# Confused: Need 'Protected' or is Panasonic NCR18650 OK?



## Bolster (Apr 25, 2011)

I'm confused. I've purchased a Zebralight H60w that takes an 18650 cell, now I'm battery shopping. Do I _really_ need protected batteries?

The H60 has over-discharging protection built in, and will cut off the battery connection when the voltage drops below 2.8V. (This, according to the manufacturer). 

The 4sevens charger has a termination voltage built in (selectable @ 4.2V). 

So given that the light takes care of overdischarge, and the charger takes care of overcharge, do I still need a protected cell? 

Zebralight has told me the max length usable in this light is <68mm and: "We use flat top Panasonic NCR18650 cells without protection in our manufacturing (testing, QC, etc.)" I've researched this Panasonic cell and see it's a 2900 mAh with max length is 65.2, width 18.6. 

The reason I'm asking is, I understand this light has a tight fit with a lot of protected batteries. If I go protected, my options are somewhat limited, although the AW2200 looks like it would work, it's one of the shorter ones at 67mm in length and 18.3 in diameter.

But, it looks like any protected option available to me will reduce mAh by a fair amount. So I'm wondering if shopping for protected is like wearing a belt AND suspenders. Is protected worth the hassle, in my case?


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## rich297 (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

The 2.8 volt cut-off of the light is too low. By the time your cell draws down to that output, cell damage is likely to occur. You shouldn't rely soley on the charger to terminate charging of LiCo cells at 4.2 volts if charging a LiCo cell. In the interests of safety you should use a protected cell for redundancy. An alternative to the black-label AW cell, which has a protection circuit would be an AW 18650 IMR cell. It uses the safer LiMn chemistry and thus has no protection circuit. Consequently it is slightly shorter in length than most if not all protected cells.


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## HKJ (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



rich297 said:


> The 2.8 volt cut-off of the light is too low. By the time your cell draws down to that output, cell damage is likely to occur.



A protection build into a cell is likely to be around 2.5 to 2.8 volt.


It is generally a good idea to get batteries with protection, this way you have a double safety and you will also have some safety if you later uses the battery in another light.


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## Bolster (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

HKJ, looking at your excellent review of popular 18650s, looks like I'm down to AW1600 (the IMRs, but that's pretty low mAh!), AW2200, and *maybe* AW2600. The AW2600 is 67.5mm (that's less than 68--barely) and it's 18.5 in diameter, which is about the same as the Panasonic that Zebralight uses (18.6 max). Also the Tenergy 2600. 

Regarding cutoff, I noticed that Panasonic says that they stop the discharge of their non-protected at 2.5V for testing. So I figured that the Zebralight's 2.8V cutoff gave a little leeway. 

But I'm seeing a strong recommendation to get protected cells anyway...even at the expense of mAh.


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## VegasF6 (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

The Panasonic is a slightly different make up than other cells. The data sheet states "NNP series 2.5V per cell (2.75V per cell in the case of 2 series or more)."
Also, by the time the cell reaches 3V under load it really won't be able to deliver the current and should be very noticable to you.

At WORST, you may experience reduced life cycle of the cell due to over discharge, though I doubt it. The dangers are greater when used with multi-cell lights. And, the shunts that build up inside an overly discharged battery happen at much lower voltages. And over time. So, if you do run the light to the point where it shuts off at 2.8V (under load) and it bounces back up to a resting voltage of probably ~3.0 - 3.2V simply charge it again as soon as reasonably convenient. I would not be concerned for your safety in the least.

At the other end of the spectrum, while charging, as long as reasonable care is taken I see no concerns either. You can charge that Panasonic cell as high as 4.35V and suffer reduced life cycles, or you can choose to charge it to only 4.1V and greatly increase it's life. Most of us are trained 4.2V is the perfect voltage. Is it really? No. There is no such thing. 
The danger comes in when a mostly full battery receives a constant trickle charge over a period of time that can cause internal plating and dangerous failure inside the cell. 
Use a quality charger, check your voltages coming off the charger to get a feel for it, put the back of your hand on the cells while charging. If you feel any heat, unplug it immediately.

The final thing a protection circuit does is protect the cell from short circuits and high current draws and reverse polarity hookups. Since you won't have the circuit, try and be especially careful of these things. We are all taught not to trust these circuits anyhow, or at least, not to tempt fate.

Sorry if I am going against the norm here.


