A bizzare incident - explosion and fire - Opus Battery Charger

I have debated posting about this for several reasons. (1) I know that all regulars here are well versed in safety and I assure you I am too. (at least that’s what a sheepskin says) (2) I don’t want to alarm anyone- I consider this an isolated and bizarre incident and I do not know what caused it. (3) somehow I escaped injury… how I also don’t understand.

A week ago a battery and battery charger exploded. I was setting within 3 feet of it and it went off like a grenade. The batteries flew 15 to 20 feet across the room along with hot fragments. One battery was so hot that it melted the carpet where it landed and there was little left of the second. My dog Mr Pipes suffered a small burn but is fine though the poor guy was totally freaked out. The house was full of smoke and the fire department was called. I got the dogs and my wife out and looked for anything that I could extinguish. Nothing. They arrived and inspected and then used fans to clear the smoke and fumes. If this ever happens to you don’t breathe the fumes. The paste that is inside these batteries is nasty and also hard to clean.



I am now building a metal box with computer fans to ventilate my chargers and will now only charge inside it. If something explodes again it will contain it. How I wasn’t hit by anything is a mystery to me. I’m not telling anyone what to do but this scared the shit out of me. I’m not too thrilled about replacing carpeting or having to paint either.


I’m just glad that you and Mr Pipes are OK.
As you say it is quite bizarre, but of course it is always a possibility with our batteries.
What battery was it, and how old was it?


Thanks, Pipes and I are fine and amazingly I have 20 or 30 little burn spots in the carpet yet just one tiny burn on him. Both dogs were at my feet as usual. Best buds. :grinning:

There were 2 18650’s in the charger. Both were “married” Samsung 25R,s . I’m not sure of the age but they had been used awhile and I didn’t notice anything wrong with them. The charger was an Opus less than a year old. Opus is highly regarded yet I suspect it. Notice how the front is blown off. But I really don’t know what happened.


Damn bro, I’m glad you’re both all right. I’ve been playing with the idea of putting my charger in a cool-box that I have, just to be on the safe side.
I get paranoid ideas sometimes :sweat_smile:
Till now I’ve been too lazy to clear out the flavours I’ve been keeping in it, but now you’ve given me an incentive. I also own an Opus for my 21700’s :scream_cat:


I have never used an Opus, so have no first hand knowledge of them.
I only have eFest Luc V4 and Nitecore I2 which thus far have been fine.
The Samsung 25R’s are well regarded batteries so they should have been fine, I’m running about 30 of them myself, some married and some individuals.
It will be interesting as to whether anyone else may be able to shed any light on this.


Wow, glad you are ok, was there a battery in bay 3 by chance? It looks like thats where all the damage is concentrated, only thing I can think of is a short in the charger, I have a Nitecore D4 EU edition, this has certainly made me think twice about leaving my charger on when im out, thanks for sharing


This is pure speculation and I had a high opinion of the Opus. Both batteries were red hot but only one exploded and the other just split. That leads me to consider the possibility or probability that they were overcharged until they blew. Parts of the circuit board was in melt down condition and as the photo shows the front blew out. They were in the charger for a couple of hours. If one was internally shorted it seems to me that any problem would have been instant when I put it in the charger. However, an internal short can happen at any time.

Edit: if it developed an internal short the amperage would go sky high and should have blown something in the overcurrent protection which it should have. Its so fried I can’t tell.

@Jose. I don’t want to alarm you or say that the Opus is not a good charger. But the box is a great idea. Better safe than sorry.


Wow this make me re access my battery charging methods - I know if it was posted elsewhere the know all brigade would come out with a barrage of BS.

I am glad Mr Pipes is ok and the damage was contained to carpet and paint.

I doubt you will ever find the actual cause but is sure as shit a wake up for me.

Thank you for posting and making us all think about it.


On a side note the Nitecore D4 supposedly stops trying to charge the battery once it is full, does the Opus have that?? I know some will continue trickle charging


Yes. It worked fine and spec wise it seems like it is a notch or two above most of the other chargers. Even has a cooling fan. I agree, it points to a short or bad malfunction in the charger to me. Be interesting to hear what @SmilingOgre and @Sprkslfly have to say.


I’m amazed (and thankful) that you guys escaped without serious injury. I also want to add my thanks for sharing the situation.

As you mentioned, I too have long thought highly of both components (Opus and Samsung) involved in the incident. Talk about a serious reminder that nothing is infallible (or beyond reproach) when it comes to dealing with Lithium-Ion technology… :flushed:

/my speculation from observations

Agreed, and good eye.

