Hi,
Product description of Sanyo GA protected button top 18650 3450mah
- What is the meaning of having PCB tripped?
- What is the cause?
- Does this mean the battery is unrecoverable?
as written that sounds like a permanent useless battery
I think there are errors in translation
what follows is what I think it true of protection circuits in batteries
> What is the meaning of having PCB tripped?
it means the battery “fuse” has been tripped and it needs to be recharged. Some chargers have no problem resetting the fuse, and the battery will charge back up. Occasionally I hear of people who say their charger wont reset the protection circuit. I have not had that happen.
I can tell when a battery trips protection because the light suddently stops working, completely. And the battery will read 0 volts on my meter.
> What is the cause?
draining the battery below a certain voltage… about 2.7v under load
> Does this mean the battery is unrecoverable?
No, it means it will remain unuseable until it is recharged
however, based on the way that link is written, I would not buy that battery…
unless someone who has actually used it, can verify my opinion that it can be reset by recharging
This seems to be a reputable seller, recommended in this post, (the post said “He’s a member on BLF”)
It’s a store in Canada, a translation error is rather unlikely. I would hope that a protected battery would be safer than unprotected one. But it looks like a kind of one-time use battery.
Re-reading the product description, I see
So is that when PCB kicks in? And is this call tripping the PCB? What is “undercharge” BTW? A charger which is too weak?
Low Voltage Protection.
You either know or don't. If you don't, better don't fully rule out a possibility just because it seems unlikely or impossible to you (this is no license to start believing in stuff against your highest good, of course).
Plain wrong. That definition is more like that of the CID (current interrupt device) inside a cell, see Battery Safety 101: Anatomy - PTC vs PCB vs CID @ Battery Bro.
A cell protection circuit is a simple, built in battery management system. It consist of a battery protection integrated circuit (the DW01 is typical for single cell protection) which drives a few MOSFETs or dual MOSFETs (like 8205As and others) as a switch to control current flow to the battery. It servers as overcharge protection by limiting the absolute maximum charge voltage (overcharge protection), the allowable minimum cell voltage (overdischarge protection) and also protects the cell from excessive currents (short-circuit protection). A protection circuit, particularly in the case of small circuits like the ones built-in with cells, always take a toll at the cell's performance. Check, for example the following graph:
It is from HKJ's battery comparator, original tests performed on protected and unprotected NCR18650B cells in the old 2-terminal station. The difference between the red and the blue curves is the additional voltage drop caused by the dual 8205A MOSFETs in the protection circuit.
Particularly I don't use protected cells, I take great care of my batteries and flashlight drivers usually have all what is needed. In the case of simple unregulated MOSFET or linear drivers, the very minimum led Vf of white leds poses a hard limit to how deep the flashlight cell can be discharged, so no problem.
I believe that is another “loss in translation”, and would be what I call, overdischarge… that is, when the voltage of the battery gets too low, and there is risk of polarity reversal, and venting with flames upon recharge.
given you are just learning about LiIon, I think you should avoid lights that cannot use protected cells. Unless the light has built in Low Voltage Protection (dont assume the light has that feature unless specifically stated).
jon_slider, you can take a cheap white flashlight with linear or direct drive driver (an SK98, for example), insert an unprotected cell inside, turn it on and leave it that way for a few days. Since the very minimum led Vf is ≈2.4 - 2.5 V (besides voltage drops in driver and etc.), the cell won't go below that voltage. Tested by myself.
I had no knowledge about modern flashlight and Li-ion. Bought lights on eBay before I knew BLF forum. Now the headlamp has been delivered. I think it doesn’t have low voltage protection. Not even a warning LED to signal when voltage is low. The product description doesn’t mention anything about voltage protection.
Just tried it yesterday and the medium brightness mode is plentiful enough for my need. Because of the lack of low voltage protection, I wonder if this headlamp would run until it kills the batteries. I have no idea about the runtime of the provided 18650 cells ($2 extra cost). And have no way to monitor when the headlamp is reaching low voltage. I plan to buy a better headlight such as Sofirn SP40, Skilhunt H04.
In the meantime, I’d like to salvage this headlamp. Because my need is pretty modest, this headlamp works OK in terms of lighting in medium brightness. Especially after I added diffusion film (#7 + orange filter bought from Boaz user in this forum). I think 2x protected 18650 cells would help to compensate for the lack of low voltage protection of the headlamp. And it looks like the battery case has enough room to accommodate 18650 cells with longer length. Do you think it is reasonable to use this headlamp with protected cells?
Why do you think there is no protection? What is written on the side of the cell, as seem in the picture above?
[edit] On second thought they look like these ultrafire fakes—are you cells ultrafires? They don’t appear be Sanyo cells or to have the extra crimps at the top that a pcb cell would have.
+1
Those 18650 cells appear to be protected.