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## Glock27 (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

I don't use protected cells for single cell lights. All protected have a potential hazard that un-protected cells don't.....a positive strip on the outside of the cell with just a thin strip of insulation between both the negative cell wall and negative body of the light. 
I've ran lots of cells to cut off in Zebralights with no apparent cell damage. 
G27


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## HKJ (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Any unprotected cell will be short enough, they are 65 mm long and maybe 1 mm extra for a button top.

Generally it is no problem to discharge to 2.8 volt, when running at high brightness, only if you are running at low.

I believe that Panasonic are very safe cells, even without protection circuit, but one deep discharge and you have lost the cell!


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## alpg88 (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



Bolster said:


> Do I _really_ need protected batteries?



no, you don't.


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## Bolster (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

OK, now I'm headed back to unprotected...maybe unprotected Panasonics are the way to go. Use what the manufacturer uses.


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## alpg88 (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

any cell will be ok, even cheap no name cell, they will all work, just some longer, hey Panasonics are very good cells, so are the sanyo, lg. smasung.
i use unprotected cells for years, in lights that have low v cut off, not once i had any problem.


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## Bolster (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Since it's a headlamp, and will be next to my brain and eyes, I'm trying to approach this issue carefully. I've read the Li-Ion horror stories.


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## alpg88 (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

so did i, funny some of those exploded cells are protected, and 1 was not even rechargable, lol, and other time signs of battery problem were noticed before explosion, yet it was still used.
you got more chance of cheap protected cell blow up, than good quality unprotected.

cells blow up from shorts, and reverse charging, being it 1 cell light it wont reverse charge, shorts are possible, could be light malfunctioning (never seen it happen, or read of it happen), or could be protection circuit itself, it could happen on any protected cell, but cell with no pcb, and metall strips runing on the side, has less chance of it fail.


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## Bolster (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Found this interesting thread...which makes the point in places that a quality unprotected is safer than a cheap protected.

http://www.candlepowerforums.com/vb/showthread.php?212415-Panasonic-18650

Unfortunately it appears the conversation was terminated, due to nationality being peripherally involved in the discussion.


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## Bolster (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

This is interesting - someone in another thread says: "If you charge a non protected cell in a Pila charger, expect 6 cycles or less. There also is the possibility of fire." 

So if I get Panasonic unprotecteds, I can't charge with a Pila charger? 

Can that be true?


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## HKJ (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



Bolster said:


> Can that be true?



No.


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## Glock27 (Apr 25, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

I have a couple of Pila chargers. I have charged unprotected cells hundreds and hundreds of times and the cells are still going strong. I haven't logged how many cycles, but I'd guess some of my cells have 300+. I harvested them from a Dell 51510 battery pack. They come off the Pila @ 4.19. Stay above 4.16 for weeks. Run an SC60 for 1 hour 40 minutes on high before cut off.

G27


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## Bolster (Apr 26, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

I purchased two Panasonic NCR18650 unprotected cells today (65mm length, 2900 mAh), deciding to pin my hopes on the manufacturer's recommendation. I have the nagging feeling I purchased something dangerous. I don't have a charger yet. 

It's very confusing to read that Pila chargers will start fires with unprotected cells, when the author is a moderator and a level 4 supporter with over 10K posts. I'm a novice, so I'm in no position to judge the veracity. See post 7 here, where the author states the Pila shuts off at 4.6V, relying on the battery's built in protection to shut off at 4.2V. That seems illogical to me, but what do I know. 

The following post by another big-count poster confirms: "If you are talking about charging an unprotected cell in the Pila charger, don't bother. It *will* overcharge the cell." No following post contradicts these two statements. 

But then contradictory evidence found here, where the Pila is said to terminate at 4.20V.

So I'm left scratching my head, wondering what charger to buy. The Pila is universally recommended here on CPF.

I don't want to build a forehead bomb. I just want to use an H60w in peace and harmony with the electrons that fuel it. Who would have thought it would be so complicated and fraught with peril...or at least, REPORTED peril, whether real or not.

I'll admit I'm still pretty darned confused.


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## HKJ (Apr 26, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



Bolster said:


> It's very confusing to read that Pila chargers will start fires with unprotected cells, when the author is a moderator and a level 4 supporter with over 10K posts. I'm a novice, so I'm in no position to judge the veracity. See post 7 here, where the author states the Pila shuts off at 4.6V, relying on the battery's built in protection to shut off at 4.2V. That seems illogical to me, but what do I know.



Look at the date of that post, Pila has long ago revised the charger.


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## Bolster (Apr 26, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Whew! OK, that makes things much better. Thank you. 

Note to self: Buy new, not used.


