# 18650 Different Lengths?



## Sharkin (Sep 4, 2013)

I just recieved 2 Ultrafire 18650 batteries purchased off fleabay when I noticed they are a different length compared to the 18650 battery installed in my Hexbright light. I'm not a battery guy, but I thought they are supposed to be the same size or did I receive something different?

The length of the Ultrafires is 64.70mm while the 18650 in my Hexbright is 67.92.

Here's a pic:


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## DrafterDan (Sep 4, 2013)

It's hard to tell from that angle, but I'd bet the cell on the left is protected. That means there is a small circuit board with load limiting on it


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## mattheww50 (Sep 4, 2013)

Unprotected 18650 except the Panasonic 3400mAh cells are all very close to 65mm in length. Protected cells are another story. A small PCB is added to the cell to provide the protection circuit, and that adds anywhere from about 3 to 5 mm to the overall length. The extra length can be quite troublesome in some applications.


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## Sharkin (Sep 4, 2013)

thanks for the info.

i kind of flipped out when they wouldn't fit my light, but they are for a different project. i should be good to go...thanks again.


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## torukmakto4 (Sep 4, 2013)

Not sure where the myth of the oversize NCR18650B came from but it's not true:

http://industrial.panasonic.com/www-data/pdf2/ACI4000/ACI4000CE54.pdf

64.93mm. It's the same size as any other Panasonic 18650 and compliant with the 18650 standard. Sanyo actually has a larger upper limit for both diameter and length. The supposed "3400 Pana fitment problems" are all down to a rash of problems with third parties rewrapping this particular cell, another reason I don't like rewraps.

Also, OP you should consider yourself warned about the quality and most importantly safety of those UltraFire brand cells. Have a look in the Hot Cells forum and note the big glaring hint. The BRC18650 that you have is a common wrapper to be found on recovered junk pack pulls, extremely cheap crappy cells, and QC rejects. In one case even a fake cell with a tiny lipo inside wired to the terminals. You never know what you're gonna get with any variety of TrashFire products. If I were you I would head on over to fasttech and pick up a 2 pack of your favorite reputable 18650 (Sanyo, Pana, LG, Samsung et al.) for 6 to 15 bucks depending on brand and capacity.


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## fivemega (Sep 4, 2013)

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


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## yoyoman (Sep 5, 2013)

http://www.candlepowerforums.com/vb...Battery-test-review-summary&highlight=summary 

HKJ's summary includes a chart showing length.


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## HotWire (Sep 16, 2013)

RCR123 cells can vary in size as well. I have some Klarus and Trustfire cells that are so long they won't work in some of my lights! I'd like to see a standard size adopted by battery makers.


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## therock (Dec 8, 2014)

*Can 18650 Batteries Be Different Lengths?*

Can 18650 Batteries Be Different Lengths? Maybe as in protected and unprotected ones?

I purchased a Power Bank that is supposed to make use of a 18650 but I cannot get one of my flashlight Orbtronic 2900mAh protected batteries to go in. It almost fits but will not.

Would a protected unit be a little longer? I cannot tell if this power bank board has a protection chip.

Thanks,


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## Norm (Dec 8, 2014)

*Re: Can 18650 Batteries Be Different Lengths?*

I played with a few multicell power banks and all were made for unprotected cells. 

From HKJ's thread. 



> The 18650 specifications means that a cell is about 65 mm long, but protected batteries are longer, because a protection circuit must be added and sometimes there is also added a button top. Not all chargers and lights can take the longest cells.


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## therock (Dec 8, 2014)

*Re: Can 18650 Batteries Be Different Lengths?*

Thanks, Great info and link!


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## therock (Dec 8, 2014)

One more? Should I go with a High Drain? t will be for an emergency cell phone battery backup. LG Nexus 5.

Thanks


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## NoNotAgain (Dec 8, 2014)

therock said:


> One more? Should I go with a High Drain? t will be for an emergency cell phone battery backup. LG Nexus 5.
> 
> Thanks



A high drain cell is for items requiring 8 amps or more power. A cell phone ain't high drain.


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## therock (Dec 9, 2014)

As a FYI, I found data in 2 reviews: Everything one would want to know on the unit. I'm Happy Now  This should apply being posted here as it can be used to charge unprotected flashlight batteries?
Mine is black with white cover, it can be had from many vendors, some will let you choose colors.

*No.1 *This 1st one is a link to a review where a guy has a nice 5+minute video detailing this exact unit. He speeds it up when needed and provides data.

The Unboxing, and complaints in other reviews are addressed here such as the LED being hard to see in daylight, and the cover is hard to get off. He fixes them nicely.
He superimposed tech data here and there near the end. It's protected, supports pass through charging, its uses, and some numbers and such.

http://club.dx.com/reviews/248804/553556

*No.2 * 

Another Techie's short review.







