Educate me on 18650 batteries

Status
Not open for further replies.
Quattro Pete

Quattro Pete

Joined
Oct 30, 2002
Messages
42,371
Location
Great Lakes
I'm a newbie to this. Is there a good website that you can link me to that describes the differences between various types of 18650 batteries? Protected, unprotected, flat top, etc.? Quick google search didn't work for me this time.

Also, are there any decent budget brands worth considering, say EBL? Or should I stick with Panasonic and pay the hefty premium?

My applications are flashlights. No vaping and such. One of the flashlights I recently bought came with a battery that looks like below. Is that considered a "flat top"? Not sure how to tell if it's protected or not. I would like to buy more like this one...

IMG_20161130_104126.jpg


IMG_20161130_104216.jpg


Thanks!
 
That is button top; NOT flat top. It does NOT look like protected if it does not state that explicitly.

Samsung or Panasonic or Sanyo
Accept nothing else.

If your flashlight takes multiple cells, always stay with the protected cells.
 
Last edited:
First inform yoyrself of the energetic release capability of oxide-cathode li-ion, even if just small 18650 cells.

There are a variety of cathode materials, each having a sweet spot in charge/discharge/cycle life/safety, etc. some newer variantsare no longer just hraphite on the anode. There are 3-4 typical commodity cathode materials in use, then iron phosphate, which is much safer from a cathode perspective but also lower voltage so lower energy density.

Protection is generally a vent (for cylindrical cells, the case is scored to open at some overpressure, sometimes a mechanical vent that opens the conduction path, and sometimes a positive thermal coefficient safety device to intereupt.

There is lots more info - what else do you want to know?
 
The 18650 cell displayed is protected, you can see the bottom plate is the bottom plate of the protection circuit. Also I'd consider it as a "flat" button top (lol), flat top cells have positive top really recessed.

There's only a limited number of cell suppliers (good quality suppliers!), as stated above, Panasonic/Sanyo, LG, and Samsung, that's all.

But there's many company that took cells from Panasonic or others, add a protection circuit, and sell them under their own brand. To cite a few good one, AW, Eagletac, Keeppower, etc... and all the rebadge, Olight, Klarus, Xtar, etc. They differ in their size (adding a protection circuit increase the length and diameter, some brands claim smaller cells like Eagletac and AW), quality of the protection, threshold of the circuit (max current, lowest voltage, etc)...

Keep in mind max capacity for a 18650 is around 3500-3600mAh stated, real capacity around 3300/3400mAh max. You also have different cells, depending on the max discharge current you want. There's multiple references...could you state the flashlight you are using so we could give you more precise direction?

Edit: if you like flashlights (like I do, lol), take a peak at candlepower forums, and also budgetlight forums. Lots of great and friendly people there.
 
Last edited:
Most of your flat tops are for building battery packs. Same with unprotected ones. If you are buying cells in a commercialish type of package ment for end users they most likely are going to be button top protected cells.
 
Also here is a direct link to some good flashlight batteries.


https://www.amazon.com/KeepPower-3400mAh-protected-Panasonic-NCR18650B/dp/B00LSFNDXC

https://www.amazon.com/dp/B00CAD6AUE?psc=1


I would not recommend any battery brand that has the word "FIRE" in it. BRANDS TO AVOID...Ultrafire, trustfire, etc.

Be very careful here are a lot of bad batteries on the market on ebay and amazon that are basically un protected recycled laptop batteries that are sold as protected and with random wrappers and capacities on them.

Anything stating to be over about 3600 mah is a fake, some are labeled 4000 mah, 5000 mah, or even 9900 mah!, but those are fakes, the highest capacity quality cells are about 3600 mah until they squeeze more power out of such a small space and even then we are talking about incremental gains of 50-100 mah each generation.