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## Glock27 (Apr 26, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Both of my Pilas cut off at 4.2. I've had them for 2 years.

I too was scared to death when I jumped on the LI-Ion bandwagon. I have yet to have any problems.

Make sure you have a good volt meter. Compare readings from a couple different ones as I had one that was consistently .2 volts low....which is a huge difference for Li-Ion.

G27


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## Bolster (Apr 26, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

VOM, check. 

Here's an interesting attribute I found by reading Panasonic's tech sheets, regarding the unprotected NCR18650: 

"Increasing energy density raises the risk of overheating and igniting due to short-circuiting. Panasonic employs a heat resistance layer technology to improve the safety of LiIon batteries significantly. This heat resistance layer consists of an insulating metal oxide on the surface of the electrodes *which leads the battery not to overheat even if a short-circuit occurs*." 

Well! If that's true, now I can check off: 

- unlikely to overcharge with new manufacture Pila;
- unlikely to over-discharge with built in H60 circuitry (says Zebralight);
- no reverse charging due to one-cell light;
- reverse polarity protection built into the H60 (says Zebralight);
- unlikely to V.W.F. if short circuited (says Panasonic).

I'm feeling a little better about going unprotected now. I think I have most of the safety bases covered. 

So to summarize what I've learned here: 

- Don't use on lowest modes when battery is getting empty, or check occasionally that it still fires in high modes. 
- Any indication of low battery, stop and recharge right away.
- Use quality charger (current manufacture Pila a good choice)
- Feel the cell for overheating while charging. 
- Attend to the cells while charging, no "charging on their own next to where the gasoline is stored."
- Test the cell with VOM when charged, look for 4.2V or less.
- Triple-check the battery's going in the correct way on reinsertion. (EDIT: Will do this anyway, but have since learned the flashlight has reverse polarity protection built in.)
- Won't use my unprotecteds in series, one at a time in single cell lights only. 
- Keep unused cells above 3.8V during storage. 

How am I doing as a student? Thanks for all your help.


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## Brian10962001 (Apr 27, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Bolster, I really don't want to give you false confidence and I would feel bad if you got hurt/property damage taking my advice, but I'm still going to share my story with Panasonic cells. My girlfriend and her sister both bought Dell laptops around 2003/2004. My girlfriends Dell had the notorious "exploding battery" that would get so hot you could't have it on your lap. Her sister's battery just went bad from abuse/neglect. 

I repaired the sisters laptop a couple months back and purchased her a new battery. The old battery wouldn't charge at all, it would throw up the blinking "battery failure" light whenever it was plugged up. I popped it open and inside were the Panasonic cells you speak of. 

I left these sit these sit for a few weeks then out of curiosity I checked them with a volt meter. All of them were well below 2.7 volts, but one of them was at .9 volts. I ended up borrowing an 18650 cheapo cradle charger from a friend of mine, plugged it into an extension cord, and charged them in a frying pan. I honestly expected them to just explode in a firey deathly catastrophy. Every single cell charged right up, never got hot, never hurt a thing. I charged all of these up to a "too high" 4.25 volts and have been using them since. I upgraded from a cheapo cradle trickle charger to a modded Samsung phone charger that does the proper charging protocol for LiIon's. 

My advice is to not be scared, just take precautions ")


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## Microa (Apr 27, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

As my understanding, the Panasonic NCR-series was introduced in early 2010. You are talking an apple for an orange.


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## Bolster (Apr 27, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Thanks for the report, Brian. The H60 headlamp was introduced early 2009, if I recall, and Zebralight states that the NCR18650 Panasonics are the battery they used in their "manufacturing, testing, QC, etc." On the other hand, the spec sheet I have for NCR18650s is dated February 2010.

Either way, I think the point of the story remains the same: It appears the Panasonic makes a good quality cell.

Regarding being careful...I'll do my best...is there anything I should be doing above and beyond the bottom (purple) list I made in post #21?


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## jirik_cz (Apr 27, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



Microa said:


> As my understanding, the Panasonic NCR-series was introduced in early 2010. You are talking an apple for an orange.



Panasonic NCR18650 series was introduced in 2006. Panasonic NCR18650A with 3100mAh capacity has been in mass production since December 2009. I own some NCR18650 2900mAh cells since march 2009 and they are still as good as new. I accidentally discharged one of them to 0.9V and it didn't take any damage. These cells are just superb...


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## Glock27 (Apr 27, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Where can you find Panasonic NCR18650A batteries?
G27


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## Bolster (Apr 27, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



Glock27 said:


> Where can you find Panasonic NCR18650A batteries?
> G27



Hong Kong via eBay. $11.50 each, shipping included. Have not received them yet, just ordered a couple days ago.

