Li-ion Battery Safety and Shopping Guide

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scaru
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NightCrawl wrote:

And you got the APR18650M1 twice. Smile

I'm aware, I put it in there twice because I wanted it under IMR (since it does such high currents) and under LiFePo4. I understand this is not technically correct since it is not LiMn cell, so maybe I should remove it from the IMR section?

NightCrawl
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Technically speaking, the CGR18650CH isnt LiMn either..^^

But I would keep LiFePo4 cells out of the LiIon lineup, those are too special and only very few people actually use them.

Btw.: what about 32650, 26650, 26500, 22650, 18500, 17650, 16650, 14650, 10440, 10180? (yes, I'm here to molest you)

Oh, and where did you get the graph of the Sanyo UR18650W? I ordered W2 and WX recently, waiting for them to be tested..

Shadowww
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scaru wrote:

I’m aware, I put it in there twice because I wanted it under IMR (since it does such high currents) and under LiFePo4. I understand this is not technically correct since it is not LiMn cell, so maybe I should remove it from the IMR section?

Yup, it doesn’t belongs in IMR section.
scaru
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NightCrawl wrote:

Technically speaking, the CGR18650CH isnt LiMn either..^^

But I would keep LiFePo4 cells out of the LiIon lineup, those are too special and only very few people actually use them.

Btw.: what about 32650, 26650, 26500, 22650, 18500, 17650, 16650, 14650, 10440, 10180? (yes, I'm here to molest you)

Oh, and where did you get the graph of the Sanyo UR18650W? I ordered W2 and WX recently, waiting for them to be tested..

True, but I feel it should be there. I guess I'm sorting by function not strictly chemistry. I'll leave the LiFePo4 batteries in for the smaller batteries at least because some lights can take a 3.3v battery but not a 4.2 volt battery. 16650, 18500, and 10440 will be added later today when I get a chance. 32650, 26650, and 32600 will be added at some point in my 3rd comment which is for bigger cells. 

The graph actually came from the datasheet (which I did link to already Wink), which is here. 

http://www.master-instruments.com.au/data_sheets/UR18650W.pdf

scaru
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Shadowww wrote:
scaru wrote:

I'm aware, I put it in there twice because I wanted it under IMR (since it does such high currents) and under LiFePo4. I understand this is not technically correct since it is not LiMn cell, so maybe I should remove it from the IMR section?

Yup, it doesn't belongs in IMR section.

Ok, if both of you think that it is getting removed now. Smile

ruffles
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Thanks — nice work… very useful.

On the subject of XXXfires, maybe it’s worth mentioning the lifecycle of a fake:
- laptop/recycling pull (or worse, as we’ve seen little lipos wrapped in 18mm tubes)
- new shrink wrap from taobao (http://budgetlightforum.com/node/14962 — even shows Panasonic wrappers at http://item.taobao.com/item.htm?spm=a1z10.3.0.77.saBKb5&id=10193523421& )
- off to ebay (or a semi-reputable vendor that’s being cheated)
- and into some unsuspecting flashlight


 

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Scaru, if you continue to excel in this manner, you will have to "drop the diaper", and start wearing long pants.

Keep up the good work!!Wink

My PayPal address: oldlumens (insert the @ sign here) gmail.com

My YouTube Flashlight Video Channel

The BLF Modding Links Thread 

http://imageshack.com/a/img922/1374/jQ2wdL.jpg

 

nqcken
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begging for a spreadsheet…. i know some do not have excel but open office is free and i think it would solve a lot of organizational problems. my apology if there is a spreadsheet in here somewhere i just could not wade thru it all

ken

scaru
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I have excel, what would you like in the spreadsheet?

scaru
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Ok, done with the smaller batteries. Tomorrow I will tackle the larger batteries. 

scaru
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Done with 26650, after all 2 in the morning is tomorrow. Silly

scaru
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32650 and 26500 will be added tomorrow. If anyone has any further suggestions post here or PM me. Also, if someone can clarify what is wanted in a spreadsheet that would be appreciated. 

Shadowww
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Why is Keeppower 16650 “Unspecified internal cell”? It uses the same UR16650ZT as Intl-Outdoor 16650. Silly

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Choosing batteries: Scaru, could you please point out to beginner purchasers that that there are three main types of contact points on the positive end. Flat, button and nipple. The “button” term can be misleading, because its generally used to describe both button and nipple. Some flashlights with reverse polarity protection such as Eagletac, require nipple tops. A nipple top has a smaller diameter button than a true button top and is usually raised up a little more.
It is good to double check when purchasing, because photos of button tops sometimes make them appear to be smaller in diameter and result in awaiting a new battery only to find it will not work without the aid of a magnet.

