah    Cell #2 - 0.10Ah

I figured they'd be losers, but not this bad.  Something is seriously wrong with these cells.  They're shorter, lighter, charge too quickly, and something about their construction made the magnetic leads (which works well on the other cells) repel the positive lead off the cell's button top, requiring that I come up with an alternative hook up for testing these.  The fact that, according to the web, there are likely dozens of different UltraFire manufacturers and retailers, some of which might actually produce good product, doesn't exactly inspire confidence for me.  I'm absolutely done with them!  And I'm really glad I charged and discharged these mutants outside on concrete, too.



I've got the CBA testing the first of the Eastshine cells, and it's looking like they'll beat the ThorFires, but not by much and at twice the price.  Details tomorrow.

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #8 on: January 04, 2016, 05:17:24 PM »
Thanks for the data!  I'm surprised there was so much spread from the Fire brands, I always assumed they'd come out of the same factory and thus, all performed the same.  Clearly that's what happens when you assume. ;)

...
After this test and also after reading yet another story about a flashlight blowing up because of a bad 18650 Ultrafire battery, I'm probably going to toss my Ultrafire RCR123s out of rotation and into SHTF usage only and buy a few more better quality cells.  I know the Olight batteries can be had for under $4 a piece, so if they measure up to the Nitecore, I'll get them, otherwise I'll get more of the $6 Nitecores.
I finally tested one of my Olight batteries.  Utter crap.  11:30 to full discharge from full charge.  The second worst performer overall.  Not at all worth it.  Not very scientific since I only tested one, but since I only own two, I know how they've been treated and that battery had less than 20 uses over the last three years and was always stored charged.  I still haven't pulled the other one since it's in a location I rarely remember to get to.

Offline Alan Georges

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #9 on: January 04, 2016, 05:32:29 PM »
Holy Cats, FreeLancer, that's a lot of testing!  Thanks for the data.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #10 on: January 04, 2016, 06:55:47 PM »
Holy Cats, FreeLancer, that's a lot of testing!  Thanks for the data.

The pleasure is all mine.  This is how I learn......by doing it, writing it down, sharing it with others, and then responding to criticism.  That's really why I choose to stay here at TSPF.


I should have at least 4 more brands to report on later tonight.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #11 on: January 05, 2016, 12:46:08 AM »
More 10W constant power tests on a good chunk of the "premium" brands.  These were all charged on the NiteCore D4 @ 375mA.


The Good

Eastshine  $30/pair    3500mAh    50g

Test Result: Cell #1 - 3.00Ah    Cell #2 - 2.97Ah    85% stated capacity    $5.03/Ah

This brand gets the prize for both best performance and the best value in the premium category, so far.  Only the Olights had a more perfectly matched voltage curve.  This is the cell to beat.


FoxNovo  $31/pair    3400mAh    49g

Test Result: Cell #1 - 2.91Ah    Cell #2 - 2.81Ah    84% stated capacity    $5.42/Ah

Much like the Eastshine in weight and dimensions, this brand turned in a slightly less impressive performance.  I was worried about the Eastshine and FoxNovo cells not fitting into some of my lights, but they do just fine.


The Bad

Olight  $36/pair    3400mAh    49g

Test Result: Cell #1 - 2.81Ah    Cell #2 - 2.82Ah    83% stated capacity    $6.39/Ah

While the tested capacity was below what I'd have expected at this price point, the two cells were perfectly matched on their discharge curves, the absolute tightest of any cells I've tested.  This cell is a loser because it's way too expensive.


The Ugly

EagleTac35  $40/pair    3500mAh    48g

Test Result: Cell #1 - 2.87Ah    Cell #2 - 2.93Ah    83% stated capacity    $6.90/Ah

This extremely disappointing performance, from the most expensive pair of cells out of the whole bunch, is deserving of the Ugly category.  The capacity wasn't horrible, but the voltage curves weren't as similar one would expect, and I expect superb performance at this price point.  This same brand's 3400mAh cells are charging now, we'll see how they test tomorrow.


ThruNite  $27/pair    3400mAh    48g

Test Result: Cell #1 - 2.57Ah    Cell #2 - 1.92Ah    66% stated capacity    $6.01/Ah

The absolute worst performance of the night.  This very well may turn out to be the UltraFire of the premium cells.  Given its weight and cost (plus the fact it's the only cell you can read the green Panasonic NCR 18650B markings through the outer shrink wrap), I had higher hopes for its performance.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #12 on: January 05, 2016, 01:09:41 AM »
ThorFire  $15/pair    3000mAh    48g

Test Result: Cell #1 - 2.46Ah    Cell #2 - 2.47Ah    82% stated capacity

The performance and consistency of these ThorFire cells deserves further attention.  I knew after weighing all the cells that these had much more in common with the premium cells than the "fire" crap, and the charge times added further to what the testing eventually proved.  These could very well turn out to be the value cell of the entire bunch, likely even out performing some of the "premium" brands.