I’m strongly inclined to believe that the battery that exploded (and there was ‘nothing left of’) had to have been in bay 3. As judging by the pattern left by shrapnel, and knowing that the charging position of the battery is positive to the top, it is logical that it vented in an almost 360° pattern which radiated from the top of the battery (away from the side of the battery). The bottom being a single, solid ‘plate’ did similarly, but with marginally less force, thanks to its construction (which I can only assume directed the majority of the force to the top).

It’s interesting to note though, that there doesn’t seem to be much damage at all to the underside of where the battery is assumed to have been in bay 3.

The above is what leads me to believe that the battery was at fault, and shorted/exploded faster than what the charger could react to.

That last sentence though is what really throws me though. I strongly agree with @mrpipes that one would think (hope) that the monitoring circuitry would catch whatever ‘condition(s)’ were encountered BEFORE things escalate to a full on venting condition.

It also reminds me that I am curious about a couple of things.

What version of the Opus did you own? 1.x, 2.0, 2.1?

Did you ever test the batteries in the charger (regularly or otherwise)? Meaning, to not just charge them, but to get the overall condition (such as resistance, max capacity, etc)?

I’ve got some 25r5’s here that are approaching 3 years old (if not already that old), and while the max capacity has dropped off to an average of around 1800mah… I’m overdue to test them again for the resistance measurements.
Fortunately, I have replaced the majority of them (in daily use) with newer 30Q’s. (But OTOH, that only means increased reserve potential at hand to vent [God forbid]).

My line of thinking is…
I’m wondering if the internal resistance of the battery falls too far outside of spec (for the charger to ‘safely calculate’ or measure), then a window of ‘fail condition’ could open up…and you’d get what we see here?

/my speculation from observations OFF

Knowing full well that there’s really no way to know exactly what happened, in what order, I am still inclined to believe that the more info we can piece together, might help for future knowledge. (Better to have extra details, and not be useful [now], than to not have them, and learn they could have been important [down the road])

/random thoughts I haven’t had time to process yet

  • how can a battery seemingly explode in place, leaving no remnants embedded in the charger (adjacent to the side of the battery, underneath the battery)?
  • IF the battery started to vent (blowing both ends off of the charger where the battery was) from the ends first, was there then a further degradation of conditions which expelled the battery before it “exploded into nothingness”? (Which could explain there not being any shrapnel embedded in the ‘side wall’ of the chassis underneath the battery. But then proposes another question of “in order to eject the battery, one would think there would have to have been force exerted from the bottom side of the battery” [between the battery and charger] which again implies there should be shrapnel embedded in the area of bay 3)

So many questions… Such limited information out there (not pointing at you Dan, just touching on Li-ion venting conditions testing that’s in the public domain).

/parting thought
Times like this make me wish Mooch was able to run a series of venting tests in a controlled environment using a high speed camera (with varying chargers and batteries).

Sad day. But invaluable reminder.
Thank you again.


Considering that both batteries were red hot, one exploding and the other splitting, makes me think that it is the charger. To me both batteries failing at the same time seems highly unlikely.
However maybe the battery in bay 3 overheated the battery in bay 2 causing a chain reaction.
Would it be worth reaching out to Opus for their opinion?


Yes, it was in bay 3. The pair were in 3 and 4 with 1A charge rate. I never set it higher. As to venting this thing went off like a shotgun or grenade. It left my ears ringing.

I don’t recall the model number but it was the latest. I asked here on forum for advice and I think that was when @Jim22 and @Jose bought theirs also to charge 21xxx batteries.

I have a shit ton of 25 R’s and did test a lot of them after I bought the charger… meaning no I most likely didn’t test all of them. After that I have been way too lax about it and was relying on noticing a drop in charge rate and capacity. You have probably hit the nail[s] on the head.

One reason I was hesitant about posting was that the protective circuitry is (as I understand it) part of the regulatory function rather than a separate device like a fuse. You and Ogre know far more about this particular type of circuitry than I do. My thoughts were that it would be nearly impossible to occur yet as I mentioned the batteries were red hot indicating overcharging to me. Shrapnel went flying everywhere. While waiting for the firetrucks I searched the tops of our kitchen cabinets trying to find the battery that had disintegrated.

Finally, a coherent and plausible explanation. :+1:

Thanks !!!


I wondered that myself. I wish I had saved the shrapnel and split battery. Firemen were searching for and removing them. They even moved furniture to make sure something wasn’t smoldering in or behind it.

Probably should have. The remnants went to the landfill. The smell was overwhelming.:+1:


Thanks for the heads up. Information is always a good thing. I haven’t had any irregularities with mine but I may replace it anyways. $30 isn’t worth risking disaster. A general search of " opus battery charger problems" turned up a few results like this:


Good to know.
While it may be a false sense of “added safety”, the whole reason I’m not nearly as comfortable charging at 1A, is that the time or two that I did test that level of charging, I noticed a distinct rise in the temperature of the batteries while being charged at that rate.

