Ah yes, I bet this is the case. Makes sense. Although I have run my Eneloops to the ground on many occasions and they still work great. For me, the easiest solution is to simply keep a dumb NiMH-only charger handy just for this situation.
Thanks, I’m going to go check that out that batteryuniverity site.
Sorry to keep kicking the same old horse, but the guys who developed the technology for commercial use had a few things to say about it:
Lithium Ion Rechargeable Batteries
It’s not for the faint of heart! But you’ll notice they tested a lot of the failure modes we fear most, with surprising results.
(Of course, just because the battery itself in a test rig doesn’t do what most people claim, does not mean the other conductors in our flashlight circuits (such as that spring) can take its charge dumped through a short!!!)
Dang dude. Now I’m a bit scared to use my laptop pulls.
They could, but…
The problem is that all of that current must go through the transistors in the protection circuit. By the time they paralleled enough transistors for that kind of current the protection circuit could hardly fit on the end of the cell.
Edit: Not to mention all that heat generated on the bottom of the cell.
Laptop pulls are fairly safe as long as you monitor and follow the do’s and don’ts. Its important that you learn li-ion characteristics. They can be very harmful if not treated properly. I don’t mean to scare anyone into thinking they are unsafe. A incident is very rare, but they do and can happen as you will find here and all over various forums where they are used and discussed by members. Learn all you can about the do’s and don’ts, its important when using li-ions.
.
When I mod a new light the very first battery I stick in it to test with is a protected battery. If all goes well, then I try a good unprotected battery. You never know when something might be shorted out, until you test it first.
.
Its always a good practice to follow, when receiving any new charger or battery, no matter the brand or quality, to monitor its behavior for the first few charger’s. Its always possible to get a lemon. That lemon could cost you a lot if you don’t know it’s a lemon. Here’s one! My 14500 battery explosion, with pictures
.
I never leave my chargers when charging unattended. If for some odd reason the charger doesn’t terminate, or the cell starts building heat it can go into thermal runaway. Its better to be in the same room with you so you can have a chance to deal with the problem, than it is to be in a separate room where you might not notice the problem, until its to late.
.
Its no different than owning a gun, if don’t practice safety, you’ll end up shooting yourself in the foot. 
They could, there are a lot of suitable MOSFETs, not just the one everyone's using. But you have to order at least 10.000pcs and they would certainly be more expensive than about 1-2$. Thats why nobody does it (at least for flashlights, in power tools there are huge procetion circuits).
If a PCB doesnt kick in because the current is too low, its broken. The MCU doesnt care about the current draw. Also, 2.5V is harmless for Panasonic cells, but dont let a 4.35V cell get down that far.
I only use unprotected cells (except for those in my Sunwayman V10A). My drivers step down at 3V and my flashlights are built well (built by me ofc. :P).
Ya, but your a expert. :bigsmile:
Well in that case, have you heard anything about the quality (or lack thereof) of the XTAR 18700 protection circuit? That’s where I believe it happened to me.
I have never experienced the pcb not tripping with a low current discharge.
But I have also heard of it happening. No idea of the cause.
I have not seen a disassembled cell yet, but I doubt Xtar would invest in developing a PCB thats worse than whats already available. I wouldnt worry about that.
But aside from that, using the protection to turn off a flashlight or finish charging is a bad habit.. even if you have a PCB, dont rely on it. Its actually not there to do anything, its more like an airbag that you can use more than once, but you usally never use it. The risk is pretty low with NCR cells tho as those can be discharged to 2.5V without a problem. But you know how it goes.. there is some protection, people feel save and start being careless, protection fails, something goes wrong -> damn. Ever dropped your cell on the protection circuit? There is a good chance that the PCB is now broken.
If I had to buy protected cells, I would buy Enerpower. Only brand I really trust, because the owner (rutzki) is very open and communicative. Nitecore and Keeppower have spoilt me, I dont trust clear wrapper and Xtar.. build quality doesnt convince me. Efest and Eagletac had some nice ideas in the past but often use weak cells and claim untrue stuff. Efest IMR are fine though. Then there are AW cells, maybe I'd buy those, but its unknown what cells are inside the 2600mAh ones and they are very expensive in Germany. Too many secrets for me. ;)
So I checked out that website, pretty substantial amount of information there. Thanks!
Grrr, yes… never thought about that.
Ever dropped your flashlight with a cell in it? Good chance that the PCB is broken. :P
Its never good to drop LiIon cells.. but the bare cell is certainly more robust than the flimsy PCB. Any cheap driver is built like a tank compared to those PCBs.
Using a sacrificial Sony 2200 mAh laptop pull and $1.30 Protection Circuit Board for 3.6V. Discharging with an 8ohm resistor would trip the boards low voltage cutoff around 2.7 volt. However, I had mixed results using a light with no low voltage cutoff at lower current rate.
The board worked perfect for repeated direct shorts. No sparking or heating, just a clean disconnect until short removed. The over charge protection tripped out at 4.30 volts. The overcharge and low voltage necessitated the board being reset by charger to switch it back on, never the short.
Using my icharger, I could do a 4 amp discharge. I could have gone higher but battery not rated nor do any of my lights draw that amount.
I like the board mainly for the short protection. I would love to see these made cheap and programmable for a safer all around battery for general use.
OK, so now this begs the question: How can I tell if any of my cells have a broken PCB?
protected is safer, but unprotected is way more fun :party:
Testing, but if board is inoperative due to damage then lots of smoke or worse may happen. If in doubt you might quit using it or give it to Pulsar to test. (grin)
Ok so here’s my story on this topic (sorry if anyone saw my previous post on this). Packing in a hurry to go on vacation I threw my SRK with freshly charged PROTECTED NCR 18650B (clear wrapper from Fasttech) in my bag and forgot to lockout tail cap. Upon arrival I reached in my bag, and the light was warm. I immediately knew what had happened, and put the batteries on the charger I had brought, no-go. I tried several methods to un-trip the protection including, putting cells in parallel briefly, using wire to bring voltage from a fresh cell out of another light, and putting the tripped cells in a cheap charger that doesn’t care about starting voltage… nothing worked. As a last resort I cut-off the protection circuit boards and the cells still wouldn’t take a charge. Out of the 75 or so lithium batteries I own this was the ONLY time I have ever over-discharged any cell, and the protection did not work. I have since replaced those cells with Keeppower’s and will not use generic protected cells again. Strange, when I made the original post on this, not many people seemed interested.
…and you tested the Keeppower for low voltage cut off? My first SRK would get really hot after 20 minutes so inside a bag your lucky nothing else happened?