I've got the CBA testing the first of the Eastshine cells, and it's looking like they'll beat the ThorFires, but not by much and at twice the price.  Details tomorrow.

Since I forgot to do it yesterday, I calculate $3.04/Ah for the ThorFires.  Compare that to the Eastshine's at $5.03/Ah.

endurance

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #13 on: January 05, 2016, 06:42:55 AM »
Great stuff. I'm looking forward to the final results. Since my goal is to get the most life out of a single cell for most applications, not necessarily the best value at a mid-grade, I suspect the overall winners are either in this bunch or the next. Having a cheaper 2.5a/h battery I have to change more often isn't as valuable as a 2.8+a/h battery I'll get a little more time with. Either way, the information you're presenting is great for making decisions on what to buy next.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #14 on: January 05, 2016, 07:45:22 AM »
Great stuff. I'm looking forward to the final results. Since my goal is to get the most life out of a single cell for most applications, not necessarily the best value at a mid-grade, I suspect the overall winners are either in this bunch or the next. Having a cheaper 2.5a/h battery I have to change more often isn't as valuable as a 2.8+a/h battery I'll get a little more time with. Either way, the information you're presenting is great for making decisions on what to buy next.

I need to calculate mAh/g on the winners.  I'm part way through testing my eight NiteCores and they're looking a lot like the Olights.
« Last Edit: January 05, 2016, 07:55:50 AM by FreeLancer »

Offline Smurf Hunter

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #15 on: January 05, 2016, 11:57:23 AM »
I have a bunch of random "fire" cells.  This is excellent data to have, as I have many 18650 lights around the house.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #16 on: January 05, 2016, 08:31:06 PM »
Same constant 10W discharge test as before, from full charge to 2.8V.  The NiteCores were charged on that same brand's D4 charger at 375mA.

NiteCore NL189  $37/pair    3400mAh    47g

Test Result: Cell #1 - 2.87Ah    Cell #2 - 2.78Ah    Cell #3 - 2.77Ah    Cell #4 - 2.76Ah    Cell #5 - 2.77Ah    Cell #6 - 2.77Ah    Cell #7 - 2.77Ah    Cell #8 - 2.81Ah    82% stated capacity    $6.64/Ah

I'm a little bummed about these results.  They cost a bit more than the Olights but do not perform as well.  Like the Olights, the NiteCore discharge curves are plastered one over the top of the other, so it appears that the company does an excellent job of ensuring consistency.  The first 4 cells are 11 months old, the rest are 6 months old, yet the performance is virtually identical.  Cell #1 had a curve that was identical to all the others, but stretched out that last little bit to get more capacity than the main pack.  Cell #7 had a voltage curve that was slightly below the rest, but then stretched enough at the end to finish with the same capacity as the rest of the pack.

While not as egregious as in the case of the EagTac35s, I do feel a bit ripped off by the $18+ NiteCores when compared to the Eastshine's performance, although most of my 8 cells were discounted by $2-3 by being purchased with either a NiteCore light or charger.  I think buying these cells as part of a bundle is really the only way it makes any sense.  They're certainly solid performers, but there's at least one brand that's better and significantly cheaper.  For me, all my 8 Nitecore cells will be staying in the Fenix TK75, as they're well matched to each other and provide a spectacular run-time in that configuration.

I'm very curious to see how the Orbtronics stack up against my benchmark NiteCores, as they're both cheaper and lighter, but seem to have a better web reputation.


TangsFire  $16 per 4 cells    3600mAh 

So....when this shipment arrived I was a little surprised to discover 4 LingsFire cells, not the TangsFire shown on my Amazon order.  All were exactly like the previous two LingsFires, so I decided to retest all 6 together, especially once I realized that the I'd stopped the previous Lingsfire's at 3V, instead of the the 2.8V.  Also, I mixed up cell one and two's data on the first test, so I'm just going to do it all over for all of them.  As far as price goes, the TangsFires were cheaper per cell than the LingsFires, but I have no way of knowing whether it was a mistake that I received these, instead of the Tangs, or what.  They both sound like something you'd catch in a Shanghai whorehouse and I'm not that interested in having either one to begin with, so I'm not going to pursue it further.

