Hunting for Fake Lithium Ion Batteries

Hey there guys! How's it going? I am back here in a quick instructable ( this was never planned btw.) where I would like to share my experience of revealing a fake 18650 Lithium Ion battery. And by the way, I gained this experience just 10~20 minutes earlier.

This is the fake lithium ion battery (rated for 2600mAh but delivered 1400mAh with my tests) I used in this reveal. My suggestion is to avoid ones that look like they have a thicker insulation on the body of the battery like these.

So basically, I was going through my shelf of batteries, checking them and charging those in need. When I picked up this 18650 battery of mine, I noticed that the protective film of it was a little torn. What surprised me was that there was a purple-ish layer under the already gray wrapping. This was odd as batteries like this revealed only the metal body of the batteries ( as far as my experience ).

As you can see, upon slowly stripping the plastic sleeve, we can see that it seems to be a relabelled/recycled battery.

No, I swear I did not change the batteries. This was the one under the "fake plastic protection". The label of this says that the battery is "1800mAh" but like I said, it yielded just 1400-ish mAh. So, I conclude that this is a used battery that has been re-wrapped and successfully sold to me.

You see, at that time, I wanted to make a 14.8V Li-ion battery pack. In order to avoid being scammed, I thought of testing a cell from the shop to see if it was real when it did. So, naturally, I bought 3 of them, knowing that they are real. I had high hopes. So, after making the pack, I charged and discharged it at 1A. It barely lasted an hour and half before the BMS kicked in. Measuring the voltage, I noticed that the real one (light violet) still had 3.9V while the three gray ones (the fakes) were at 2.7V. No wonder the BMS kicked in.

As you can see in the image, all three batteries hide the same battery inside. I was so disappointed as each costed 4$. The batteries in the inside (of the fake ones) were barely a dollar each.

Welp, to be honest, finding cheap, good and real 18650 batteries is like finding a lost diamond in an ocean. Hence, here are my suggestions.

Check their weight

A good 18650 battery should have something inside for it to be good right?

In my case, the real one weighed 45g whereas the fakes weighed 39g. (6g is enough for reducing 1Ah :0? )

Consider using LiFePO4

I have tested LiFePO4 batteries. Let me tell you, they are just awesome. A 32700, 3.2V 6Ah battery costing a bit more than 4$ turned out to be real. They are also cheaper. How? by energy to price ratio. 9.62Wh (the real 18650 battery's energy) vs 19.2Wh for around the same price? I'm definitely taking LiFePO4. These also have a longer shelf life than Li-ion. Yet, they are more safe than Li-ion. Even the voltage selection matches a 12v battery more than Li-ion. A 4S LiFePO4 pack gives 12.8V, (suitable replacement) wheras a 3S Li-ion pack gives 11.1V (already low for 12V) or a 4S Li-ion pack gives 14.8V (too high for 12V). I could talk a lot about LiFePO4, but what I'm trying to say is that, if you have the opportunity, better choose the LiFePO4.

Use 21700 or 26650 cells

If you are in need of the specific 3.7V/3.6V a Li-ion battery offers, you can use 21700 or 26650 cells. They offer way higher capacities and have the same voltage. These cells are less likely to be fake due to their popularity - Not many people use these.

Go for the branded ones

Batteries from brands like Samsung, LG, Sony, Panasonic, etc. are on their spots. They offer the capacity they mention. Though, I am not sure as I haven't tested them. Plus, they cost a lot.

Avoid the high capacity ones

As a kid, I have fallen to the scam of the cells that claim 9900mAh. So, now, avoid the batteries mentioned below:

1. Unbranded batteries above 2600mAh capacity.
2. Any cell that claims more than 3400mAh.

If you are choosing LiFePO4, ensure that the specified capacity does not exceed 6Ah (6000mAh).

It was really disappointing when something like this happens. A peaceful maintenance journey to a chaotic truth - revealing journey.

With this, I am signing off, saying to not be deceived..

Now, I try to keep all of these updated and as original as possible but still if something is off, please let me know in the comments and I will sort it out..