18650 - Are protected batteries ALWAYS better?

For use in single cell applications,are protected batteries ALWAYS better,or are there some situations where unprotected batteries might be more practical? Do protected batteries have limitations regarding charging and discharging which might hinder field work,trickle charging etc?

Hi Dave, I think your question has been asked and answered in a myriad of ways, but always great to hear from our educated and enlightened (ha!) members. I'm neither of those but I can get things started.
Short answer is "no" protected are not always better. They have a protection circuit which is another thing that can go wrong. They may trip out and leave you in the dark. Protected are longer and often wider and can present a fitment issue.
My take on it is that you should use only high quality batteries and keep track of their usage and charge them on a high-quality charger.

I know,with days of reading 10 pages per question for 10 hours for 10 days I might get close to understanding and still not have an answer.

Basically I'm worried that when I'm out in the bush,with no mains power and trying to charge batteries with solar panels or the usb charger that plugs into my car cigarette lighter I'd be better off with unprotected batteries,but I tried to form the question so that the answers would be more useful to the general newbie community for later reference

Pros and cons of either protected or not. The pcb is for over and under discharging so for example it may trip at 2.5v and 4.25v. Most single cell(multi to) lights these days have some kind of safety cut off or warning. Be it flashing light, loss of higher modes etc. To get a cell down to 3v which is above manufacturers minimum V take some doing tbh......

Many prefer protected cells in multi cell lights that may run in series. Depending on the user their choice could be either type of cell. I prefer unprotected in single and multi cell lights, higher drain cells basically.

Regardless of protected or not, practice should be the same which is not deep discharging the cells regularly . This can shorter the life of the cell/s over time. Learn the light, check the V at set times to get an idea of the voltage used between charges . For example you may use medium for 5hrs over a week. The voltage may be 3.6v and so you know you can charge the cell up weekly. Or you may simply prefer to top it up after each use , or every other day......

Protected are a few mm longer , some lights they can be a tight fit! Same with some carriers ,but of a squeeze to get the 70mm cells in. The unprotected may be 66mm long and fit a lot easier and may sway your choice. The savings per cell of unprotected might too.......Protected also have a slight drain due to the pcb and it's also something else to fail for some people ,who need to limit failures due to their actual use.

So no IMO protected are not better, depending on the application they have their advantages but that's it for me. If the user is dependable on the pcb to tell them the cell is low by tripping, then the chemistry is wrong for them .

Just as important as good cells from reputable shop/seller is the charger! One that works to spec and terminates to spec without trickle charging .

There really is no art or requirement for a degree , just a read up , an understanding , common sense and ideally a tool to measure the voltage away from the charger to aid fault finding and simply to have another form of measuring the V. Lot of good chargers have a V readout, might be enough for some.

Limitations wise, too much amp can trip the pcb (2 ways of looking at it as tripping due to too much current is also a good thing). So some lights protected cells are not a good option. Also if a strip down the side ,its susceptible to shorting if damaged .

Regarding choice of which to go for would depend on what light ,what type of use . From this I would make a decision on which type of cell.

Thats a a brief take on it from me, not saying I am right, just the way I look at it.

Typed on an iPhone so god knows what *beep* it's changed !!

I don't know much about the cells.. I always go with unprotected battery. Since most of my light are modified. I can also use unprotected cells in stock light too if I need it..

fivemega said:

If current draw is more than what protected cell can provide, unprotected or IMR cells will serve better but if that current draw is within safe operation, using unprotected cell is unnecessary.

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Unless, as with the Zebralight SC600-III, protected cells simply will not fit.
I'd say it highly depends on the light and charger used and the application.
Generally speaking I would recommend protected cells for lights that support them, or following the manufacturer's recommendations.

As for protected cells, it depends on several factors, such as battery low voltage cutoff (most DIY LED flashlight drivers already have Li-ion battery protection in form of software - they shut down at around 2.8 Volts - some stock LED flashlights also have similar firmware in the SOIC-8 packaged microcontrollers - be it ATTiny or PIC16) and overcharge cut-off, that's where decent charger comes in - I have Foursevens single bay smart charger for almost three years, no problem with it so far.

You can put in protected call in some flashlight, providing they fit in the battery body (tube) - the driver won't care about up to 200 millivolts drop across circuit breaker MOSFET. One more problem, is that they add up to 3 mm in length due to the protective plastic cap at bottom of Li-ion battery containing protection PCB. I usually run unprotected Li-ion batteries anyhow as they don't go over 3 Amps in my flashlights (although one of my recent Nichia NVSW219CT neutral white flashlight might hit 3 - 4 Amps when in direct-drive mode on a freshly charged 3.3 Volts Lithium Iron Phosphate cell).