Involvement:Expert (understands the inner workings) - Ownership:1 week to 1 month 
*Pros:*Plastic looks well machined, pieces snap together perfectly. Doesn't look cheap at all.
I could fit Lithium cells removed from an old laptop battery.
Managed to boot a Raspberry Pi with it and keep it running over 5 minutes (as headless server) 

*Cons:*Doesn't fit protected cells.
While charging, output voltage drops (don't know why) 

*Other Thoughts:*I will try to make a bypass, so it can work as a UPS for my Raspberry Pi 
*Bottomline:*Perfect for charging your cell phone, but since voltage drops while charging the bank, intended usage might not be possible


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## Gew (Sep 24, 2015)

*Re: Can 18650 Batteries Be Different Lengths?*



therock said:


> Can 18650 Batteries Be Different Lengths? Maybe as in protected and unprotected ones?
> 
> I purchased a Power Bank that is supposed to make use of a 18650 but I cannot get one of my flashlight Orbtronic 2900mAh protected batteries to go in. It almost fits but will not.
> 
> ...




I think I have bought exactly the same "DIY powerbank kit" as you, probably cheap from eBay, right? I also bought really cheap 18650 cells "Ultrafire" that was said to hold the somewhat unrealistic figure of >6000mAh a piece. Now, the old saying "What you pay is what you get" is indeed true, since these cells shown to be s*ck big time. A full charge took my Samsung Galaxy S4+ never further than 20% upwards and then it was totally drained. I later ordered another cell (this one) from a national e-store, which were a bit mot expensive, and told to hold 4200mAh. I picked it of the post office just yesterday. It felt somewhat more heavy than the old cheap Ultrafire battery, and when I put it in the power bank shell I noticed it was hard to fit in there. Ultimately, I got it in, but the plastic wrapping wouldn't, so I made an ugly solution by wrapping duct tape around the piece. 






Looks horrible, yeah I know. So, indeed, 18650 cells seem to be of various length. According to the e-store from where I bought this one, it's protected, and measures 67,8 mm from top to toe. It's diameter is 18,2 mm. According to Wikipedia, the 18650 is told to have the size 18.6 × 65.2 mm. However, it also states, quote, "Two different cells of the same nominal size, e.g. two 18650 cells, may have different diameter buttons if made by different manufacturers, and this can lead to incompatibility with devices", which is exactly spot-on here.

Cheers!


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## Phlogiston (Sep 25, 2015)

*Re: Can 18650 Batteries Be Different Lengths?*



Gew said:


> I later ordered another cell (this one) from a national e-store, which were a bit mot expensive, and told to hold 4200mAh.



There's no such thing as a 4200mAh 18650 on sale. The highest available capacity for an 18650 is 3600mAh (from Panasonic). I'd treat that cell with suspicion if I were you - it may not even have a protection circuit.


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## KeepingItLight (Sep 26, 2015)

*Re: Can 18650 Batteries Be Different Lengths?*



Sharkin said:


> I just recieved 2 Ultrafire 18650 batteries purchased off fleabay when I noticed they are a different length compared to the 18650 battery installed in my Hexbright light. I'm not a battery guy, but I thought they are supposed to be the same size or did I receive something different?
> 
> The length of the Ultrafires is 64.70mm while the 18650 in my Hexbright is 67.92.



I am a bit of a newbie myself when it comes to Li-ion rechargeables. 

One thing I have learned, however, is not to buy from random sellers on Ebay or Amazon. In the USA, *Illumn *and *Mountain Electronics *are two of the better-known online sellers (with good prices). You can buy with confidence at either one. In Europe, I have heard that *nkon . nl* is a reputable seller, but I do not have any experience with it.

Another thing I have learned is that any of the Li-ion brands with a name like xxxx-Fire, such as *UltraFire*, can be hit and miss. Sometimes you get the real thing, but many times you do not. Sometimes you get used batteries that have been pulled from old laptop battery packs. Often there is no protection, even when the label says a battery is protected. If an 18650 battery from one of those brands is labeled with a capacity above 3600mAh, it is already a miss. My opinion is not to bother with any of them. 

One final opinion I'll share is not to buy (or use) chargers that carry the xxxx-Fire name. *Xtar* and *Nitecore *make good quality chargers that sell for moderate prices. Pick up one of them. 

CPF member HKJ has performed extensive testing with most of the best-selling chargers and batteries. Read his reviews.

A good protected 18650 battery for most uses is the *Sanyo-Panasonic NCR18650GA Protected 3500mAh*, selling right now for $10.15 USD at Mountain Electronics.

_Late edit: _It looks like I have responded to the OP in a necro-thread that was recently reactivated. OP may not get to read it, but the advice still stands.


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