Happy to learn about the 3100 mAh (the NCR18650A), have not found these for sale.


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## Microa (Apr 28, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

I hope you bought the genuine and brand new one. Look at their advertising photo, there are four wielding spots on the positive contact. A brand new battery don't have these.


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## Bolster (Apr 28, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Don't know. Looked through the last 1,000 of his feedback (of 13,804) and found one wrong-item-shipped complaint that was resolved, and one complaint he was out of stock. I'm not seeing people complaining of bait-and-switch or remanufactured cells. When the cells arrive I'll take a photo for examination by the forum. Thanks for the alert.

Can anyone verify Microa's statement?


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## psychbeat (Apr 28, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

hmm yeah
I was thinking of buying some of those too
but was going to start a thread asking which
vendor people were using for the NCRs

I may just buy more AWs but was feeling kinda cheap...


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## Bolster (Apr 28, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

May as well wait till I get mine and can give a report.


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## hazna (Apr 29, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



Bolster said:


> Don't know. Looked through the last 1,000 of his feedback (of 13,804) and found one wrong-item-shipped complaint that was resolved, and one complaint he was out of stock. I'm not seeing people complaining of bait-and-switch or remanufactured cells. When the cells arrive I'll take a photo for examination by the forum. Thanks for the alert.
> 
> Can anyone verify Microa's statement?


 
i don't know how this turned out but one person seemed to have some issues with hkequipment panasonic 18650:
http://www.candlepowerforums.com/vb...-6-*-18650-2900-mah-batteries-are-they-faulty


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## Bolster (Apr 29, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Interesting thread here by a former ebay seller of these cells. I see they recommend 5 charge/discharge cycles before they're ready for max capacity, which was more-or-less the same conclusion arrived at by the link Hazna gave us.


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## Microa (Apr 29, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Dear Glock 27,
You can find the NCR18650A here www.evvatech.com/sdp/1015379/4/pd-4967686/8389727-1953415/Lithium_ion_battery_Panasonic_NCR18650A_3100mAh.html


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## hazna (Apr 29, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



Microa said:


> Dear Glock 27,
> You can find the NCR18650A here www.evvatech.com/sdp/1015379/4/pd-4967686/8389727-1953415/Lithium_ion_battery_Panasonic_NCR18650A_3100mAh.html


 
Those 3100mah NCR18650A, do you know what the recommended terminating voltage is? I believe some higher capacity cells recommend a higher terminating voltage. Also I note minimum order is 100...


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## Microa (Apr 29, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

I don't have an offical data sheet. The data showed by the seller is terminated at 4.2V. Panasonic is rather conservative, may be terminated at 4.3V with no damage.


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## Mikl1984 (Apr 30, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



hazna said:


> Those 3100mah NCR18650A, do you know what the recommended terminating voltage is?


4.2V NCR-18650A
http://industrial.panasonic.com/www-data/pdf/ACA4000/ACA4000PE1.pdf
http://industrial.panasonic.com/www-data/pdf/ACA4000/ACA4000PE4.pdf


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## Bolster (May 4, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*



Microa said:


> I hope you bought the genuine and brand new one. Look at their advertising photo, there are four wielding spots on the positive contact. A brand new battery don't have these.



My eBay via HK Panasonic cells arrived today, well packaged, no "welding spots." They look like the real deal as shown toward the bottom here. Arrived at 3.66 V each. Currently charging on Pila charger. 







There's a dot matrix code written at the bottom of the cells. Might be a manufacturing date if I knew how to decode it.


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## moderator007 (May 4, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Looks like the real deal to me to.Want know for sure until you test them. Could you run a few capacity test and report back. I'm interested in purchasing some of these also.


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## Bolster (May 4, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

When you guys said "warm, not hot, during charging" how warm is warm? I can leave my hands on them for 5- 6 seconds, but then my fingers tell me it's time to go.


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## moderator007 (May 4, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

What type of charger are you using and what is your charging current?


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## Bolster (May 4, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

New Pila IBC 2-bay, looks to be...which one of these numbers?..."IBC Charger DC out 4.2 VDC / 600mA x2"

I've stopped the charging after 2 hours...until I can research how warm/hot is normal. Up to 4.04V now (no load). 

As I mentioned, you can press your hand firmly on the cells for 5-6 seconds before you want to take your hand away. Not to hot to hold in your hand but beyond 'warm.'


