Battery Protection Circuit Gone Bad?

Marquis07

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Hey,
I have several 18650s that go into a "dormant" state and I have to wake them up if I want to use them.
The batteries are thrunite, but I think they're rewrapped samsung 30Qs. The lights I run the batteries in are thrunite as well, and they have built-in charging ports. The batteries came with the lights.

The issue arises when I swap cells. My backup cell will be fully charged, but when I stick it in the light, nothing happens. To fix this, I only have to plug in the light for a second to charge it, and the cell works like normal. I have at least 2 cells with this issue, and it happens in several of my lights, so I know it's not the light.

What might cause this, should I see if warranty would cover it?

Thanks,
Mark
 

aznsx

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All I know is that with some of my protected cells, if they have 'tripped', they go to 0 VDC. The way I reset that condition in my experience has been to stick them in my Xtar VP2s, begin charging, and they are instantly 'reset' and have (at least somewhat) normal output. Some have said they simply connect a normal cell in parallel briefly, and that 'resets' them.

I don't know if yours are experiencing over-discharge, over-current, or what - not a cell expert at all. Since they restore / reset to near normal full voltage, I assume it isn't undervoltage (overdischarge), but can't say what's shutting them down in the first place. i'd be concerned until I determined the answer to that question specifically. I'll leave it to others who know a bit about cells to speculate regarding that. I suspect 'overcurrent'(?).

If this happens in storage (not in use), I'd likely discontinue using them until I figured it out, but I tend to err on the side of caution with these things
 
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Marquis07

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All I know is that with some of my protected cells, if they have 'tripped', they go to 0 VDC. The way I reset that condition in my experience has been to stick them in my Xtar VP2s, begin charging, and they are instantly 'reset' and have (at least somewhat) normal output. Some have said they simply connect a normal cell in parallel briefly, and that 'resets' them.
That sums up exactly what is happening to my cells. I don't know what trips them though. The cells don't consistantly trip. Sometimes they work like normal, and sometimes not. I need to be able to rely on them, and this makes it quite frusterating.

Normally, I notice the cells are tripped when I go to stick a charged one in a light. It's almost like the cell trips when there is no parasitic drain. The cell can work fine in one light, but as soon as I swap it to the next light, it is instantly tripped.

The one cell could definitly be overcurrent, I've overdriven it in the past. The other cell(s) are original with the lights, so they should not be overdriven.
 

dragosios

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It's very difficult to pinpoint if the cell itself self-discharges or there is something in the protection causing the self-discharge.
The only way I think it could be done is to separate the protection circuit from the cell, which is ... destructive.
 

aznsx

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It's very difficult to pinpoint if the cell itself self-discharges or there is something in the protection causing the self-discharge.
The only way I think it could be done is to separate the protection circuit from the cell, which is ... destructive.
& @Marquis07

...only issue I have with that line of thought is that the affected cell isn't actually discharged / over-discharged at all. It reads 4.19 no-load after reset. That's not the case when I overdischarge a cell (by any means), even to the point of protection shutdown. They will continue to read very low, open-circuit after being reset, until recharged (or in my case, reset by the charger itself with some cells) That's why I'm thinking along other lines (although not conclusively).

At the very fundamental level & w/available info, my gut keeps reminding me of the basics; that this occurs with multiple cells, but with the same light. Therefore, I can't rule out an intermittent defect in the light itself as root cause, possibly triggered by the actions associated with when the OP "swaps cells". Many might recommend checking the cell(s) in another light, or checking the same light w/ a new / known-good cell. At this point, all the involved cells could be 'junk'...or the light could be defective (even if an intermittent failure as above). The root cause needs to be 'ballparked', or isolated to one or the other device if possible, then analyzed in further depth based on that determination.

If they were or are of marginal rating on 'output current' for the specific flashlight model, and they have aged / degraded in use, they may all just now have insufficient current-sourcing capability for the light involved, particularly if it starts on 'max' output and ramps down (which might expose the problem even more. That can absolutely happen, and I'm fairly certain it has happened to me before.

Just 'thinking out loud' here and tossing out things to be considered...

Nothing conclusive, but a possible way forward towards isolating root cause.
 

aznsx

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^^^^^^^^^

An afterthought here. My most memorable experience along these lines involved cells which were (inappropriately) sold by a manufacturer for a given light, but could not actually reliably deliver the current the light required. If they did initially, they didn't after just minimal use / charge cycles. The light would unpredictably shutdown, primarily after startup at high output before ramping the output down, or upon switching to high output from a lower one. The cells would 'trip' and goto 0 VDV open-circuit. The shutdown was not self-resetting, but had to to 'reset' by the means I mentioned in my earlier post: in my case, merely inserting them into my Xtar did the trick.

The cells measured ~4.2V initially / prior to installation, and still measured ~4.2VDC at the conclusion of the entire above process. There was no 'over-discharge' in the true meaning at all. They had shut down due to their inability to deliver the current required by the light. Ran me crazy for a bit.

Does this sound familiar @Marquis07 ?

Anyone remember the original Olight S1?:)
 

Marquis07

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Here's a bit more info.

