18650 and 21700 batteries - Page 1
Forum section: electronics / general

author: eeguy
author_rank: Regular Contributor
timestamp: September 28, 2024, 09:51:41 pm
content: Hello, for these two types of battery, there are only a few unknown brands on Amazon. Which brand is good? How come big name manufacturers don't make them? Are they more dangerous to work with compared with standard rechargeable batteries?

author: Siwastaja
author_rank: Super Contributor
timestamp: September 29, 2024, 05:33:13 am
content: Forget about it. They are not for end users / consumers at all. Of course big name manufacturers make them. But they also sell directly to professional customers only so they are harder to find from Amazon.These are not comparable to "normal" rechargeable batteries at all. They are raw materials you need to understand how to use.If you want to use them, first you spend a year or two to understand battery system design, then you either start a multi-million business so you can buy directly from Samsung/LG/Sony etc. Or if you can't do that, then you find as reliable as possible 3rd party "grey" source for these cells.

author: dietert1
author_rank: Super Contributor
timestamp: September 29, 2024, 07:23:44 am
content: In 2011 i used the LTC4053 for a device with a 18650 Li-Ion cell. It implements battery technology and is fairly easy to use and complete. All legal aspects were covered by reference to the LTC4053 data sheet.Regards, Dieter

author: Peabody
author_rank: Super Contributor
timestamp: September 29, 2024, 02:45:25 pm
content: You can order them from Digikey, which should be a reliable source.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 29, 2024, 03:05:45 pm
content: Quote from: Peabody on September 29, 2024, 02:45:25 pmYeah, just quite expensive but that's the price you have to pay for a reliable small scale source.

author: Peabody
author_rank: Super Contributor
timestamp: September 29, 2024, 03:20:03 pm
content: Digikey normally sells a 2500mAH unprotected flat-top 18650 from Tiny Circuits. The guy who runs Tiny Circuits was on the AmpHour podcast a while back, and apparently these are quality batteries. Digikey has no stock now, but you can order them directly from Tinycircuits.com for $6.95 plus shipping, or free shipping if you buy enough.https://tinycircuits.com/products/16850-lithium-ion-polymer-battery-3-7v-2500mah-cylindrical-cell-work-in-progress

author: ptluis
author_rank: Frequent Contributor
timestamp: September 30, 2024, 12:47:17 am
content: Quote from: eeguy on September 28, 2024, 09:51:41 pmMy friend Samsung, Panasonic, Sony and LG. Stick with those brands and you're ok. Forget all those Chinese and strange brands. Don't buy on AliExpress or Amazon or other marketplace. Even if they have one of the 4 previous brands I wrote, buy from a reputable supplier. Those sold on marketplaces are quality rejects for several reasons.BTW I'm on the EV business so I know exactly what I'm talking about

author: dietert1
author_rank: Super Contributor
timestamp: September 30, 2024, 01:32:29 pm
content: When looking for small Li-Ion cells i found the brand XCell. The cells are made by Rayovac who seem to be one of the big players, comparable to Duracell. Any experience?

author: squadchannel
author_rank: Frequent Contributor
timestamp: September 30, 2024, 01:36:06 pm
content: want to get a standard 18650 (not the high current type), a laptop battery would be a good choice.If you buy a genuine new one, of course it will be a well-known brand 18650.

author: coppice
author_rank: Super Contributor
timestamp: September 30, 2024, 01:41:08 pm
content: Quote from: ptluis on September 30, 2024, 12:47:17 amAll good advice, except its hard to follow. Its can be very difficult to identify a reputable and reasonable supplier. Looking around a few months ago all I could find were the usual low volume distributors asking stupid high prices, and obscure web sites offering big name brands at less extreme prices with nothing to inspire trust. The US seems different, but the reasonable suppliers I found there wouldn't ship outside the US.

author: eeguy
author_rank: Regular Contributor
timestamp: September 30, 2024, 01:45:40 pm
content: What so special about these two batteries to make them hard to find?

author: ptluis
author_rank: Frequent Contributor
timestamp: September 30, 2024, 02:18:11 pm
content: Quote from: coppice on September 30, 2024, 01:41:08 pmIn Europe nkon.nl is a good source, i bought tens of thousands of cells from them, and when I find one bad (because it could happen) they solve it fast. Besides new, they also sell refurbished ones. I bought some boxes of those for less demanding projects and they are fine, the only thing is the spots were the nickel strip was soldered.But since you are in UK you need to check first your customs rules about li-ion cells.

author: ptluis
author_rank: Frequent Contributor
timestamp: September 30, 2024, 02:19:30 pm
content: Quote from: dietert1 on September 30, 2024, 01:32:29 pmNot me, I only work with the 4 brands above

author: Siwastaja
author_rank: Super Contributor
timestamp: September 30, 2024, 02:32:39 pm
content: Quote from: eeguy on September 30, 2024, 01:45:40 pmThe potential of causing fire and thus reputational damage to the manufacturers if not used correctly, and complexity of use. You basically sign an NDA with the manufacturer to get full data and assistance in battery system design (mechanical, thermal and BMS). Then you get the license to buy cells directly from them.Or you bypass that process by going to suppliers, but not every supplier carry every possible battery, and some suppliers are more trustworthy than others.If you are a consumer, you buy consumer products of course. Li-ion battery packs on consumer market are device specific (e.g. laptop packs, camera packs, power tool packs, power banks...)Hobbyists are always a special case, if you are experienced enough that you can trust yourself then by all means find a 3rd party source (like nkon.nl in Europe) but you are on your own and no one said it's going to be easy finding this stuff. It's good that it's not too easy, if you don't have enough persistence to find the cells you definitely are not suited to design around them.

author: Kaylan
author_rank: Contributor
timestamp: September 30, 2024, 02:45:53 pm
content: Quote from: eeguy on September 28, 2024, 09:51:41 pmI started vaping to quit smoking years ago. Now i can't stop vaping. So i have a LOT of experience with 18650 batteries as these are essentially the type of battery that most vaping devices use. The best brands i have used are Samsung and Sony, to name a few. There are actually many decent brands. I have never had any problems with these batteries and i would say they aren't any more dangerous than any other battery when handled and used properly. Although, they do store a lot more energy than something like a AA battery. I have never had issues with bloating, leaking, ect. You can buy them online easily, although i mostly buy them from my local vape store. And its the same story with chargers. The only thing you need to watch out for is the cheap knockoff brands that aren't even close to their rated capacity.

author: coppice
author_rank: Super Contributor
timestamp: September 30, 2024, 02:49:30 pm
content: Quote from: ptluis on September 30, 2024, 02:18:11 pmInteresting. Their site has a "non-EU" page, and their conditions say "Prices are without VAT. You might have to pay VAT upon arrival in your own country.". So, I guess they'll sell and ship, and I would be liable on UK arrival.

author: ptluis
author_rank: Frequent Contributor
timestamp: September 30, 2024, 04:40:28 pm
content: Quote from: coppice on September 30, 2024, 02:49:30 pmI don't know how customs work in your country, do the math and see if worth the trouble or it's better to buy from local supplier. For big lots they are fine for me. Remember that this is a special cargo, considered dangerous so shipping is made by terrestrial carrier.Always test each cell independently, voltage and internal resistance before building any pack.