What do you mean by âunprotected 18650 cellsâ?
Pretty much all quality cells have internal protection devices except maybe those used by Tesla.
Those with an external PCB added to offset over discharge, under discharge and over current.
Itâs a common thing.
Chris
Hello
Cells â GAâs â ? Is it this one? :
Cellule Lithium 18650 3.6V SANYO GA 3500mAh
-If yes,i donât understand why it would be the best, explain to me please 
they only do : Discharge current: 10A
while the samsung 30Q : 15A
and better : the sony VTC6 : 30A
so for my flashlight ,the sony VTC6 would be the best?
thank you in advance for your reply
edit : this is for use in my flashligt sofirn q8
Yes, correct, those are the ones!
Also correct, although the 30Q can go higher maybe the VTC6 donât go to that limitâŚ
These two questions cannot be seen separated in you case. So: which is your flashlight?
Only knowing that we will be able to reply âwhich is the best for your flashlightâ.
Discharge capacity in not the only thing that needs to be taken into account when chosing a battery.
Example:
a) if you want a battery with larger capacity, youâll go for a Sanyo GA or a Samsung 35E. You can use this in the cases when your flashlight doesnât need a high discharge cell (ex: a light with a driver that only goes to a certain limit in draning).
b) if you want a battery for high discharge, youâll go for the Samsung 30Q or the VTC6. You will use these when you have the so-called âhot rodsâ, like Emisar D4 or something with FET drivers that will draw a high amount of Amps to achieve/deliver top power.
Hello,i read your link, thank you
i also found this interesting table :
link : Alternatives to Samsung 30Q
but i have the samsung 30Q since 2 years and they are already dead! they no longer charge at all
whereas i had read by google that the cells li-ion ones can on average be charged 300-500 times
i have recharged my samsung 30Q less than 100 times i can swear
but i may have discharged them too much : in general, once put in my charger they displayed about 2.70 mah ,what could be, with time, deteriorate them ?
Therefore i am very disappointed with the samsung 30q but the sony vtc6, according to my table,would be even worse ,their lifespan is even less good?
Battery life cycle also depends on other factors â like if itâs often left (for a somewhat long period of time, like several months) in a fully-charged state (staying at or near the full 4.20v without getting used at all), or in a very discharged state (like below maybe 2.5v or around that) â that appears to degrade the cells faster too.
Samsung 30Q has a big problem - high selfdischarge. Probability is increasing with utilization. Compare Samsung 30Q versus SONY VTC6 selfdischarge. Both cells are after the same cycle aging test.
Around how many cycles is the Samsung 30Q prior to it having a high-self-discharge?
Also, would you happen to have data for the new Samsung 30Q6-T (the newer variant/model that are manufactured in China)?
New 30Q cell at 100 % SOC shows little bit worse selfdischarge than other cells from the very beginning.
Probably is worsening gradually during using. The cells (30Q and VTC6) from comparative 72 hours test are after 700 cycles : charge 1A to 4,1 V, 0,1 A cut-off, discharge 2,5 A to 3,3 V.
Mooch´s accelerated life cycle test from gotlib´s link can be relevant for vaping maybe, but definitely not for flashlight. 4A charge and 15 A discharge are parameters to kill the cell early.
Have no data on the new 30Q6-T you mentioned.
Hello
thank you very much for your very precious information!
@docware thank you for your screenshot and graphic very interesting! 
so for my sofirn q8 you recommend me rather the sony vtc6 than the samsung 30q?
if so, would you know by chance where i can buy the cheap vtc6 shipped to France?
I definitely cannot recommend Samsung 30Q. There is too much info about 30Q high selfdischarge from various ebike forums.
In Europe is nkon https://eu.nkon.nl/ considered to be trustworthy supplier :
You just must accept that Sony products doesn´t belong to âcheapâ category.
thanks to you
Just made quick look at sofirn q8. You need button top version for q8 flashlight. My previous link was flat top.
i had already found it thanks,but they are out of stock until 09 February 2021
No no, out of stock is flat top version. But you need button top version which is in stock .
no ,add 4
then click on â add to cart â
and you will see the message above :
â The requested quantity for âSony / Murata Konion US18650VTC6 3000mAh - 30A button topâ is not available. â
theyâve been out of stock for several months, i donât know what theyâre doing,it annoys me and i wrote to them but no response from them
You have to be patient, your order is very small, therefore doesn´t have a priority.
no thatâs not it :
if you live in USA maybe you see them : available on their site
but me from France, they wrote well :
US18650VTC6 3000mAh - 30A button topâ is not available.
= out of stock
and i made a mistake :
i thought i read yesterday on their site that they would be available again on February 9 .Mut i was wrong :
it only concerns the â flat top â version
-For the button top they do not announce any availability date itâs worse than i thought! :weary:
Hmm, that´s bad.
I live in Europe, Czech republic.
You have an alternative option, LG HG2 button top. I checked that they are really in stock.
I recommend to use DPD for shipping, have wrong experiences with other options.
https://eu.nkon.nl/rechargeable/li-ion/18650-size/lg-18650-hg2-button.html