I have 3 TH30 Headlamps and a TC15 that all came with IMR18650s.

I also have a thrunite PB with a regular 18650 in it.

The IMR cells are rated at 15 Amps and the reg cell at 10 Amps.

I've been using the reg 18650 in my lights because I needed a backup and it worked. The lights only use that many amps on high/turbo, so I figures it would be fine if I didn't use the lights on high with that perticular cell.

The reg 18650 is the cell that has issues.

One of my IMR cells sometimes has issues, but it is not consistant.

The reg cell works fine in my headlamps, and I can swap it between them just fine. There are no issues.

The reg cell does not work in the TC15 unless I reset it.

Example 1. I remove the reg cell from a headlamp and put it in my TC15. The TC15 will not turn on even in firefly mode. The cell is tripped. To fix this, I plug in the cable to charge the light and the cell is reset.

Example 2. I remove the reg cell from a headlamp and put it in my TC15. I then remove it from the TC15 and put it back in the headlamp. The cell has been tripped and will not turn on. To fix this, I plug in the cable to charge the headlight and the cell is reset.

Example 3. The reg cell has been put in the TC15 and has been reset. The TC15 is working. I mechanically lock out the TC15 and then unlock it. The cell has once again tripped. To fix this, I plug in the cable to charge the light and the cell is reset.

The cells measured ~4.2V initially / prior to installation, and still measured ~4.2VDC at the conclusion of the entire above process. There was no 'over-discharge' in the true meaning at all. They had shut down due to their inability to deliver the current required by the light. Ran me crazy for a bit.
That sounds very familiar, I assume you just replaced the bad ccells? I think I'll get a bay charger soon and then a bunch more cells. How do you like your Xtar VP2?
 

aznsx

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Here's a bit more info.

I have 3 TH30 Headlamps and a TC15 that all came with IMR18650s.

I also have a thrunite PB with a regular 18650 in it.

The IMR cells are rated at 15 Amps and the reg cell at 10 Amps.

I've been using the reg 18650 in my lights because I needed a backup and it worked. The lights only use that many amps on high/turbo, so I figures it would be fine if I didn't use the lights on high with that perticular cell.

The reg 18650 is the cell that has issues.

One of my IMR cells sometimes has issues, but it is not consistant.

The reg cell works fine in my headlamps, and I can swap it between them just fine. There are no issues.

The reg cell does not work in the TC15 unless I reset it.

Example 1. I remove the reg cell from a headlamp and put it in my TC15. The TC15 will not turn on even in firefly mode. The cell is tripped. To fix this, I plug in the cable to charge the light and the cell is reset.

Example 2. I remove the reg cell from a headlamp and put it in my TC15. I then remove it from the TC15 and put it back in the headlamp. The cell has been tripped and will not turn on. To fix this, I plug in the cable to charge the headlight and the cell is reset.

Example 3. The reg cell has been put in the TC15 and has been reset. The TC15 is working. I mechanically lock out the TC15 and then unlock it. The cell has once again tripped. To fix this, I plug in the cable to charge the light and the cell is reset.


That sounds very familiar, I assume you just replaced the bad ccells? I think I'll get a bay charger soon and then a bunch more cells. How do you like your Xtar VP2?

Thanx. Let me assimilate / correlate this info further, but just quickly for the moment:

  • Do you have any cell that can be used in the TC15 with NO issues? If not, you're not finished yet. Cells tripping protection circuits is a red flag, and needs to be eliminated (not just worked-around by resetting them) before you're finished.

  • Do you feel everything you've done / tried has eliminated the possibility of a (possibly intermittent) defect / failure in the TC15? If not, I'd consider that a required objective. So far, I'm not sure you've used / tried anything in it that actually works properly (?), and that should be (EDIT: near) the ending to this story. EDIT: You could easily have multiple crummy / marginal / worn out cells producing the same symptom(s), or just wrong for the application as in my case, or a bad light. It must be determined which applies (cell(s) or light before going further to root cause. That step cannot be skipped.

In the case of that S1, neither the light nor the cells were defective. The supplier was defective in supplying cells for a light which could not meet the current requirements of the light, and for that plus several other reasons, is a supplier I no longer use. Nothing was 'defective', just seriously mis-matched. Yes, I bought good cells for it with sufficient output current rating for the light, and that's all that was required. They set their customers up to fail, and that drove me and many others crazy until we figured out what they'd done. There are old threads on this site documenting the issues.

I have 3 of those VP2s, which tells you something. Two of those have seen good use for >5 years. They're essentially all I use for routine Li-ion charging. They have positively selectable charging current (3 settings), have appropriately low charge current option for my smaller cells like 16340 & 14500 (250 mA) [which it always defaults to, so I can't screw up], and can do 3 different CV charging voltage settings (also persistent and selected via a proper switch); including one for 3.2V LFP cells, which I also use and need to charge. They don't cover larger than 18650, and don't charge at anything >2 amps. I don't know if that's a limitation for you, but it's not for me. I know of nothing in Xtar's current lineup that meets all those criteria, which is why I recently bought a 3rd one (N+1 redudancy in my case), and because they're discontinued. They're still available as I type though - here's where I bought that 3rd backup / spare fairly recently, if you want to consider one. I'm not sure if there's another current, reliable source:


I consider all the Li-ion cylindrical cell chargers on the current market (EDIT: that I'm aware of) to be 'junk', by my professional standards, but relatively speaking, I consider the VP2 to be fairly good junk among what's available:) If I can't get anything I really think is good, I'll go with the best I can get. I have no option.

