9AA - 3D heating out of flashlight

I just got a FiveMega 9AA carrier for my Mag85 build. I'm using Eneloop batteries. When I first assembled the battery carrier with the batteries (about 4 days ago), everything seemed to go fine. I took the battery carrier out tonight to connect the charger wires to the supplied male plug. The battery carrier was sitting for maybe 2-3 minutes, on its own, separate from everything else.

When I went back to grab it, it was extremely hot. I quickly took it apart and let it cool. Now when I go to reassemble it, I stack all the batteries in the carrier - no problem. But then when I go to screw the positive end of the carrier in, it sparks between the brass and aluminum and starts getting hot again in a hurry.

What did I mess up or what is messed up that's allowing current to run through the carrier when it's sitting on the table?

I've checked and double checked to make sure the batteries are facing the right direction. It seems like something's making contact that shouldn't be????

oo:

Ok... after a little investigation, it looks like the nut on the negative end of the carrier (between the acrylic and aluminum) came loose, made contact with the negative end of the carrier, and was completing the circuit.

Current ran from the negative end of the carrier, through that bolt, up the center post, to the positive end of the carrier, and then back through all 9 batteries.

Is that feasible? Is that nut supposed to be affixed to the acrylic so it can't contact the aluminum negative end?

So how do I fix it if that's indeed the case?

I suggest you contact FiveMega directly

The same thing happened to my Fivemega 12 cell holder. Three Eneloop cells vented before I could get it out of the light and take the holder apart.
I left the nut off and just left the center pole threaded into the acrylic end piece.
A very dangerous design if you ask me. We are both lucky it happened right in front of us. I was going to put my light away when I noticed the body getting very warm.
I'm sure a very costly light would have been ruined.

I have 6AA>2D holder; I cannot find the nut you're talking about. Either it's a different design or I misunderstood your description.

larryk said:

The same thing happened to my Fivemega 12 cell holder. Three Eneloop cells vented before I could get it out of the light and take the holder apart.
I left the nut off and just left the center pole threaded into the acrylic end piece.
A very dangerous design if you ask me. We are both lucky it happened right in front of us. I was going to put my light away when I noticed the body getting very warm.
I'm sure a very costly light would have been ruined.

Click to expand...

I ended up doing the same thing - taking the nut off entirely and just using the acrylic as the nut. It holds alright for now. I was trying to think of ways to fix the poor design. Maybe I'll countersink the nut into the bottom of the acrylic so it will be surrounded on 3 sides by the non-conductive acrylic. But then again, relying on air alone to break the circuit is, as you said, a very dangerous design. :thumbsdow

Maybe the smaller holders do not have the nut - my FIL thinks his threads into the acrylic only. Either he's mistaken, or the nut is new.

kurni said:

I have 6AA>2D holder; I cannot find the nut you're talking about. Either it's a different design or I misunderstood your description.

Click to expand...

I'm fairly sure it's a different design. The nut is in here, under the acrylic, and designed to fit into a "column" within the aluminum base.



I PMd FiveMega - hopefully he'll take this seriously. At least 2 of us have had the problem with the "new" design.

Yours seems to be different than mine; I assume your pic shows the negative end; it is definitely bigger than mine.

Positive end


Negative end


Thanks,
Kurni

kurni said:

Yours seems to be different than mine; I assume your pic shows the negative end; it is definitely bigger than mine.

Click to expand...

Yes. My negative end does not step down as small as yours. As you can see in my pic, there is a step-down, but it's minor.

My positive end is the same as yours.

I have the one Kurni has, half of my elite 1700s melted in it before I got them out. Odd thing is, it was never a problem that occurred charging it with the battery stack stuffed in the mag body...

What charger are you using?
I'm using this: http://www.batteryjunction.com/unsmch.html
I haven't tried eneloops, are they compatible?

Phone pic, sorry for the lack of quality
No hex nut was found on the entire assembly :thinking:
only adapters I bought from Mdocod had next nuts





I think FM has already addressed the issues by upgrading its versions. :candle:

Illum_the_nation said:

I think FM has already addressed the issues by upgrading its versions. :candle:

Click to expand...

I only bought my carrier last month and it was direct from FM. Unless he sold me an outdated version, the 12AA with the nut is the current one sold.

