Need suggestions for this small battery and posible usage ideas.

Thread Starter

Roxx.R

Joined Mar 14, 2023
47
Hello friends, so now i have came up with this small battery and its small circuit. These are two identical circuits and i have numbered it 1 and 2 in the images attached.

This circuits are from two identical vapes, it had this rechargeable battery and a type C input for charging the battery. i think the led light goes off when the charging is done. There are two other short wires but don't know where they would get connected and what's its use. Its doesn't have any markings except we can see number 4 on the battery. We don't even know what type of battery it is.

1st Circuit: it has a filament in the circuit. The filament is open and lights/burns up when directly connected to the battery.

2nd Circuit: this one just has the battery and the circuit board with input type C, extra parts are lost. Observe that the battery has circular layers inside which are visible on its sides.

So, my thoughts are, can i connect both batteries in parallel, connect it to only one circuit, charge it, and then make it usable for something if possible.
Another question i have is, can i make use of the filament for something, that powers up like a naked bulb/led? I don't smoke or i could make an electric cigarette lighter!! I haven't turned it on for more than 2seconds due to the fear that it would burn to ash.

For now i have kept it for charging and later i will check the voltage. I request for your ideas and suggestions on what i can do with these.
 

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Ya’akov

Joined Jan 27, 2019
9,237
The filament isn’t going to be useful unless you happen to have a project that needs a heater with its characteristics. You can save it, and if you recall that you have it, it may prove useful some day.

The Lithium Ion cell and the charger board are more useful. You can use them to power anything that needs the ~3.7V such a cell provides, and the board can keep it charged.

It’s a nice, small form factor. It might be fun to get a cheap boost converter designed to provide 5V from a lithium cell and make a tiny battery bank for a phone or whatever. Of course that cell is going to have poor capacity but it would work in a pinch to make some phone calls or send some SMSs.

Paralleling the two cells you have would give it more capacity but be careful. Since there is no balancing electronics you have to be sure both cells are at about the same voltage before connecting and charging them together. You can just charge them both up with the board which will shut off at a particular voltage.

Measure them to be sure, then connect them together. The cells used in vape gear are generally capable of potentially dangerous high current so take care not to short them.
 

Thread Starter

Roxx.R

Joined Mar 14, 2023
47
The filament isn’t going to be useful unless you happen to have a project that needs a heater with its characteristics. You can save it, and if you recall that you have it, it may prove useful some day.
Thanks for the idea.. i can use the filament to heat aquarium water when its winter. i could use a small glass case to cover it and dip it half way in water at the surface. I used to make aquariums and keep fishes few years ago, but most relatives and friends wanted it almost free so i stopped making it.. but i can make one aquarium again for myself.

The image with number 2, that cell is showing 0.06V.. and number 1 is showing 2.49V ... I think it showed higher volt before but i don't remember.. i will charge one at a time and check. Thanks again.
 

Ya’akov

Joined Jan 27, 2019
9,237
Thanks for the idea.. i can use the filament to heat aquarium water when its winter. i could use a small glass case to cover it and dip it half way in water at the surface. I used to make aquariums and keep fishes few years ago, but most relatives and friends wanted it almost free so i stopped making it.. but i can make one aquarium again for myself.

The image with number 2, that cell is showing 0.06V.. and number 1 is showing 2.49V ... I think it showed higher volt before but i don't remember.. i will charge one at a time and check. Thanks again.
Throw away the cell that is reading .06V! Any Lithium cell that goes below 1V is dangerous. They begin to for dendrites which are conductive and can short circuit the cell internally. This causes a great deal of heat, and the electrolyte in a Lithium Ion cell is highly flammable. They become flamethrowers and can’t be easily extinguished. It is not worth the risk.
 

WBahn

Joined Mar 31, 2012
30,252
Thanks for the idea.. i can use the filament to heat aquarium water when its winter. i could use a small glass case to cover it and dip it half way in water at the surface. I used to make aquariums and keep fishes few years ago, but most relatives and friends wanted it almost free so i stopped making it.. but i can make one aquarium again for myself.

The image with number 2, that cell is showing 0.06V.. and number 1 is showing 2.49V ... I think it showed higher volt before but i don't remember.. i will charge one at a time and check. Thanks again.
I'd be rather surprised if that filament is going to be very good for heating aquarium water. It's designed to get very hot, yes, but it's not designed to actually deliver a lot of heat. It's also not designed for continuous use, but rather very brief surges of just a few seconds at a time.
 

Ya’akov

Joined Jan 27, 2019
9,237
Oh.. i didn't knew this in detail.. Thanks @Ya’akov .. i have kept that 0.06V cell aside and safe.
To clarify something: Lithium Ion cells that have formed dendritic shorts are not dangerous unless you try to charge them. That’s when they overheat and ignite. Sometimes they will successfully charge before a short of sufficient ampacity causes the fire.

