I'm pulling amperage from my battery higher than its rated max discharge.

[Lin Swimmer]

Record scratch sound?

I'm using a protected 3.7V 18650 2600mah cell in an unregulated metal tube mod. The cell has a 1.5c rating at continuous discharge, and the mod's switch is rated for 3c. I've got an adapter and am using 2.0 ohm coils. That seems to be 2c. My plan for the future had been to go to 5V with a nimh at something like 3.0 ohms, which the calculator says is fewer amps, but my intention was to continue using my current set-up into the indefinite future, given that I've got a once a week charging ritual that I'm very happy with. I take readings of the cells' state of charge at least 4 hours off the charger before I use it, and then occasionally as I use it so that I can switch it out at about 3.6V.

My mod has two small vent holes that I don't take too seriously, and a Helix spring that I switched over to, which I'm overjoyed that it fit (dead simple to drop it into the mod without needing to clip or adjust), and that it wasn't (too) difficult to find, and of course cost nearly nothing. My cell is looser than it was; if I tap the mod with my finger or give it a little jostle I can feel/hear the cell give a little click around in there... but it seems firmly connected with its contact, and hasn't misfired over the couple thousand firings I've given it since getting the springs in there.

So... situation normal? I'm aware of the IMRs, haven't used them, and would like to use the cells I've got for a couple hundred more charges before I think much more about switching to something else with different chemistry and no protection circuit.

Provided that people concur that I'm operating well enough within reasonable safety margins.

I'm also unsure of what my current cells will do in the event of a dead short. Anyone have any idea how that manifests?

 

[Rocketman]

Your 3.7 volt cell and the 2 ohms will give you less than 2 amps. 1C for a 2600 cell is 2.6 amps.

You are not overloading the cell.

Protected cells have a thin metal strip running under the wrapper from the positive cap down to the protection board. This is how the protection board senses cell voltage. The bottom negative contact is not the same as the shell of the cell.

Follow so far?

The protection board has three contacts.
The shell of the cell, The negative bottom contact, The Positive strip.

If your mod is metal, a small nick or cut in the plastic wrapper can allow the cell to contact the case.
Now 2 out of three contacts of the protection board are in contact with the shell case.
The bottom with the spring, and the shell of the cell touching the inside of the mod case.
The protection board has now been defeated.

If the plastic wrapper gets nicked over the positive strip, the cell will short out to the case.
You may end up in the news.

Cut a dollar bill to fit inside the mod case to keep the cell from touching the sides. and inspect all cells each and every time you touch them.

 

[Rocketman]

Does the bottom of your mod come apart?
Like a metal plug?
Is it like really really tight?
Like tighter than the top?

 

[Lin Swimmer]

Was going to make a joke about cutting down dollar coins to fit into my mod, but instead I'll just thank you for the tip and go cut up $2. Does the cloth in a dollar make it less conductive than normal paper?

I think you taught me how to read the state of charge, actually. Hello, and thanks, and thanks again. You really seem to know your stuff, and explain everything clearly.

Can you tell me how you calculated my c rating? I don't think I even realized that would vary based on a range of mahs.

 

[Rocketman]

Joking about dollar. Use a playing card.

2600mah is 2.6 amp hours.
1C is the capacity rating.
If your cell is rated at1.5 C that's 1.5 times the 2.6
2 amps (3.7 volts divided by the 2 ohms is less than 2 amps) is OK for that cell.
A 2 ohm carto is OK for just about ANY 18650.
It's when you get into the Low Resistance stuff, or Boost mods that cell start to have problems.

Watch the cell wrappers. Examine the cells often. Got a voltmeter? If not get one.


You aren't making fun of my flashlight mods with a Quarter for the front end are you?

Only use damaged coins. And for those know it alls (who me? ) coins ain't currency per the US Treasury. Just don't melt them down for scrap metal. That's against the law.
and don't try and melt down a dollar bill.

 

[Lin Swimmer]

The entire bottom 2/3rds of the mod is a single piece of aluminum, and doesn't come apart.

The only tightness in the entire mod is that I have to screw down the 510 to 510 adapter all the way to get it to not wiggle, and it still does very slightly on one unit but not its twin.