…safety and use of magnets?

scaru
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Ouchyfoot wrote:
Choosing batteries: Scaru, could you please point out to beginner purchasers that that there are three main types of contact points on the positive end. Flat, button and nipple. The "button" term can be misleading, because its generally used to describe both button and nipple. Some flashlights with reverse polarity protection such as Eagletac, require nipple tops. A nipple top has a smaller diameter button than a true button top and is usually raised up a little more. It is good to double check when purchasing, because photos of button tops sometimes make them appear to be smaller in diameter and result in awaiting a new battery only to find it will not work without the aid of a magnet. ...safety and use of magnets?
I will add info on that today, Smile

Shadowww wrote:
Why is Keeppower 16650 "Unspecified internal cell"? It uses the same UR16650ZT as Intl-Outdoor 16650. :P

Oops, I knew that. Silly As always, thanks for keeping me honest. Wink

scaru
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Ok, done with the larger cell section unless anyone has any requests. I added this info about button tops and magnets. 

"There are 3 main types of positive contacts used on the batteries. First, and most common is flat top; these are a simple metal contact no higher than the surrounding label. This is the way batteries generally come from the manufacturer. (Does not apply to NCR18650 series) Then there is raised top, or button top, this has the same contact size as the previous one, but the whole surface is raised. This is needed in lights where the batteries are stacked to ensure contact. Then there is nipple top, this has a small raised top; much smaller. Some lights that have mechanical reverse-polarity protection require nipple tops. 

People often use small round magnets to create a a nipple top from a flat top. To do this one simply places a magnet on the top of the battery, this does come with a risk. The magnet can easily slide out of space and short out the battery, it is for this reason people often place a dab of superglue under the magnet. An example of one of these magnets is this. "

And I'll ask one last time, what would you guys like in a spreadsheet?

scaru
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Ok, one last bump before I remove the "In Progress" label. Shadowww come over here and tell me what I screwed up. Wink

Shadowww
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scaru wrote:

Ok, one last bump before I remove the “In Progress” label. Shadowww come over here and tell me what I screwed up. Wink


I’m afraid you’ll need HKJ for that Silly
scaru
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Shadowww wrote:
scaru wrote:

Ok, one last bump before I remove the "In Progress" label. Shadowww come over here and tell me what I screwed up. Wink

I'm afraid you'll need HKJ for that :P

Yay, I got the shadowww seal of approval. Wink

scaru
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Ok, this one is done! And at 44 pages it is my longest article yet. Smile

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Thanks for the work Scaru.

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What are the temperatures Lion batteries should be used in?

I’m mainly interested in what is considered safe and normal for the 18650 cells while charging and discharging them, what temperature raise in these conditions is tolerable.

What are typical internal resistances of different Lion cells?
18650s, 26650s

When are they good, when bad?

Got this yesterday from some other place:

Resistance Condition
  1. - 150 mOhm
Excellent
151 – 250 mOhm Good
251 – 350 mOhm Marginal
351 – Up mOhm Bad

My 18650s raise by 4-5°C while charging at 0.5-1.0A, they are old Sony US18650GR cells, testing them and so far it seems they may have 1700-2000mAh from the stock 2400mAh and have internal resistance around 30mOhm. I find them not very good. Higher drain and charge rates are a no go for them I think. They lasted 5-10min in my laptop. Slow charge and discharge (0.5A) seems ok though and causes no heat up and capacity seems usable as well. I suspect they may be getting overcharged, right now it shows 4.19V when pulled out of the charger, while in charger and charging the voltage shows 4.24V and charger shows 4.1V and balance shows also 4.1V. Still charging them 0.3A. My DMM is not calibrated and I can’t figure out a way to get something that I could calibrate it to.

I’m trying to test all 6 cells and determine their capacity. Should I be worried about them raising their temperature +5°C? What about +10°C? The cells don’t go over 35°C.

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Awesome work!

Has someone ever thought of a BLF FAQ or wiki? I think it wouldn’t be a bad thing Wink

~ carpe noctem ~

scaru
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JackCY wrote:
What are the temperatures Lion batteries should be used in? 

Generally between 20 and 40 degrees Celsius for maximum capacity. 

JackCY wrote:
I'm mainly interested in what temperature raise while charging and discharging is considered safe and normal for the 18650 cells. What are typical internal resistances of different Lion cells? 18650s, 26650s When are they good, when bad? 

The raise in temperature is due to the increased internal resistance. It causes some of the energy used to charge the battery to be lost as heat. One can find the internal resistance of a cell from HKJ's tests. For example the NCR18650B has a .11 ohm internal resistance. Most LiCo cells have a internal resistance ranging from 9 to 20 mohms. 

JackCY wrote:
My 18650s raise by 4-5°C while charging at 0.5-1.0A, they are old Sony cells, testing them and so far it seems they may have 1700-2000mAh from the stock 2400mAh and have internal resistance around 30mOhm. I find them not very good. 

