Which Lithium Ion Batteries To Get?

[electromateria]

Need lithium ion batteries for running various DC motors. I'm noticing prices range from $2-10+ per cell  Feeling a bit lost should I avoid the cheapest cells or are they decent?

https://www.aliexpress.com/item/32352951216.html
https://www.aliexpress.com/item/1005001632926149.html
https://liionwholesale.com/collections/batteries/products/dlg-grade-a-18650-flat-top-2600mah-battery
https://www.banggood.com/4PCS-MECO-3_7v-4000mAh-Protected-Rechargeable-18650-Li-ion-Battery-p-992723.html

Not sure what to get

[agehall]

If you are buying from AliExpress etc, it’s all a gamble anyway, so I’d just go with the cheapest you can find if this is the path you are going.

If you want something that works and where you know the specs, buy from a reputable source such as Mouser, DigiKey or any of the other usual suspects.

[Siwastaja]

The 4400mAh guys and the 4000mAh MECO are easy; 4000mAh cells in 18650 do not exist (well maybe in Samsung R&D lab) so they are with fake specs. MECO is also a no-name.

Definitely say no to no-names, UltraFires etc. Only buy proper brands, i.e., Samsung, LG, Panasonic, Sony... Buy cells with correct part numbers, you need to find the datasheet. Samsung INR18650-29E, -32E, -35E, -25R, -29Q, LG MH1, MJ1, Panasonic NCR18650B, and so on.

This only leaves you with the counterfeit problem.

Modern high-end large capacity cells, say Samsung MJ1 or Panasonic NCR B are "easier" since you can test them, assuming you have a capacity tester; cheap Chinese knockoffs have not reached similar capacities (they are in the range of 2000-2500mAh for "semi-good" cells) so you instantly see if they are fakes and can ask for money back.

Because you can't buy cells directly from the mentioned big names such as Samsung (you'd need to order in tens of millions $) nor you can't buy them from Digikey, the only way really is to find a somewhat reputable "light grey" distributor of such high-quality cells. Google around, look for forum discussions. Vaping and DIY e-bike communities know. They are some small companies people have dealt with and know they always got good cells. I use a local one here in Finland but that's likely not very helpful. But they get their cells from some semi-large German distributor AFAIK.

Aliexpress is a total gamble.

[tunk]

You could also see if you can find some laptop batteries, open them and see if the 18650s are OK.

[PeteH]

Your ceiling for buying top brand raw cells should be around $5/cell in low QTY...

Most power tool packs have good reputable cells and can be found for <$5/cell brand new... Used or failed packs from tools or laptops is another source. Don't use the cell that caused the failure (anything with low voltage - typically 1 cell going bad causes the entire pack to fail/stop working/charging)

Battery hookup is another source. Ebike/scooter packs are ok sources of used cells...

[strawberry]

https://youtu.be/xN50stJ2GBk
there is restored used sold as brand new
relabelled to well known brands but underperform

[electromateria]

Thanks for the really helpful replies!  You guys saved me a lot of wasted money   

[wizard69]

There is no simple answer here.    If you only need a few I'd go to digikey or another respected supplier and order from there.   Your lowest price is will likely be slightly under $5.  You will get known good batteries with data sheets.   You can even get protected batteries for reasonable prices.

Need lithium ion batteries for running various DC motors. I'm noticing prices range from $2-10+ per cell  Feeling a bit lost should I avoid the cheapest cells or are they decent?

https://www.aliexpress.com/item/32352951216.html
https://www.aliexpress.com/item/1005001632926149.html
https://liionwholesale.com/collections/batteries/products/dlg-grade-a-18650-flat-top-2600mah-battery
https://www.banggood.com/4PCS-MECO-3_7v-4000mAh-Protected-Rechargeable-18650-Li-ion-Battery-p-992723.html

Not sure what to get

If I remember right MECO is a TDK company and those batteries could be legit (needs checking).   Apparently Tesla is shipping a revised battery in some of its updated cars that is outperforming the old ones (Not really up on Tesla, just that they have been mixing things up battery wise).   I'm not sure if this reflects a new formulation or other improvements, but it is entirely possible that 4000mAh 18650's exist.   However if you can't find a part number and a matching data sheet from the manufacture it probably doesn't exist.   So what I'm saying is that those 4000mAh batteries might exists but there is a huge question related to what is advertised on line.

In any event the big problem with 18650's right now is demand.   That has pushed Tesla to use lithium-iron in some of its cars in China.    Prices are higher than ideal.

[mzzj]

Modern high-end large capacity cells, say Samsung MJ1 or Panasonic NCR B are "easier" since you can test them, assuming you have a capacity tester; cheap Chinese knockoffs have not reached similar capacities (they are in the range of 2000-2500mAh for "semi-good" cells) so you instantly see if they are fakes and can ask for money back.

Aliexpress is a total gamble.

I don't know what the chinese put inside these but I doubt it's original Panasonic. measured capacity is relatively close to stated: https://www.aliexpress.com/item/32848096612.html?spm=a2g0o.productlist.0.0.713348d4MQlypR&algo_pvid=6a4bfd1d-c418-4a51-a0ce-46157bee70b7&algo_exp_id=6a4bfd1d-c418-4a51-a0ce-46157bee70b7-9

So with some gambling you can get close to real 3400 mAh for 2 usd per piece from aliexpress. I wouldn't mind that much if real capacity is lower than advertised as long as they don't burn your house down. 

The cells that I got measured anywhere between 3100 and 3500 mAh and nothing on them looked like genuine Panasonic. Some were recycled cells with some grinding marks on terminals.

[perieanuo]

+1 for panasonic, used them in harsh environment and they performed.
buying frim ali, is gambling. the application you have decides what you buy, if you want low-cost battery and take the risk the battery dies after 6 months, your call.
cheap may be fine, but no for drill bits, batteries and stuff like this, where you risk is so big

[Peabody]

The guy that runs Tiny Circuits mentioned on the Amp Hour that he sells an 18650 through Digikey:

https://www.digikey.com/en/products/detail/tinycircuits/ASR00050/9808766

From his description on the podcast, these are high quality batteries.  They are flat top, unprotected.  I don't know about getting them to Canada.

[Rick Law]

Vap stores ( e-cigarettes, aka, vaping), would have been a good place for 18650's.  But: I've seen (heard of/read about) some rather good ones from vap stores and some dangerous ones.  When serializing 18650's for higher voltage, if things go bad, it can go really really bad.

With 18650's, if you want near-certainty that it is quality new cell, you have to get a new laptop battery pack from the laptop manufacturer.  Break the pack down then re-wrap the individual cells yourself.  Power tool battery packs are good ones to break down too, but I think (no actual evidence, just gut feels) laptop ones has better quality control.