 

[VapoVamp]

Hi Rocket, SOOOO! glad I found you along with this problem. About 2 months ago I recieved an E-Power w/2 18650's. I was inspecting both before I put them on charge and found a minute rip in the blue encasing, Now, I'm new at batt mods, but my gut told me not to use that one in my metal tube. Whew, now I know why...thanx Rocket for your vast knowledge. Oh, can I use an athletic type cloth tape. (I keep no cash, Tax Man gets it). Again, I love following your wisdom on all things Vaping, fore you've helped me more than I can say. KUDOS! See you in the Vapehaze

You 3.7 volt cell and the 2 ohms will give you less than 2 amps. 1C for a 2600 cell is 2.6 amps.

You are not overloading the cell.

Protected cells have a thin metal strip running under the wrapper from the positive cap down to the protection board. This is how the protection board senses cell voltage. The bottom negative contact is not the same as the shell of the cell.

Follow so far?

The protection board has three contacts.
The shell of the cell, The negative bottom contact, The Positive strip.

If your mod is metal, a small nick or cut in the plastic wrapper can allow the cell to contact the case.
Now 2 out of three contacts of the protection board are in contact with the shell case.
The bottom with the spring, and the shell of the cell touching the inside of the mod case.
The protection board has now been defeated.

If the plastic wrapper gets nicked over the positive strip, the cell will short out to the case.
You may end up in the news.

Cut a dollar bill to fit inside the mod case to keep the cell from touching the sides. and inspect all cells each and every time you touch them.

 

[Lin Swimmer]

We keep cross posting, and I'll keep cutting up money.

That's what I mean; I have a voltmeter because I saw that you recommended one gets one.

 

[Rocketman]

High Temperature Kapton tape, Black electric tape, clear packing tape, scotch tape, in that order of preference.
Cloth tape is thick. Some mods don't have that much room.

Here's a 14650 that got too close to an e-power 14650 mod.

See the metal strip exposed under the MELTED PLASTIC?

 

[VapoVamp]

Ohhhhhh, close call. Thanx Rocket I'll go unload my bottom kitchen draws for some...don't know what Kapton tape is...but, I'm pretty sure I have some black stuff....somewhere?Oh, yea bottom draw, hope I can get it open....

 

[VapoVamp]

DA...N!! Now I have to learn how to attach those meters????

We keep cross posting, and I'll keep cutting up money.

That's what I mean; I have a voltmeter because I saw that you recommended one gets one.

 

[Rocketman]

Using a meter on your batteries, cartos, charger, etc. is just like glancing at the temperature gauge on you dashboard every so often, just to get an idea where "normal" is. Any change and something could be wrong.

 

[Lin Swimmer]

I had a CE2 clearo die unexpectedly, and it read 0 resistance. I threw it away. I always wanted to ask Rocketman if that was a 'dead short.'

So, no, then. That was just a dead coil.

[Also... I use my playing cards as bookmarks, and don't want to just cut up everything in my house... can I keep the dollar bill in there while I figure out where to buy good tape? I have a feeling good tape is going to be about as overpriced as my silly Radioshack meter.]

 

[VapoVamp]

O.k. No black tape...I did find my Miracle grow spike for my tropical trees.....If the cloth sports tape works...is that alright to cove the cut?, and where and what kind of meters do I need? Do you have a vid on how to use them? I'm just full of ?'s .....

 

[Rocketman]

The cloth tape will be fine if the cell still fits in the mod. It's for keep things from touching together.

Cheap digital multimeter. $10 (or less)
I think their is a tutorial, or youtube vid, search DVM + e-cig
Their is also a screw on one for measuring mod volts, but I like the ones with multiple functions and test leads.

NAP TIME,

Glad you guys are 'thinking safe'.

Rocky

 

[VapoVamp]

Thanks Rocket!!!! Power naps are the bomb

 

[Shortstuff116]

If you're using 18650's you can use a paper roll for dimes to act as a sleeve inside your tube to keep the outer "skin" of the battery from contacting the tube itself. An empty "dime" roll is a perfect fit.