Also... I'm not sure if you thought I was charging when this all happened. I wasn't. The battery carrier was loaded with the Eneloops, but not connected to the charger in any way. The problem was totally independent of other hardware.

Well , let me add another story to this saga. I detailed this out in another thread marked TerraLUX TLE-300 in the led section of the forum . (I'm not sure how to post a link to that thread so I'm gonna recap it here)

I was upgrading my nephews 3D mag lite with the Terra LUX 300 module. A friend who is heavy into the lights and this forum had brought over a five mega pack for me to try. I had purchased some packs from MCDOD(?) who is on this forum.
I decided to try the five mega pack first and put in 9 new eneloops into the pack and put it into the flashlight. I verified the Terralux was installed correctly as I had tested it with the 3 D cells that were in the light originally and it lit up fine. I figured that the led module needed more voltage and was rated for up to 12 volts and was told that the module really needed 6 volts or more to make this module really shine. So hence the 10.8 volt pack was the way to make this happen.

I installed the pack and got nothing out of the light. I pulled the pack and carefully disassembled and then reassembled the pack making doubly sure I installed all the batteries correctly.
This time the light lit up fine and was brighter than on the 3Ds I tried it with originally.
I set the light on the side and assembled the mcdod pack which I felt wasn't as nicely made as the FM pak but should be suitable for his application.
I reached over to grab the light to test the second pack and the light is now hot and yes it was turned off. I opened the back to pull the pack and the first pull would not dislodge the pack. On the second pull the pack came out with the eneloops melted and swollen and leaking all inside the light. I disaasembled the pack and left it. I cleaned the light and reinstalled the 3 d batteries and now the module won't light with the 3 ds as it did before.
I install the Mcdod pack and it lights up again just fine. I hold the light while its on and everything is fine. I turn the light off and hold it for several minutes and its fine. I am still unsure about what happened so I pull the Mcdod pack and set it on the side and check it several times over the next few hours and its fine. Still being gun shy as it were I decide to disassemble the mcdod pack even though theres no issues with it.
I was told it was probably a short in the eneloops but all 18 batteries came from the same purchase from COSTCOs. so after seeing this thread I have to wonder if this is indeed what happened.
Since this is not my pack I'm goiing to wait untill I hear from my friend before I take it apart and see if that nut is what caused the problem.

this isn't good....now with added suspense
Mdocod's holders hint more "home made" than the ones FMs have, but they are very reliable in my experience, loading the batteries in long carriers without them falling out is tricky though

can someone here please post a pic on this "nut"?:candle:

Here's the pics. I put the nut back on just for this demo.

First, the negative end assembled as I received it.


Now, disassembled (still in order and orientation) showing the nut we removed.


Now, the "recession" the nut is supposed to rest in, without touching the aluminum. Notice it's only a little bigger diameter than the nut and not much deeper either.


If that nut touches any part of the aluminum it rests near, the circuit shorts and things get bad in a hurry. There needs to be something non-conductive between the nut and the aluminum.

It seems like the nut should be recessed into the nylon(?) disk.

quick solution IMO, replace the nut with a nylon nut.

(that's why I use nylon threaded rod through the center of my adapter design, here's no way for it to short out through the center of the adapter!)

Mr Happy said:

It seems like the nut should be recessed into the nylon(?) disk.

Click to expand...

That would probably work. At least then you'd have only one face that could contact anything and it'd be a little ways from anything else metal.

mdocod said:

quick solution IMO, replace the nut with a nylon nut.

Click to expand...

That probably is what I'll do. I hope FM changes the design to a nylon nut so nobody else has to fight this.

Instead of using a nylon nut, how about putting an insulating washer between the nut and the aluminum piece?

Funny thing is, I have never dismantled that end of the adaptor. I always thought of that end as a static fixture, and all the battery loading happens from the positive end. I'm quite sure the negative end, the one with the charging socket, is not intended to ever be removed.

Whilst I fully agree with the design improvement suggestions, I would also recommend checking for shorts with an ohmeter/continuity tester/battery and bulb before loading batteries, if the negative end has been disturbed.

Whoa!!! I never knew that the negative end can be dismantled. How were they held together? Glue?