Wow. I didn't know LiFePO cells provide high current draw like that.

That depends on state of charge, of course; the higher voltage, the higher the current. It also depends on Vf. Cree LEDs suck in LiFePO4 cell compatible flashlight due to their generally higher Vf. So, Nichia NVSW219CT LED is definitely the LED to go with for 3.3 Volts batteries.

recDNA said:

Wow. I didn't know LiFePO cells provide high current draw like that.

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A123 Systems LiFePO4 18650s can provide a continuous 33A. Admittedly, though, with only 1100mAH of capacity, they won't do this for long.

As for the original question of protected vs unprotected batteries, I myself have never used protected batteries. Even in lights with series cells. Unprotected batteries are cheaper, smaller (especially shorter), and produce a higher voltage. People worry about safety. But if you use quality cells, quality chargers, store them in plastic cases, and use them in single cell lights with built-in overdischarge protection, there is absolutely NO safety disadvantage to using unprotected cells. In lights without overdischarge protection, safe use of unprotected cells is mainly a matter of knowing how long your light will run on a full charge and keeping it charged. Also, recognizing when your light starts to dim is VERY helpful in knowing when it is time to change batteries. With multi-cell lights, it's all about knowing your runtime. Low battery warnings can also help, especially if you use good quality cells that track voltage evenly from one cell to another.

Just spotted this on BangGood, this is the HKJ recomended single slot charger. "I have no affiliation with this seller"

LiitoKala Lii-100 0.5A/1A Li-ion Ni-MH USB Battery Charge

$3.80 48% OFF

http://www.banggood.com/LiitoKala-L...d=QLKeQnxox6&emst=QLKeQnxox6_24818_1867134_49

StorminMatt said:

A123 Systems LiFePO4 18650s can provide a continuous 33A. Admittedly, though, with only 1100mAH of capacity, they won't do this for long.

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Correct. However, 1.1 Amps / hour is good enough for my flashlight usage as I have two of A123 LiFePO4 cells, and there are multiple modes I can use (as far as ToyKeeper Bistro firmware in the hybrid FET - 7135 driver is concerned). It won't do on old school Halogen flashlight, however, even though it's a powerful cell.

Dr. Mario said:

It won't do on old school Halogen flashlight, however, even though it's a powerful cell.

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I would think that, with its dead-flat discharge curve, LiFePO4 would be IDEAL for incandescent flashlights.

It depends on the incandescent bulbs, of course. Some are quite puny, others just rape the batteries. However, I agree that LiFePO4 cell have rather flat discharge curve - I have noticed that when I played with my brand new DIY Nichia 219C LED flashlight (turbo mode has current of 1.4 Amps which is enough to get flashlight rather warm after ten minutes - it barely taper off in brightness).

To be honest, if someone is asking the protected vs unprotected question, then they should probably use protected.

Unless you use single cell in a powerful flashlight containing a microcontroller chip which has low voltage lockout, there's little point in using protected cell. I routinely run unprotected cells in my single cell flashlights I assembled. On the other hand, the protected cell do have its merits such as usage in the solar charger.

StorminMatt said:

I would think that, with its dead-flat discharge curve, LiFePO4 would be IDEAL for incandescent flashlights.

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Which has the disadvantage that you get almost no warning when the voltage abruptly drops from full to empty (same problem for cells with internal buck/boost converters). Cells with flat discharge curves require special fuel gauges that attempt to workaround this.

Protected batteries should be used always and whenever possible.

Big battery manufacturers are very clear about this.
Unprotected cells should not be used in any application without proper protection.

What some posters here did not mention is extremely important, and it is called SAFETY.
Protection is not there (especially on 18650, 26650, 14500....) for overcharge or over-discharge purpose only.
Main reason that should be always on the first place is Safety.

Short circuit is dangerous as hell, and should be prevented at all costs when working with li-ion.
That's why we are using Protected batteries.

Sony is already contacting sellers and asking them to stop selling unprotected Sony VTC batteries to vapers (obviously flashlight community will be "hurt" by this as well).
Next will be LG.

Everyone should watch this video and learn something from it.

https://youtu.be/xS8LsPv1_uM

Now, go ahead and put your unprotected cell in your pocket together with car keys and some metal coins.

Of course - don't do it

High quality protected 18650 battery is able to handle up to 10-12 Ams.
How many Amps one flashlight needs, 20A ?
I do not think so.