Should I be scared my Acebeam K70 might explode?

rickypanecatyl

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So the quick story: I got a Acebeam K70 with XHP35 High Intensity several weeks ago. At the same time I also bought (4) new Olight 3200 mAh batteries (ORB- 186P32) to be used exclusively with the K70. (Anytime I get a new light requiring more than 1 lithium ion batteries I always buy a new set together, use it exclusively for that light, always charge them together and when possible, try to get a different color battery to go with the different lights!)

The light worked great till last week and I used it often. When camping several times I left the light on all night in the lowest (.5 lumens?) mode which I do to help me find the light in the dark.




So last week we were going for a night ride with the family in the jungle. I had topped up the batteries before leaving and so they were fully charged. Putting it back together I tested the light in high and low and it seemed fine and I turned it off. We used the light a couple times on low in the landcruiser to look for stuff inside the vehicle on the trip out. About 30 minutes later I hear something out the window, turn the light on high and click the tail switch but nothing happened. I played with it for a bit, moving the selector ring to different modes, turning it off and on but it never turned on. We all noticed a really smell but at first I thought it was the vehicle. Stopped, popped the hood, grabbed the light (forgetting it didn't work!) and it was so hot it hurt to touch it and would have burned my hand if I held onto it.
I got my wife and kids away, took the battery tailcap off and let the battery holder slide out onto the ground. It was extremely hot, smelled horrible and the front of the batteries looked like they were melted.

So any thoughts? Could it be the batteries? The light itself? I was wondering if perhaps something shorted on the battery carrier? Should I try it again?

Taking the battery carrier out:







 
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mhanlen

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The Acebeam K70 has a dual spring setup in the battery tube an outerspring for the negative and an inner spring for the positive. I own many lights and I never have seen this... but to me the first thing I'd think is lithium ion batteries have shorted against one another. Make sure those springs are properly aligned and not touching. I know that the springs got goofed up once, and I had problems closing it. This seemed to happen if I removed the tailcap... so I realigned them and started removing the battery tube from the head, and it never happened again.
 

rickypanecatyl

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Thank you sir! You are a genius! (Or I'm an idiot!) :)

Here's what I found when I took the tailcap off...



The inner coil is mushed into the outer coil definitely making contact. So is it safe to assume that is what the problem was? As I try to image how it screwed back together it looks like the inner positive spring would have mushed more into the outer negative ring when tightened and never made contact with the inner part of the battery carrier ring.
 

easilyled

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That is concerning. I also have a K70.

Looks like they should have at least designed an insulator sleeve or something equivalent between the inner and outer springs.

Thanks for the warning and glad you're ok.
 

Modernflame

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Here's what I found when I took the tailcap off...



The inner coil is mushed into the outer coil definitely making contact.

And just when I was ready to blame a faulty cell...

Thank heavens everyone is alright and the incident occurred outside, where everyone is far less likely to inhale toxic fumes from the battery.
 

mhanlen

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I'm pretty sure that's what the problem was. I can't say if it fried your light, I'd put in a second set of batteries and monitor it very closely. I would definitely not use the tailcap as the entry of the battery carrier any more. I never had cells heat up or short, I just had a hard time screwing it down- which is how I noticed. Removing the cells via the head helped, and it never has had that problem since (well over a year of ownership).
 

Rockjunkie15

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I had thought there was some kind of warning about not removing the cells via the tail cap, this is obviously the reason. I've probably changed my K70 batteries nearly 50 times by removing the head and have not had a single issue. Bend that spring back and get some fresh cells and you should be set. Glad to see that pretty flashlight didn't pop, kinda scary to think about.
 

proceed5

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I have owned and been using regularly my k70 since April 2016.
My K70's tail cap is locked in place (factory default) and for any battery changes I will need to unscrew the head portion to remove the carrier, this have been done countless times.
I have never used any protected Li-Ion battery set with my k70, I always use only unprotected flat top Li-Ion or IMR batteries and It has always been fine and very reliable.
Thank goodness you are ok.
 

rickypanecatyl

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The Acebeam K70 has a dual spring setup in the battery tube an outerspring for the negative and an inner spring for the positive. I own many lights and I never have seen this... but to me the first thing I'd think is lithium ion batteries have shorted against one another. Make sure those springs are properly aligned and not touching. I know that the springs got goofed up once, and I had problems closing it. This seemed to happen if I removed the tailcap... so I realigned them and started removing the battery tube from the head, and it never happened again.

So after I get the springs nice and straight that's exactly what I'll do. I found the head was quite a bit harder to unscrew than the tailcap so my plan (I'm throwing out here for all ye all's thoughts!) is to lube the threads between the battery tube and the head and put lock tite on the tailcap threads in case I forget again!
 

Connor

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@rickypanecatyl
Since it hasn't been mentioned yet: do not try to charge any of those 4 batteries again, once they've been shorted like this they're defective and dangerous and can go :poof:.
 

bwalker

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So is this issue isolated to the K70 or are other Acebeam's sharing the same design?
 

Lou Minescence

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Looks like Acebeam should make a better set up for the batteries. A lot of this performance and technology is pushing the limits of safety. Glad all are ok. There are some lights I pass on because I can see something going wrong if I owned it. Maybe the K70 is a light for me to pass on. Fun but potentially dangerous. Like anything that is fun. Potentially dangerous.
 

Lou Minescence

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Looks like Acebeam should make a better set up for the batteries. A lot of this performance and technology is pushing the limits of safety. Glad all are ok. There are some lights I pass on because I can see something going wrong if I owned it. Maybe the K70 is a light for me to pass on. Fun but potentially dangerous. Like anything that is fun. Potentially dangerous.

Did the batteries trip their protection circuits ?
May be too late to tell without a volt meter.
Just curious
 

Crazyeddiethefirst

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The Olight cells I have are by far the longest of any cells I own-fortunately for me, there was such a difficult time trying to tighten the tail cap I stopped. One spring was bent and if I had gone just a little further, I believe it would have shorted. Perhaps replace with batteries that are shorter but still protected?
 

mhanlen

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I only have the X45 for comparison- and it's a different design, with no tailcap and no spring in the bottom of the battery tube.
 

SoCalTiger

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Wow that's a bit scary. Good thing that you acted fast and got your family away and everyone seems to be alright. That is an unsafe spring design for sure.

Looks like those batteries are protected. It's also concerning that it doesn't appear that the protection kicked in to kill the current when the short happened.
 

martinaee

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Oh man... Maybe I'm wrong, but doesn't that seem like kind of an inherently dangerous design? The spring can literally bend into the other spring shorting it out. What is the purpose of that dual spring design? They aren't using the tube or a part of the tube as the circuit?
 

aginthelaw

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There's a cushion you can slip over a pencil so you get a better grip when you're writing. I'm going to give that a shot, over the center spring when I get a chance
 
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