Consider those 2 questions above, and I'll review what you posted here later in closer detail. Those 2 questions I posed are, however, the ones I consider need to be answered (if you've not already). I'll review this latest info as well, but those are the 2 big questions at this point.
 
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orbital

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In the future, don't buy cells w/ crappy little pcb on them.

problems solved
 

aznsx

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In the future, don't buy cells w/ crappy little pcb on them.

problems solved
You might want to consider putting your bias against protected cells on hold: save it.

AFAIK, the required fundamental, initial isolation of root cause of the problem to either the cells or the light has not yet been made. That is as yet in progress. Please correct me if that's not the case.

AFAIK at this time, the single light (TC15) is experiencing problems with different cells. That would tend to, if anything, point to the light (TC15), not the multiple cells. Please correct me if that's not the case.

I would not personally assume at this point, but if the above is true, that info would tend to place the blame with the light rather than the cells.

Yet another thing you might not be considering is that this TC15 may have had a hard life of late, and if so, that would further increase the likelihood that the light is at fault. I have yet to confirm that this is the same light under current discussion, or if so that the referenced problem followed this work:


Let me know if you're seeing info in the OP's posts that I'm missing. In fault isolation, hasty conclusions are unacceptable, and not what the OP needs.
 

Marquis07

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@aznsx

I have 3 of those VP2s, which tells you something. Two of those have seen good use for >5 years. They're essentially all I use for routine Li-ion charging. They have positively selectable charging current (3 settings), have appropriately low charge current option for my smaller cells like 16340 & 14500 (250 mA) [which it always defaults to, so I can't screw up], and can do 3 different CV charging voltage settings (also persistent and selected via a proper switch); including one for 3.2V LFP cells, which I also use and need to charge. They don't cover larger than 18650, and don't charge at anything >2 amps. I don't know if that's a limitation for you, but it's not for me. I know of nothing in Xtar's current lineup that meets all those criteria, which is why I recently bought a 3rd one (N+1 redudancy in my case), and because they're discontinued. They're still available as I type though - here's where I bought that 3rd backup / spare fairly recently, if you want to consider one. I'm not sure if there's another current, reliable source:
That's good news, I think I'll get one before they're gone! I'm guessing you just use a spacer for 14500s right? The one in the link also says it covers 21700s.

Do you have any cell that can be used in the TC15 with NO issues? If not, you're not finished yet. Cells tripping protection circuits is a red flag, and needs to be eliminated (not just worked-around by resetting them) before you're finished.

Yep, all my other cells (protected and unprotected) work in it just fine. It's just the one trouble cell.


Do you feel everything you've done / tried has eliminated the possibility of a (possibly intermittent) defect / failure in the TC15? If not, I'd consider that a required objective. So far, I'm not sure you've used / tried anything in it that actually works properly (?), and that should be (EDIT: near) the ending to this story. EDIT: You could easily have multiple crummy / marginal / worn out cells producing the same symptom(s), or just wrong for the application as in my case, or a bad light. It must be determined which applies (cell(s) or light before going further to root cause. That step cannot be skipped.

Yet another thing you might not be considering is that this TC15 may have had a hard life of late, and if so, that would further increase the likelihood that the light is at fault. I have yet to confirm that this is the same light under current discussion, or if so that the referenced problem followed this work:

It's had a hard life from the start. I've dropped it several times from various hights and I've carried it every day for the past 1 1/2 years.

Yes, this is the same light that I "refurbished". I honestly don't know if the issue started before or after that, but it happend around the same time. I did try to remove the pcb when cleaning off the ano, and while I was gentle, I may have damaged it.

At this point I'm going to assume that the fault is with the light, and not the cell... Although, it's still only one cell with the issue, and that puzzles me.

I'm waiting for @ExceedDesigns to finish his prototype:poke: and then I may upgrade from the TC15.

Thanks for your help figuring this out. I appreciate it.



-Mark
 

aznsx

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That's good news, I think I'll get one before they're gone! I'm guessing you just use a spacer for 14500s right? The one in the link also says it covers 21700s.
No, one good thing about this (unlike my Opus), is that it works very well with both 14500 and 16340. I do have to use a spacer with 16340s (which I use a lot of) in the Opus because the spring pressure is insufficient for a reliable connection without it. They're a pain to use, which is one reason why I use the VP2s almost exclusively for simply charging, and the Opus mainly for discharge / capacity / internal resistance testing.

They should have listed 16340 & 14500 as well - an oversight on their part. I use mine more for those sizes than anything else.

Thanks to you as well for informing me about my own VP2s! I had no idea they would accommodate those larger sizes (as I currently have none)! Now I know that if I do perhaps buy something using 21700, I'll already have chargers I can use with them. That's cool! Thanx again! Good trade of information!
 
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