21 July, 2015

The Li-ion 18650 for sale on the Internet: There are more false than legitimate

When I started acquiring Li-ion batteries 18650 back in 2012 to restore some packs, there were still no stores in Spain that had them and I started to import them through Chinese pages like DX.com, aliexpress, Ebay, etc.
Note: The reference "18650" refers to the shape and dimensions; 18 is the diameter in mm, 65 is length and 0 indicates the shape; in this case cylindrical.
At first I was confident and I trusted the ads in some extent, I knew the false capacities of some NI-MH before, where manufacturers also indicated many times more capacity than real, so I was prepared. I compared, and bought cheap, but not the cheapest, high capacity (announced) batteries, , and hoped that there would not be much difference.
This problem is very well explained in Energizes or Bateriasdelitio.net , which echo the deceptions of Chinese "smart" guys.
I was wrong. I came to ordering (ouch!) For 3 €/unit. 18 batteries "Fandy-FIRE", the "manufacturer" marked them as 3600 mAh capacity, when in fact they only had 800 or less! When they arrived the first thing that struck me was how little weighed; the larger capacity usually weigh 47 grams / unit, when these did not reach the 30 g / pc., although some manufacturers are "approaching" the weight of the good ones filling them with materials as diverse as flour!

These publicized 3600 and do not reach 900 mAh actual

I quickly realized of the cheat... and after leaving a negative feedback (which did not appear ever published of course), I chose to buy others that had good reviews.
DX.com has the "unethical" practice of not publishing very negative comments, so if an item of dubious quality has no comments ... suspect of it!
It is best to order 1 for testing, check it with a charger that measures amps, and then buy more, or consult websites that compare them (there are a lot given the popularity of these portable battery chargers for mobile, LED flashlights, electronic cigarettes, etc.)

I bought some of the following "Trustfire" of 2500 mAh, which actually did not reach 2000 mAh by a bit, and that eventually I could see that they were of low quality, because they degrade very quickly. I still got much better results than the previous ones:

Buying quality Li-Ion

After that I bought the Trustfire "MVP" recommended by the own page  with good reviews; They were more expensive but really out cheaper in price capacity, and also they came with a chip that protects them against overload and over-discharge, which lengthens its life much (and design rocks!).
But if you need to put some on a pack without PCB load control (placing a entire battery BMS controlled) then I would advise the Samsung , guaranteed capacity of 2600 mAh to 3 € / each (plus VAT customs). And if not, these other with PCB, very good .

Keep in mind that  no current 18650 lithium / cobalt battery can have more than 3400 mAh per unit, by technological constraints (thickness of the sheet of lithium and electrolyte), only a few models of Panasonic Japanese (and other Samsung I think) that can be charged to 4.3V can held that energy.

¿5300 mAh? What are you telling me ...

So very careful when buying this type of battery, because even Amazon sell batteries with false capacities / quality.

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