Here is a quick slideshow of what can be out there
 
Slightly OT, but to emphasize the importance of buying name-brand quality batteries...
A few years ago, my house nearly caught fire while the family was out of town.
Son had left a flashlight on his dresser loaded with no-name CR123's (I purchased those, not knowing about the dangers of non-protected and cheapo Li-ion batteries at the time).
Had enlisted a neighborhood kid to come in the house daily to care for the house cat.
One day the neighbor walks in to smoke in the house. He tracks source to son's room. A battery had apparently exploded, knocking the flashlight to the carpeted floor. There was ~12" carpet burn clean thru to the concrete slab (typical construction for Louisiana homes). The carpet was still smoldering. Kid calls for his dad to come over. They doused the area with water and made absolutely sure the fire was out, then called me. Scared the hek out of me!
Lesson learned: saving a few $$ in battery purchases nearly cost me my entire home!
 
Originally Posted By: 901Memphis
Originally Posted By: thescreensavers
Check out this link , guy tested many batteries.

http://lygte-info.dk/review/batteries2012/Common18650comparator.php


Hey this the same site I linked up in the thread, I guess other people know about it by now I thought it was a hidden secret



haha it is I was on mobile so didnt scroll though alll the posts, its a great link
laugh.gif
ive had it book marked for over a year or so now, not really sure where I found it hah.
 
I ripped open an old laptop battery and took out all the 18650 batteries. 1 or 2 wouldn't charge but the rest are good for a $20 flashlight.
 
Only 18650s I have are Orbtronics 3500 mAh wich is basically a Panasonic protected re-wrap. Never a problem... yet.
I used to visit candlepower forum for battery & flashligh info, after buying to many flashlights and batteries, I been staying off to curb the buying urge.
 
Originally Posted By: Leo99
I ripped open an old laptop battery and took out all the 18650 batteries. 1 or 2 wouldn't charge but the rest are good for a $20 flashlight.


With legitimate protection circuits you will prevent over discharge of the battery. In some flashlights they have no protection built in and you can take a laptop cell down past the point of no return where you destroy the capacity due to the chemistry of the battery, usually around 3 volts, since it will be fully discharged around 3.5-3.7v

Also the protection circuit helps as a redundancy if the charger over charges because thermal runaway happens fast with these cells and they will explode if over charged
 
looks like a sanyo/panasonic ga with protection.
anker tends to rate things properly and the rating on that cell is what i get from a ga.
beware of anything over 3600.its fake!and no rewrapper sells the panasonic 18650g.
most that sell the ga rate them at 3500.you wont get this at real world drain rates.kudos for anker rating them properly!
stay away from any fire brands,ebl,gtf (should be gtfo),ect.
and stay away from amazon,ebay.
mountain electronics,illumination supply,lion wholesale are good places to buy stuff.
Originally Posted By: Quattro Pete
I'm a newbie to this. Is there a good website that you can link me to that describes the differences between various types of 18650 batteries? Protected, unprotected, flat top, etc.? Quick google search didn't work for me this time.

Also, are there any decent budget brands worth considering, say EBL? Or should I stick with Panasonic and pay the hefty premium?

My applications are flashlights. No vaping and such. One of the flashlights I recently bought came with a battery that looks like below. Is that considered a "flat top"? Not sure how to tell if it's protected or not. I would like to buy more like this one...

IMG_20161130_104126.jpg


IMG_20161130_104216.jpg


Thanks!
 
Status
Not open for further replies.

Similar threads

Brons2
School me on foreign property ownership, from a USA perspective
Replies
13
Views
855
cptbarkey
S
new battery is smaller than OEM
Replies
14
Views
3K
Carmudgeon
A
Flickering dash at idle, did not start after I shut it off, battery voltage 12.7 when off. Is alternator fine?
Replies
13
Views
1K
mk378
Graham Piccinini
2003 Lexus GS300
2
Replies
39
Views
3K
Graham Piccinini
john_pifer
I Got On a Flashlight Kick
2 3 4
Replies
67
Views
9K
zmelli
Back
Top