There are many videos of, in particular, vape pens emitting jets of flame. These are almost always the ”high performance“ modded type, sometimes using unprotected cells to avoid current limiting—a recipe for disaster. On the other hand, for a short time Samsung flagship phones posed the same danger.

A solution is LiFePO4 (Lithium Iron Phosphate) cells. They have a huge advantage in that unlike Li-Ion cylindrical cells, and LiPo (Lithium Polymer) pouch cells, the electrolyte¹ used is not flammable. From the point of view of maximizing sales and profits, though, they have the distinct disadvantage of lower energy density² and somewhat higher cost.

The lower energy density means a larger battery for the same capacity as a conventional Lithium secondary³ cell, which means fatter phones and computers—a definite no-no in the current market. The added cost, which is only a couple of dollars in an item cost hundreds or thousands may seem easy to absorb but that’s not how things work at an industrial scale.

If you manufacture 10 million of something and your profit which you count in two-digit dollars shrinks by some largish single digit number, that hurts. If you raise your price, you suddenly cost more than the slimmer or longer running alternatives. LiFePO4 batteries are not (yet) understood well enough to be a selling point. So, you can see why a profit-driven company would eschew them.


1. An electrolyte is a medium through which current flows in a cell. It can be liquid, gel, or solid material. In Li-Ion and LiPo cells, it is a very flammable liquid.

2. Energy density is a measure of the capacity to store energy per unit volume of the storage. It can describe cell capacity, or things like fuels. The energy density of Lithium Ion cells is extremely high. This is one reason they are so dangerous. When they discharge into a low resistance they can shed their chemical energy as electric current at scary rates.

Some Li-Ion cells can produce on the order of 10s of amps when shorted. This is thanks to a very low ESR (Equivalent Series Resistance) which is a measure of the resistance presented by the battery to the flow of current. For Li-Ion cells, it is measured in milliohms, that is, 1/1000Ω.

An ampere is one coloumb-per-second, with the Coulomb being a measure of charge. You can think of it in terms of electrons, like a fluid—but don’t use that analogy past this concept, it fails miserably very quickly.

The ampere is 1C/s past some point in the circuit. If we take the nominal voltage of the cell to be 3.7V, and for discussion we adopt an ordinary “high discharge” cell that can produce 5A, the math gives us 18.5W. The Watt is a measure of power. To get an idea of that that represents, watts can be directly converted to horsepower, and that would be 0.025hp.

This is why cells are placed together in batteries. They are arranged in groups to get the voltage and current numbers for the job. An “18V” tool battery is 5 cells in a series. This “5S” arrangement is generally good for a capacity of up to 5AH (Amp Hours) which is very roughly 1A for 5 hours or 5A for 1 hour, etc.

This is not always exactly correct since there are practical limits on discharge rate so look for the discharge rate specification while will say something like “at 1A”. This doesn’t mean the battery can’t produce more than 1A, it means its AH specification will be derated at higher discharge rates, and possibly increased for lower ones.

The reason for explaining all this is to describe the amount of energy stored in the battery and its cells. Controlled discharge is one thing—think about a drill running on a 5AH 18V pack—some have the potential to break your wrist if you are not careful. How long can you run that drill at wrist-breaking power? Probably for 30 minutes or so. That is with the controlled discharge.

What if all that power were released in a much shorter time, like in the short circuit case? Remember that watts are directly correlated with heat! Let’s say it won’t be a fun time if you are holding it, or it is in your tool bag…

3. A secondary cell is a rechargeable one—a primary cell can’t be recharged. The distinction arises from chemistries that immediately produce current when assembled, that is, they are a primary source of power; and those that must be charged but can store a charge from another source.
 

Thread Starter

Roxx.R

Joined Mar 14, 2023
47
@Ya’akov ..thanks for your efforts to explain me but this is too much for me to understand. I will need to read it again and again..

Just a quick question about a powerbank i am making... Can i connect li-ion 18650x8 parallel cells 3.75v and li-polymer cell 3.68v to a single power bank circuit? Let me attach a picture. Or should i create a new thread with more details about it.
Thanks again.
 

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Ya’akov

Joined Jan 27, 2019
9,237
@Ya’akov ..thanks for your efforts to explain me but this is too much for me to understand. I will need to read it again and again..

Just a quick question about a powerbank i am making... Can i connect li-ion 18650x8 parallel cells 3.75v and li-polymer cell 3.68v to a single power bank circuit? Let me attach a picture. Or should i create a new thread with more details about it.
Thanks again.
Starting a new thread might be helpful to others who are searching of information about the same thing. I will let you know, though, that there are complications with multi-cell battery packs when it comes to charging. You should be sure you know what is going on before you connect several cells together.
 

Thread Starter

Roxx.R

Joined Mar 14, 2023
47
Starting a new thread might be helpful to others who are searching of information about the same thing. I will let you know, though, that there are complications with multi-cell battery packs when it comes to charging. You should be sure you know what is going on before you connect several cells together.
Thanks, i will start a new thread about it.
 
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