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## Glock27 (May 4, 2011)

*Re: Confused: Need 'Protected' 18650 if Light Cuts at 2.8V?*

Mine just gets "luke warm". I'd guess 100F. I'll try and find my infra red thermometer.
I have one cell charging for over an hour and it's 88.5F. The charger is 95F at it's hottest point right in the middle.
That sounds too hot.

G27


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## Bolster (May 4, 2011)

OK, so now what? I'm dead in the water until I figure this out.


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## moderator007 (May 4, 2011)

Have you read the voltage after taking them off the charger. Never had any get over warm to the touch draining or charging.


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## al93535 (May 4, 2011)

Using two unprotected cells in series in my light doesn't seem unsafe. I would watch the output and stop using it when the light begins to show any sign of reduced output. Use the same two cells together, always, and charge them together.


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## Glock27 (May 4, 2011)

I'd take them off the charger for a while and let them cool.
What voltage are they at now?
I just have one cell in my charger atm. It's a harvested laptop cell ~2200mah
G27


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## Bolster (May 4, 2011)

OK, from the top. All voltages measured with no load. I took notes during charging so assume times are accurate w/in 5 or 10 minutes. 
Cells arrive in the mail, 3.66V each. 
Start charging 6 pm in new Pila IBC charger. 
By 6:30 pm I note I can rest my fingers on the cells (with moderate pressure) for 5-6 seconds before needing to remove. 
By 8:00 pm 5-6 seconds isn't pleasant. Unplug the charger. Take voltage at 4.04V each. 
Research CPF frantically. 
8:30 pm, cells are room temperature, voltage now 4.03V each.

According to the Pila IBC thread, this means I took the cells from between "empty for all practical purposes" / "20% charge" up to 80% charge in 2 hours. The charger paperwork says "normal recharging time is around 3.5 hours." Remember stage 3 is a slow charge. Don't know when it kicks in.

I'm freaking out a little. Should I start a new thread asking about this specific topic?


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## Glock27 (May 4, 2011)

I put another discharged cell in and the temp. is rising. 105F tray between the cells. 94F cell temp.

G27


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## Bolster (May 5, 2011)

I don't have a good way to measure. I've read a couple of places that you can scald yourself in 5 seconds in water of 140 degrees. Since I was touching/pressing for 5-6 seconds with no damage or burn feeling, just the desire to move fingers away, I'm going to guess 120-130 degrees. Just a ballpark. Immersion would be more intense than touching, so it's hard to calibrate. Maybe 140 is closer. 

I'm brand-new to 18650s. So where does this leave me? Does a 2900 mAh get hotter than lower mAh? Toss the cells? Return the charger? Keep both? Normal? Abnormal? Proceed? Stop? Take up a different hobby? Currently charging has been halted until I can get some clarity.

Two NIB H60w's waiting.


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## Glock27 (May 5, 2011)

If they were mine....If they were cooled off, Id charge them some more. If they get hot to the touch (I can hold on to mine indefinitely), Id take them back off the charger and start another thread under the "Hot Cells" sub forum.
Perhaps this is normal for larger capacity cells. Remember that the Pila charge time is probably for ~2,200 mah cells.

G27

P.S. I always take the cells out of the charger before un-plugging. Don't know if this would make any difference.


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## Glock27 (May 5, 2011)

If you can get the cells to 4.20, I think the self discharge rate will tell you a lot about the health of the cells.
G


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## mvyrmnd (May 5, 2011)

I have these exact same cells. They're my favourite 

I charge them in a WF-188, and they've never been more than 1-2 degrees C over ambient.

Your Pila is charging them at 600mA. The WF-188 charges at 650mA. I have no idea why yours would be getting so hot. Sorry I can't be of more help, but I promise you that this isn't normal for these cells.

In your shoes I'd buy a different (cheap, if you want) 18650 and charge it to see if it gets as hot. If they don't, it'll be the cells. If they do, it's the charger.


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## VegasF6 (May 5, 2011)

No, that isn't normal. And the capacity of the cells wouldn't make any difference in temperature. I agree that you should probably start a new thread with this in the title, in the smoke and fire area. 

I have to lean towards it being an issue with the cells. Which is a real bummer. Luckily you werent anywhere near hot enough to be in the danger zone, but you are right to be concerned.


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## Bolster (May 5, 2011)

*OK, thanks. New thread started here, all are welcome.*

Currently trying to figure out how to test the charger directly so I can rule it out as a suspect.

EDIT: Pila IBC charger was charging at 670 mA, not 600 as stated.


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