30 mohms is definitely more than a good cell would have but is still usable, just not at high currents. 

JackCY wrote:
Higher drain and charge rates are a no go for them. They lasted 5-10min in my laptop. Slow charge and discharge (0.5A) seems ok though and causes no heat up and capacity seems usable as well. I suspect they may be getting overcharged, right now it shows 4.19V when pulled out of the charger, while in charger and charging the voltage shows 4.24V and charger shows 4.1V and balance shows also 4.1V. Still charging them 0.3A. My DMM is not calibrated and I can't figure out a way to get something that I could calibrate it to.

It makes sense that they cannot handle high drains as the increased internal resistance means that less current would flow. What charger are you using?

scaru
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AlexHH wrote:
Awesome work! Has someone ever thought of a BLF FAQ or wiki? I think it wouldn't be a bad thing ;)

There is a wiki, no forum associated with it though. 

http://flashlightwiki.com/

I've started to write my own articles for BLF, but it is hard to compete with flashlightwiki. In total the three of my articles are something like 100 pages. Surprised

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scaru wrote:

The raise in temperature is due to the increased internal resistance. It causes some of the energy used to charge the battery to be lost as heat. One can find the internal resistance of a cell from HKJ’s tests. For example the NCR18650B has a .11 ohm internal resistance. Most LiCo cells have a internal resistance ranging from 9 to 20 mohms. 


Ah, good. I saw his numbers but didn’t know what is the normal range.
.11 = 110mOhm, that’s pretty high. All his numbers are 10 times higher so it seems like all 18650s there are around 90-150mOhm. Maybe he missed a 0? But probably my charger can’t test it properly.
On my Lipo pack, it reads 4-6mOhm on two cells and on the 3rd one 12mOhm, on a pack that is supposed to be manufacturer matched and below 3 mOhm. (40C constant, 80C burst, 10C charge)
Quote:

30 mohms is definitely more than a good cell would have but is still usable, just not at high currents. 

What would high currents be?
For 30mOhm? Or is it in the end 300mOhm? How could I measure it using a resistor and DMM or something? Not to rely on my charger’s resistance measurement.

1A, 300mOhm 0.3W, yes that will be heating up
1A, 30mOhm 0.03W, not sure that could make a 5°C difference
Quote:
It makes sense that they cannot handle high drains as the increased internal resistance means that less current would flow. What charger are you using?

Turnigy Accucel 6, edition with an internal resistance meter.
18650 battery holder, it’s 1 cell but I made a connection to the balancer port on the charger as well. Allows me to do the internal resistance test and to see the voltage measured by the balancer. It seems to measure different voltage when charging, the total voltage of the battery and the cell on the charger. Even if it is just this 1 cell battery. Might be 0.05-0.1 difference, it does stop both on 4.1V when charging in Lion mode. DMM reads 4.24V, when battery pulled out it reads 4.19V.
As I read here Lion batteries are also charged to 4.2V as Lipo? Dunno why does it have two modes, Lion and Lipo then, Lipo is 4.2V/3.0V, Lion is 4.1V/2.9V (charge/discharge).
I suppose it charges the Lions in Lion mode to 4.2V but then they naturally drop to 4.1V?

The internal resistance always depends on the state of charge and use of the battery. It reads higher sometimes. I’ve measured all 6 at 28-31mOhm when they were sitting on the shelf at storage 3.67V-3.77V, two were 4.00-4.15V as I’ve charged them full before.

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Thank you Skaru for giving of your own time to put all this information together for newcomers like myself to read. People like Yourself help to make this Hobby Fun and Safe for all.
Cheers
Chris

Damn Addictions

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After looking at this and other sources, I still don’t know if the cheap 14500 cells I bought are safe or not, let alone what to expect from them. They are blue with stenciled numbers like most of those I see on Amazon. They say “GTL Li-ion 14500 1200 mAh 3.7V”. I think I paid 3 or 4 $ for the pair. They work but may not be as bright as reviews I read about lights with similar cells.

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。

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Wow, nice post, very useful for new members.

I’d perhaps suggest mentioning that some people aren’t so happy with the i4 charger even if you still like it. Overcharging and high temps are of concern for some. Check out the awesome thermal shots in some of the charger threads, the i4 looks dangerous!

The section saying that a Sanyo UR18650FM gives longer runtime on a 7135 (~3V LVD) versus the Panasonics is incorrect. I’m not sure where this common misconception comes from, HKJs graph shows its wrong and just try it out Wink The Sanyo may maintain a higher output nearer the end of its capacity but it will trip low voltage protection noticeably sooner than the Panasonics.

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Thanks Scaru

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