Help diagnose battery problem with LG INR18650MJ1

I have 4 new cells and a brand new light. I pulled 4 of these from my TK75 today to top off the charge. When I put them on the Xstar VC4 charger two of them read 3.5 volts, and the other read 4.15 volts, and one would not read or charge at all, it is dead. When I first got the light, I charged them all at the same time till full with no problems. What is going on here? Shouldn't they discharge mostly the same?

ateupwithgolf said:

I have 4 new cells and a brand new light. I pulled 4 of these from my TK75 today to top off the charge. When I put them on the Xstar VC4 charger two of them read 3.5 volts, and the other read 4.15 volts, and one would not read or charge at all, it is dead. When I first got the light, I charged them all at the same time till full with no problems. What is going on here? Shouldn't they discharge mostly the same?

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Is it a protected cell?

If so, you might have tripped the PCB circuit.

If they're naked cells, try another slot, or another charger.

What does that cell read with a digital multi-meter DMM?

Chris

These are unprotected button top cells. I got them from Mtn Electronics.

I tried both another slot and my Nitecore i2 charger and it would not read on it either.

I don't yet have a multimeter.

ateupwithgolf said:

These are unprotected button top cells. I got them from Mtn Electronics.

I tried both another slot and my Nitecore i2 charger and it would not read on it either.

I don't yet have a multimeter.

LG 18650MJ1 3500mAh - Button Top Unprotected

LG18650MJ1-BT

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Well, I've never taken apart an 18650, so I don't know what could have failed internally on a new cell and there's no PCB to fail on it.

Do you have a single 18650 light that you can try it in?

Otherwise, I'd just contact Richard at ME and put a link to this thread in the Email and have him send out another one.

He was pretty good to me when my VP2 was recalled and my DQG Tiny Triple went up in smoke, literally.

Chris

Ok, now this is really weird. I took your advice and put the cell in question into my zebralight SC62 and it works perfectly.

I then tried putting it back into all 4 different slots in the VC4 and it would not read. Then I tried it again in the i2 charger and nothing.

Why would it work in my light and not my chargers?

I don't know if this helps but regarding the other 3 cells that I had charging.

The one that read 4.15 volts at the start said full at 260mAH. At the same time the one was full the other 2 cells both read around 410mAH and 3.6 volts, and they are of course still charging.

I have no idea but I would contact the supplier about what to do next. You really need a multimeter though.

I would not try to do anything more with that cell though. It isn't worth having it vent on you. I wouldn't even want it in my home. I'd bring it to the fire station. I doubt mtn electronics wants it back.

I tried it also in my P12GT and it works in that one too, very strange! I will take your advice and retire it.

ateupwithgolf said:

I don't know if this helps but regarding the other 3 cells that I had charging.

The one that read 4.15 volts at the start said full at 260mAH. At the same time the one was full the other 2 cells both read around 410mAH and 3.6 volts, and they are of course still charging.

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3.6v should be more than 410mAh to full. Closer to ~1500mAh, IMO.

Send the one back for sure and watch the other three.

Chris

May be you have a bad charger?

Just check the voltage of each cell with the p12gt. If i am not mistaken it has a voltage count.

So... longshot but because unprotected cells are supposed to be used for industrial purposes (building battery packs etc...) and not loose, I've found the positive and negative contacts are really really soft and frequently get slightly dented with regular use. This one battery might be able to make contact when springs are used (such as in a flashlight) but might not properly touch the positive contact (which is usually fixed in chargers) for charging due to slight physical damage. Take a look at the positive contact of the flakey battery to see if, perhaps, it is dented in.

scs said:

May be you have a bad charger?

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I used both the Xstar VC4 and the Nitecore i2, same story.

ChrisGarrett said:

3.6v should be more than 410mAh to full. Closer to ~1500mAh, IMO.

Send the one back for sure and watch the other three.

Chris

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What I was trying to say was that when the one battery was reading full I had put 260mAh into it.

The other 2 batteries were reading 410mAH AT THAT TIME, but were only 3.6 volts. I was just showing the difference in voltage between the 3.

I thought that batteries should be all needing around the same charge, but there was a big difference between them.

I emailed Richard at Mt. Electronics. He said it was very strange on an unprotected cell (Chris Garrett concurs) and was going to send me a replacement. He told me to discharge the cell all the way down and then dispose of it.

As for the difference in cell voltage, he said that it had to be that one cell was not making contact in the carrier of the light. It is a modified tk75vnQ, so I know something was done to the carrier. I have more cells, so I'll see if it repeats in those.

I wouldn't even want to discharge it. Certainly don't do it indoors nor in a flashlight you care about. Recycle it. A bad cell can go REAL bad at any time. I am more careful than most but why risk your home or health at all?

recDNA said:

I wouldn't even want to discharge it. Certainly don't do it indoors nor in a flashlight you care about. Recycle it. A bad cell can go REAL bad at any time. I am more careful than most but why risk your home or health at all?

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Good point I'm not messing with it.

Wanted to update this thread: I sent my cells in to Richard at Mtn Electronics. I had one bad 3500maH "GA" cell and one bad LG INR18650MJ1 that wouldn't read on my chargers. Richard said that the GA cell wouldn't read on his charger, but the MJ1 did and it read 4.30 volts. He said something might be wrong with my charger. However, I tried the bad MJ1 cell on both the Nitecore i2 and the xstar vc4 and it wouldn't read. How do you check to see if your charger is bad?

ateupwithgolf said:

Wanted to update this thread: I sent my cells in to Richard at Mtn Electronics. I had one bad 3500maH "GA" cell and one bad LG INR18650MJ1 that wouldn't read on my chargers. Richard said that the GA cell wouldn't read on his charger, but the MJ1 did and it read 4.30 volts. He said something might be wrong with my charger. However, I tried the bad MJ1 cell on both the Nitecore i2 and the xstar vc4 and it wouldn't read. How do you check to see if your charger is bad?

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Is it the same slot that is giving you problems?

You have a bad GA cell, which Richard has confirmed, but 4.30v for the MJ1 is high on even his charger?

4.30v is too high even on his charger, if I'm reading that correctly?

Chris

ChrisGarrett said:

Is it the same slot that is giving you problems?

You have a bad GA cell, which Richard has confirmed, but 4.30v for the MJ1 is high on even his charger?

4.30v is too high even on his charger, if I'm reading that correctly?

Chris

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Yes, Richard said the GA cell is indeed bad, but that the MJ1 will read on his charger but read 4.30 volts. That same MJ1 cell would not read on either my VC4 or nitecore i2 charger. He said I may have a bad charger, but I don't have that problem with any other cells to my knowledge so I don't know what to think..

I also have a new LUC4 charger but didn't have the bad cell then so I'll just stick with it.