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Author Topic: 18650 batteries ?  (Read 596 times)

phillnjack3

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18650 batteries ?
« on: May 21, 2021, 08:10:34 pm »

not knowing anything about brushless motor batteries
are 18650 batteries any good for brushless motors ?


are they the same as lipo's ?




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Subculture

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Re: 18650 batteries ?
« Reply #1 on: May 21, 2021, 09:01:26 pm »

Brushless work on the same batteries as brushed motors, however to get the best punch out of the set-up it's folly to use anything other than lithium batteries.

18650 are Ssightly lower cell voltage than lipo- 3.6v instead of 3.7v usually labelled as Lithium-ion.

The 18650 refers to the battery dimensions 18mm diameter and 65mm long. They vary hugely in capacity and current capability. The best cells allow up to about 30A continuous, although for best life you should halve that rating to around 15A continuous and for a model of the size you have I would recommend a minimum of a 4 cell and preferably 6 cell (22.2v) set-up. That will give you over 300 watts of power to tap into.

e.g. https://eu.nkon.nl/sony-us18650vtc4-flat-top.html

Tug Fanatic

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Re: 18650 batteries ?
« Reply #2 on: May 21, 2021, 09:14:02 pm »

I understand that the maximum capacity for a 18650 is around 3450mah. It might be that they can now make them larger but I would be cautious about some of the capacities advertised. Look at what the big manufacturers like Sanyo & Panasonic list (around 3450mah) & then wonder about those that you have never heard of that list capacities of up to 10000mah.

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cos918

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Re: 18650 batteries ?
« Reply #3 on: May 21, 2021, 09:37:57 pm »

all you need to know about thoes questionale chines 18650 batteries from one of you tubes best testers.

John
(5) Will China's 18650 Battery Beat LG, Samsung, Sony & Panasonic? Let's find out! - YouTube

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HMS Invisible

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Re: 18650 batteries ?
« Reply #4 on: May 21, 2021, 11:15:56 pm »

not knowing anything about brushless motor batteries
are 18650 batteries any good for brushless motors ?


are they the same as lipo's ?
There is (or used to be) more choice in chemistry in 18650 than for familiar RC stick packs. Hence the 3.6/3.7 figures you see.

Note the C rating is much lower in cylinder cells than stick packs but it is still far ahead of NiMH & NiCd types. The C rating where I think Subculture's folly term is spot on. NiMH advocates should think twice and compare 6 or 7 cell NiMH packs against equivalent 2S Lipo packs with a 6volt cutout. I've seen it many times, demonstrated to non competitive fast electric users that they may as well decommission their NIMH batteries if they don't use specialised chargers and do the performance checks on, so called, high discharge NiMH packs.

21700 is another popular size and it beats me why diy battery builders prefer to make 40% more spot welds in 18650 ebike packs as if there aren't enough other drawbacks. The present (@ 21/May/2021) shortage means this wholesaler is out of stock on Samsung 18650.

Poundland powerbanks will get you cheap 2 Ah cells for 2 with USB charging. Power tool packs will give you 5s and bms. There's the mention of your choice if you were to make 18650 Lipo packs: balance lead or BMS.
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phillnjack3

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Re: 18650 batteries ?
« Reply #5 on: May 22, 2021, 12:27:54 am »

so best to just stick to liopo'sand leave the 18650 batteries where they are.
saves a grumpy old fat bloke climbing a fence to get them .....
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Subculture

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Re: 18650 batteries ?
« Reply #6 on: May 22, 2021, 09:39:24 am »

18650 are Lithium batteries. There are quite a few different types of chemistries for Lithium batteries, the ones used a lot in the flat cell type packs commonly sold to modellers tend to favour maximum current output with minimum weight, but they don't always have the longest cycle life or the most stable chemistry.

If you're new to lithium battery technology, the choice can be a bit bewildering, but with a bit of experience you can quickly make a choice.

malcolmfrary

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Re: 18650 batteries ?
« Reply #7 on: May 22, 2021, 09:41:51 am »

18650 refers to the physical size.  18mm diameter, 65.0mm long.  It is possible to buy NiMH cells that size as well as LiPo and no doubt other chemistries.  I have bought both NiMH and LiPo.