/EDIT: I neglected to mention that I only charge at the 500ma setting. /edit

I figured I’d rather have to wait a little longer (or buy additionally sets for rotation) than to shorten the lifespan (which I assume has to be a side effect of the increased temp cycling, which I would also believe to have a cumulative effect on the internal resistance).

Again, I’m not anywhere near as versed as Mooch or others… But this is from my understanding, and my approach as a result of my understanding.

I understand, and I think that’s probably what most people do.

What I’d really like to see is Mooch (or someone with similar knowledge) weigh in, and see if anyone has any kind of concrete data on the upper limit of the safe margin of internal resistance to operate in.
(EG: Properly discard your “brand x, model y” battery if the measured internal resistance meets/rises above ‘xx’ reading. Of course, this would be expected to vary from brand and model of battery… So a load of further testing for the most commonly used variables alone would be in order.)

At least, that could add one more layer of safety between the user and the Li-Ion technology.

As do I, but, it’s probably for the best that you didn’t. I know while my curiosity is at a peak, the risk of handling/exposure to certain chemicals (as a general rule) can have long term consequences. And knowing enough to realize that I don’t have the necessary information about the ‘raw goo’ inside tells me I have no business handling the exposed insides of one. So I damned sure wouldn’t ask/expect someone else (with the same level or less) to.

@Steampugs @mjag @woftam or whomever…
Could I ask one of you gents to request Mooch’s presence (or at least ‘eyes on’) to this thread?
I’m sure he doesn’t know me from Adam…
Even if he replied elsewhere, I’d simply be grateful for his thoughts.

And like @mrpipes, I’m also very interested to hear @SmilingOgre’s thoughts. :slight_smile:


Thank you for sharing this video (and your thoughts of course).

I have been hesitant to add (before now in this conversation) that just within the last 24 hours, my BT-C3100 v2.1
<EDIT for accuracy: just double checked mine, and it’s actually a v2.2>
has just started to exhibit some of the symptoms shown in the video (specifically the unit on the left) that you just shared. It’s at least two years old (and probably older, but I’d have to check)

I took immediate notice of it, and DID NOT dismiss it… But haven’t had a chance to look into it further yet.

I instantly thought, “ok, time to start thinking about replacing it.” But this just took that thought to Priority 1.

As you say, the risk FAR outweighs the cost.

I will also note, that the conditions are persistent, and the monitoring appears compromised until the unit is unplugged and self-resets.
HOWEVER, just like with the digital thermostat I just replaced for my mom’s AC unit (days ago), once a device has been exposed to a power surge (not saying his nor mine has with any guarantee), it’s never trustworthy again IME.
And I’d be far more inclined to think that that’s what might have corrupted the charger (if the charger were to blame). Again, just supposition and educated guessing going on here…


First off @mrpipes I am glad to hear everyone is ok, second off that is some seriously scary stuff.

Like many here I am going to think of ways to improve the safety if my charging. I charge in a room with tile floors and the chargers sit in granite but now I know that is not enough if something like this happens. I am going to look into that box with computer fan venting you mentioned. I know they make boxes for safely charging Lipo’s in, never researched were to get them though.

Thank you for bringing this to our attention and sorry it happened to you but thank God everyone is Ok.

@Sprkslfly I have only spoken to Mooch once but will reach out to a friend who may know him better and see if he can weigh in.

Edit: Contacting VapeyMcGyver from reddit as well, he might be able to help. If not then I can just post this over on reddit with @mrpipes permission, Mooch tends to hang out there.


Here is something for the Lipo user’s, I don’t think you can put your charger in it though, anything similar for a charger?

They have a bag at Amazon too for Lipo, something like $14 but my mobile just keeps opening the amazon app so can’t post a link.


Wow! @mrpipes, I am so thankful you and your’s were not hurt. You have a lot of great input already here and I doubt I have anything to add. @Mjag, Not sure about the Bat-Safe. Does it provide cooling? The bags and such will contain a thermal runaway reaction but often also promote it allowing internal temperatures to rise more than they would in open air. Having said that, the amount of effect is dubious as the chemical reaction initiating thermal runaway starts from within. As to the causation, I have no idea. Faulty battery, sure. Faulty charger is possible too. I don’t have enough information on the charger to assess if a failure mode could be placing an shunt across the terminals of the battery or under what circumstances a battery could go into thermal runaway as a result of overcharging. As per others, I would defer the evaluation to Mooch. I have had little formal education on batteries themselves.

Again, just glad you weren’t hurt.