You hear it all the time: Don’t use ANYTHING but protected Li-Ion batteries. And while they certainly have their place, do they necessarily have to be the ONLY battery you should use for ALL applications? As an example, most good quality single cell lights already have low voltage protection built into the light. And decent chargers won’t overcharge your batteries. If you use a decent charger and use the batteries in single cell lights that already have built-in protection, why shouldn’t unprotected batteries be used? It would seem that using protected batteries is just going to cause fitment headaches and possibly even mechanical damage due to excessive force being placed on electronic components (should the tailspring bind and cause the full force of tightening the tailcap to be transmitted though the battery).
if you are careful, and know what you are doing, it´s ok, or even mandatory in some applications to use unprotected batteries. But it’s a good advice for some people to use protected only
All my 18650’s are laptop pulls and thus are unprotected. I’m very careful about the voltage about my cells.
That being said, protected 18650 cells are highly recommended to those who are new to li-ion technology.
I know a Jetbeam DDR30 that had a shorted capacitor, and that shorted the inputs to the 3x li-ions in series. Had they not been protected, the batteries would have killed themselves, not to mention melting away the springs and heating up dangerously.
Unprotected work fine most of the time, but when there is an error, then you will be glad you were using protected batteries. Most good lights I see are designed for the bigger protected cells - the protected will fit properly while unprotected will be loose and rattle.
Protected batteries is are for who does not have the time/ nor want to check health of batteries regularly. If you have a random charger that you got for cheap or use a wrong charger, the protection will melt itself or cut the circuit to stop the flow from accidental over charge. Another thing is when you accidentally short a battery or leave something on by accident, it will completely drain the battery. When Li ion goes below 2v for over a week, it is dead and dangerous if used again. If you charge this battery and use it in series with other battery, reverse charge can happen and your flashlight could turn into a pipe bomb. Protection is pretty much never necessary if used as by iteself and not in series or parallel with any other batteries. I shorted a full charged 18650 from a laptop and it did not vent, it only got very hot. The only thing that i know you definitely need protection if possible is Li Polymer batteries. They are not sturdy like the 18650’s they are mostly flat and have alot of surface area to expand. Enough heat/over charge could get these things to pop. I hope everything I said is correct. If something is wrong PLEASE, someone correct me.
Simple safety tips:
-Buy cheap digital multimeter (DMM) and measure voltage before you charge each battery to make sure it wasnt sitting at under 2v, or 2.5v to be safe. And test battery if it is over 4.35V (best voltage is 4.2 but inaccuracy of DMM could be way off) to see if you have a bad charger.
-Make sure your charger is a SMART CHARGER. 4 stages. Pre/CC/CV/Cut
This is NOT a smart charger: It acts like one but it is missing the CUT and real CC.
-When charging batteries, make sure the top side of the batteries are not pointed near any flammable objects. just incase if it vents, the hot gas would not be able to light anything.
Handy in a non low voltage cut-off light too I would assume.
The only protected cells I have are in a 2x series light I never use. I hate the fact it can shut off without any notice.
A quick visual glance when changing batteries looking for loose parts that could short, like loose driver springs foreign bodies etc.
Unprotected for Direct Drive or 7135 linear drivers.
Protected for Boost or Buck drivers is what I’ve heard.
I’ve been using unprotected sanyo/panasonic cells with a Xtar charger, and flashlights with Linear drivers for 3~years without the slightest problem. I do occasionally check fresh off the charger voltage for peace of mind.
Recharging when starting to dim (3-3.2v) or after prolonged use, life’s too short to be trying to prolong battery life by careful usage. The oldest batteries I have still hold a real good charge, all this don’t ‘discharge below such and such a voltage and always keep them in the fridge’ is too anal for me. Just use them and get newer and better if they wear out.