LiPo sellers claiming 9000mAH are probably not worrying too much about the number of zeros in the description.
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Subculture

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Re: 18650 batteries ?
« Reply #8 on: May 22, 2021, 09:50:19 am »

I'll be more specific 18650 are the vast majority of the time, Lithium based chemistry, and the ones I linked to are Lithium based and a good cell.

phillnjack3

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Re: 18650 batteries ?
« Reply #9 on: May 22, 2021, 12:05:44 pm »

The batteries i am refering to are fitted in the rental scooters that are now scattered all over the place.
seena  couple get vandalised and see a battery pack chucked over a fence..
Looks like a lot of them what from what i can see 9 big fence in the way stopping me getting closer look.


they might be knackered due to being ripped out and chucked, but just wondered if they are good things for motors.


from what ive seen about the dangers i dont think i would like to play with a pack that could be badly damaged.



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Martin [Admin]

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Re: 18650 batteries ?
« Reply #10 on: May 22, 2021, 12:09:27 pm »


Fixed battery pack for scooters etc, are OK, they usually have circuits to limit power output, discharge limits  & charging built in, BMS (Battery Management System).
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kinmel

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Re: 18650 batteries ?
« Reply #11 on: May 22, 2021, 01:32:40 pm »

This type of cell construction is the future, various sizes are now built up to create large battery packs, Tesla's car packs use 7104 cells of a 4680 version.

The world's largest factory makes those batteries, but there is a DiY option...          https://www.youtube.com/watch?v=PenPYwa00CA
« Last Edit: May 22, 2021, 02:19:50 pm by kinmel »
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16-21

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Re: 18650 batteries ?
« Reply #12 on: May 22, 2021, 02:11:46 pm »

You could also have a look at
21700 batteries if space permits?
Or
Look for Headway 15ah?
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Subculture

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Re: 18650 batteries ?
« Reply #13 on: May 22, 2021, 02:19:36 pm »

18650 is a popular size as they're used in so many different things. Consequently they're quite cheap.

The larger sizes tend to be more expensive with a bit less choice in capacities and c ratings.

Nothing wrong with using salvage cells IMO. Just snip the pack apart and test each cell with a voltmeter to see if the voltage is okay. Good cells should read somewhere from about 3.6-4.2v per cell.

Tug Fanatic

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Re: 18650 batteries ?
« Reply #14 on: May 22, 2021, 04:27:45 pm »


...
e.g. https://eu.nkon.nl/sony-us18650vtc4-flat-top.html
Interesting link. Unless you are going to buy a lot of batteries the carriage costs are horrible to the UK (but reasonable elsewhere) and they have a specific warning about delivery taking a long time to the UK because of the import problems and delays. I had thought the bad delays were on exports to Europe but it appears that they are on imports as well.

What a mess we are in.
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phillnjack3

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Re: 18650 batteries ?
« Reply #15 on: May 22, 2021, 07:46:33 pm »

quicker to buy from china than buying from usa
most chinese stuff they dont even bother with.
stick a label on saying usa or australia and the customs are all over it..
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roycv

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Re: 18650 batteries ?
« Reply #16 on: May 31, 2021, 05:17:21 pm »

Thanks cos918 for the heads up on the batteries.  It answered all my questions. My initial interest was sparked off by buying two torches each with a single 18650 cell, very bright work well.

 It is apparent that if you check the weight in grams of the cells then the amp hour capacity can be checked against it.  I note that Component Shop stock 2600mAh cells with a high discharge rate and weigh 48 grms per cell. 

The rather enthusiastic Chinese claims have batteries in the 34grms area and were rated in the video as showing 12% of rated capacity.

The moral is do not buy the China versions but Japan and Korea came out well.  Charging is best left to an intelligent charger and not letting them discharge fully is essential.  The information given was that the cell can close down inside and need a special charger to get going again.

Some of the cells have internal protection and this makes the physical length 3mm greater, which might be a squeeze for the standard spring holders.  The specification shows whether they are protected cells or not.

So what about my 2 torches?  I weighed the batteries and although the cells are marked 3000mAh I weighed them and yes you have guessed it, just 36 grms!

Looks like the old, old story "You get what you pay for"!
regards
Roy
 
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