LingsFire  $4-6/cell    3600mAh    44g 

Test Result: Cell #1 - 2.13Ah    Cell #2 - 2.04Ah    Cell #3 - 2.07Ah    Cell #4 - 2.07Ah    Cell #5 - 2.15Ah    Cell #6 - 1.98Ah    58% stated capacity    $2.26/Ah

After tripling the sample size, the performance of these turned out to be more consistent than I was expecting.  Not great, but probably not a horrible choice for the money, either.  For this test, I charged all of them in my FoxNovo charger at 500mA, but then topped them all off for about 20 min prior to testing on my XTAR VP2 at 250mA.  Maybe that made a difference, but with changing the termination voltage from 3.0 to 2.8, in addition to the charging method, it's hard to differentiate.  But I'm curious and will be testing the better cells on the XTAR to see if their performance changes in relation to the D4 charger's results.


I'm running the EagleTac 3400s now, then the Simon and Orbtronics tomorrow.  Very, very curious to see how the Orbs do.
« Last Edit: January 05, 2016, 08:49:04 PM by FreeLancer »

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #17 on: January 06, 2016, 11:08:20 AM »
The Simon and Orbtronics are not not disappointing, but too early to tell which is superior and whether the extra cost over the heavier Eastshines is justified.  Can't wait to get home and finish testing.

endurance

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #18 on: January 06, 2016, 02:03:09 PM »
The Simon and Orbtronics are not not disappointing, but too early to tell which is superior and whether the extra cost over the heavier Eastshines is justified.  Can't wait to get home and finish testing.
You are such a geek.   ;)

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #19 on: January 06, 2016, 02:36:55 PM »
You are such a geek.   ;)

Takes one to know one.  ;)

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #20 on: January 06, 2016, 09:09:09 PM »
Final round of 10W testing. 

These were all charged on the NiteCore D4, but then topped off on the XTAR VP2 right before testing, like I did with the LingsFires.  This may make a difference and I'm probably going to top off the NiteCores the same way and run them all again to see if their capacity improves compared to the previous testing, where they were charged on the D4 alone.  This may lead to more testing to see if there's a difference in capacity based on the chargers and charge current settings.


EagleTac34  $38/pair    3400mAh    47g

Test Result: Cell #1 - 2.74Ah    Cell #2 - 2.90Ah    83% stated capacity    $6.74/Ah

Another disappointment from this brand.  Like the 3500mAh version, there's not much consistency between these cells discharge curves.  Both the Olight and Nitecore cells are much more consistent, have nearly the same capacity, and are cheaper.  Unless these are discounted as part of a bundled deal, I wouldn't get them.


Simon  $35/pair    3400mAh    47g

Test Result: Cell #1 - 2.99Ah    Cell #2 - 3.01Ah    88% stated capacity    $5.83/Ah

This is the top performer!  And they're not the most expensive, or the heaviest.  These cells look identical to the Orbtronics (but 1g heavier and a few bucks more), or at least they did until last night, when the Amazon picture changed on the cells coming into stock on Jan. 11.  I hope the change in the shrink-wrap doesn't correspond with a decrease in performance, because this is a great product.


Orbtronic  $63 per 4 cells    3400mAh    46g

Test Result: Cell #1 - 2.98Ah    Cell #2 - 2.91Ah    Cell #3 - 2.93Ah    Cell #4 - 2.96Ah    87% stated capacity    $5.35/Ah

This was a very close race, but the Orbs lose to the higher priced Simons and the lower priced Eastshines.  The discharge curves are not quite as consistent as the more expensive Simons, Olights, or NiteCores.  For those wanting to maximize performance to weight, the Orbtronic is the cell to get, as it performs at the top of the heap and only the LingsFire and UltraFires weigh less. 


My Interpretation and Recommendations:

If you're looking for the absolute longest run times, the top three are Simon, Eastshine, and Orbtronic, which are all capable of getting really close to 3Ah (equivalent to 1 hour) of run-time at 10W.  All three cost less than the other premium cells and only the ThruNites are cheaper than Eastshine.  However, the Eastshine is the heaviest and slightly bulkier than all but the FoxNovos. 

Olight, FoxNovo, and NiteCore are solid performers, but they're not the best or the least expensive of the premiums cells and probably not worth getting unless discounted when bundled with another product. 

I wouldn't waste much time looking at the EagTacs, the most expensive of the premiums, or the ThruNites, the least expensive.  Both performed inconsistently and there are better performers for less money.

Definitely stay away from UltraFire, at any price.  There's something really wrong with them and they have no business being considered alongside any of the other cells.  LingsFire turned out to be better than I initially thought, but not nearly as good as the ThorFires, and both are probably a reasonable value buy.


The big unknown, to my mind, is what the expected lifespan and durability of these cells is.  This might be reason enough to spend a bit more on one of the brands that has a longer reputation, but who knows? 