I have no idea. I don’t feel the flat wire (of the PCB?) linking the top & bottom as seen in photos of protected 18650 cells. Furthermore, the description on cheap Chinese products is not always accurate. Like exaggerated lumen units or mAh capacity. I just assume those batteries have no protection against running below low voltage .
Reading about PCB in the link given by member Barkuti above, it seems that the protection will work the way I hope. ie it has built-in Low voltage protection, which the headlight cannot provide. It just the description in the 18650canada.com store about tripping PCB which got me confused.
BTW, knowing the risk of killing a Li-ion cell if run below low voltage, I wonder who would design a flashlight without LVP and without a warning LED. If I knew those technical details I would never buy such a product.
It is something to keep in mind when gifting a flashlight to someone without a DMM who will not test the batteries periodically. But for myself, the other features of the light are more important than protection. Testing voltage and charging batteries is part of the hobby.
go back and look—i edited that post. check out the links. Better get some real cells that can be trusted.
I couldn’t say one way or another but from the written wording it does appear to be useless if tripped.
That’s not how a normal LVP battery circuit works. Never heard of one like this, unless they are talking about the factory CID or PTC.
They say it stops the battery from working and can not be reset. Even if a LVP circuit fails you can still unwrap the battery and take off the circuit board and use the battery unprotected. So it could still be used if they are talking about a circuit board.
If they are talking about the CID or PTC then its no different than any other factory battery that uses these features, which most do.
Its really not clear what protection it has. 
Unprotected cells (≈65 mm lenght). Protected cells are always a few millimeters longer, usually between 68 to 70.5 mm.
That headlamp is unlikely to over-discharge the cells. If in doubt, stop being adamant and test it. See what I said above in #7. Leave the lamp powered on with cells inside for 2 - 3 days, the emitter will be barely lit after that time. I am pretty sure it uses some sort of unregulated and/or linear driver, current drain drops as battery voltage drops and collapses over the emitter Vf. You'll need a multimeter to check cell voltages. You can check cell voltage from time to time if you will.
well, lets assume there is no protection in the batteries and no protection in the light, for sake of example
now imagine you are using the light and it starts to get very very dim. Noticeably very very dim… I mean DIM!
well, thats a warning that the battery is reaching exhaustion.
the prudent thing to do, if you are going to use LiIon, is to have a way to test the battery voltage. Especially when the light gets DIM!
avoid draining the battery below 3.6 volts… but when the light gets dim, the battery may already be at 2.7 volts. The only way to use unprotected LiIon safely, is to measure the voltage periodically, even before the light gets Dim…
agree!
As jon-slider says the light is going to become very dim when the battery voltage is low.
You can look at TA’s xp-l2 test data and look at the vf (blue) vs Output (orange).
This is the actual voltage to the led. A battery will have voltage sag under a current load.
This is only a example, leds have different vf’’s at the same current but they are typically close.
At a loaded battery voltage of 2.5v your going to be almost in the dark. Once the load is removed the battery voltage will bounce back.
You should be able to recognize the battery is getting low visually way before the battery is at 2.5v loaded.
.
This does depend on what mode your are in though. If your using the light in low mode and only drawing a few ma’s then your probably not going to notice much change in output until the battery is below 2.5v loaded. Best to check voltages but using in a higher mode will let you know once you have done it a few times.
Thanks jon-slider and you too 007. Now this explains everything (bold emphasis added). I am much less concerned now because I am confident I will be able to detect visually when the light get uncomfortably dim. I don’t have an instrument to measure voltage and even if I have, I prefer not to bring it with me during a hike.
I didn’t know that a LED will stop functioning around 2.5V. I thought it uses the Li-ion cell like a gas tank. It stops when the tank is empty which to me is equivalent to 0V and means dead cell. With this gas tank analogy, a cell around 2.7V to 2.5V is more than 50% full. So I thought the LED should continue to work perfectly, even though it is about to kill the battery.
So then problem solved. Usually I finish the hike before the light gets noticeably dim. When it did, I switched to a backup light. Nevertheless, I will follow your advice to buy a multimeter. For the sake of learning to get acquainted with caring Li-ion cells.
Better yet, get a flashlight with Anduril UI. Three clicks gives an approximation of battery voltage… close enough for practical purposes. Check it with a cheap DMM (Harbor Freight under five bucks) if you want a correction. Carry an extra battery and change it at your desired discharge voltage, maybe 3.4 or 3.5V or whatever you wish. Your battery will last longer by avoiding deep discharge cycles that cause increased anode degradation.
Those two batteries you received with the headlamp are unprotected. It’s the same wrap used on protected and unprotected, Sofirn used the same wrap on the first version without protection until someone on BLF mentioned it. Their battery now has a black wrapper.
I’d just plain stay away from anything that cheap. Usually a safety risk