I do know that there is good consensus on higher charge currents being detrimental to the life of cells, but I don't know what the optimum current is.  It takes about 8-9 hours to charge the top performers in this group on the D4 at 375mA, so you definitely need to plan ahead, like the day before, if you want to avoid hitting the button for 500 or 1000mA currents.  Biggest bottle neck for this testing scheme was the charging, believe it or not, and that's with using a combination of three chargers for a total of 10 slots.  Kind of thinking an 8 slot charger could come in handy for some situations.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #21 on: January 07, 2016, 12:11:04 AM »
WTF?!

The first Nitecore just blew 2.95Ah, up from 2.87, after an XTAR 250mA top off between the D4 and the CBA.  Can one charger make that much difference over another?

If the pattern continues to show marked improvement, there's a bunch of other cells that deserve a retest with the same top off:  Nitecore, Olight, Eastshine, Foxnovo, both EagTacs, and Thorfire.  Both the Simon and Orbtronic cells already got that treatment.

What do you bet the Eastshines really shine, now?

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #22 on: January 07, 2016, 04:59:06 AM »
I guess I must be a geek if I'm still up messing around with these 18650s.  I'm seeing a 0.1Ah improvement in the overall average capacity, after topping them off on the XTAR, with just a couple cells left to test. 

I admit, I bought the XTAR VP2 because of it's ability to use an 18650 cell for USB charging purposes and was kind of disappointed when I found out that only the left slot was available for that purpose, so it wasn't possible to use two cells as a USB charger.  However, looking more closely at the online reviews tonight, it sounds like this is a very highly regarded Li-ion charger.  After watching some YouTube reviews, I went and pulled a Sony 18650VT cell, from my second bad Makita pack I harvested over the weekend, out of the discard pile and slipped it into the VP2 to see if it could wake the dead.  And, believe it or not, it's taken that cell from 0.59V up to 1.33V, when all my other chargers rejected it as a bad cell.

If anyone's looking for a superb 2 slot charger for 18650s, the VP2 is probably worth the extra money over a Nitecore.  It's made me a believer tonight and now I'm considering whether I should get the VP4 for increased capacity.

The other thing I like about this one is the ease with which you can slip a cell out after it's charged without disturbing the other cells.  They actually designed in enough finger space, unlike my Foxnovo and Nitecore.

Offline Carl

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #23 on: January 07, 2016, 06:09:59 AM »
You really don't want a multi cell USB type charger that uses parallel cells as not all batteries are the same and the differences can lead to a real surprise while charging or discharging some day....these things can burst into flames if not properly balanced.

Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #24 on: January 07, 2016, 08:57:00 AM »
You really don't want a multi cell USB type charger that uses parallel cells as not all batteries are the same and the differences can lead to a real surprise while charging or discharging some day....these things can burst into flames if not properly balanced.

That's the thing that scares the crap out of me about this stuff, the ever looming specter of bursting into flames because I do something stupid. 

Wait, I thought parallel was the safe route?  And how hard would it be to build chargers with appropriate balancing safeguards for multicell USB charging?

Offline Smurf Hunter

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #25 on: January 07, 2016, 12:17:00 PM »
That's the thing that scares the crap out of me about this stuff, the ever looming specter of bursting into flames because I do something stupid. 

Wait, I thought parallel was the safe route?  And how hard would it be to build chargers with appropriate balancing safeguards for multicell USB charging?

I think two different things are getting confused here.

Here's a premium example of a unit that can charge different types of cells simultaneously




Offline FreeLancer

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #26 on: January 07, 2016, 12:57:42 PM »
I think Carl's talking about the VP2's ability to be used as a power source for USB charging, where a single 18650 cell powers a 1A USB port when no power input cable is plugged into the charger, allowing a cell to be used to charge a phone or other device.  I had hoped it would be able to use both slots for this purpose, but it is only wired in to one slot, making it really no more effective than the much smaller Klarus Ch-1 that I posted a picture of on the other thread yesterday.

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #27 on: January 07, 2016, 04:16:13 PM »
This is a table of the above data, with Excel calculations in place of my brain/iPhone, which I believe are correct and inline with what I've posted previously. 



I ran standard deviations and found that the smaller results indeed correspond to my visual analysis of the tightest cell-to-cell voltage curves.  There's also a new power/weight calculation and I sorted the rows by best average cell output. 

I'll throw up another table with the revised numbers after I've obtained the post XTAR VP2 250mA top off charge results.  The preliminary data is kind of a mixed bag, with none showing the same degree of consistent improvement seen with the Nitecores.

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #28 on: January 07, 2016, 04:30:13 PM »
What I was mostly stating was that caution must be exercised when using multiple lithium ion cells in series or parallel.

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Re: 18650 Lithium Cell Recommendations: The good, the bad, and the ugly
« Reply #29 on: January 07, 2016, 06:07:02 PM »
In addition to the D4 that Smurf posted a picture of above, these are the other two chargers I'm using, for those that do better with pictures, like me.


Foxnovo F-4S



XTAR VP2