Why are 18350 so low in capacity?

10 posts / 0 new
Last post
L4M4's picture
Last seen: 7 hours 11 min ago
Joined: 12/08/2013 - 13:43
Posts: 1140
Location: Germany
Why are 18350 so low in capacity?

Hello children!

I am switching from 16340 to 18350 and one thing I noticed: The cells are mainly under 1000mah and the highest available is only 1100mAh.

If you look at 18650 – 3600mAh is nowadays possible, 3400mAh not rare at all – 3000mAh for High-Current ones.

18350s are roughly half the size of a 18650 – so why is the capacity less than a third?

Edited by: L4M4 on 08/09/2017 - 15:25
HKJ's picture
Last seen: 6 hours 22 min ago
Joined: 05/24/2011 - 12:23
Posts: 5720
Location: Copenhagen, Denmark

Because they are using old technology. One manufacturer has updated to a more modern technology (Aspire), but not as good as the big manufacturer.

You can find test of Aspire here: http://lygte-info.dk/review/batteries2012/CommonSmallcomparator.php

My website with reviews of many chargers and batteries (More than 1000): http://lygte-info.dk/

djozz's picture
Last seen: 3 hours 34 min ago
Joined: 09/07/2012 - 17:04
Posts: 11601
Location: Amsterdam

Unlike the 18650 size, used in laptops, powertools, electric cars, the 18350 size is not used in any widespread application so no major effort is ever put into maximising their performance, even not as a spin-off from the 18650 achievements.

The only reason that we now finally have one decent performing 18350 cell (the Aspire) is the rapid spreading of e-cigarettes.

wle's picture
Last seen: 1 day 5 hours ago
Joined: 01/07/2015 - 13:49
Posts: 638
Location: atlanta ga

low volume, lack of interest

the same question could be posed of the 16340.

most 18350s have no more energy than a 16340, even though they are bigger – making the ‘most lame’ award to the 18350 for being bigger but no stronger


maukka's picture
Last seen: 5 hours 45 min ago
Joined: 12/31/2015 - 04:15
Posts: 966
Location: Finland
wle wrote:
most 18350s have no more energy than a 16340, even though they are bigger – making the ‘most lame’ award to the 18350 for being bigger but no stronger

On the other hand, there’s no real high discharge 16340s but at least one good 18350.

Newlumen's picture
Last seen: 3 sec ago
Joined: 05/27/2017 - 00:19
Posts: 419
Location: United states

Try windyfire IMR 18350! This battery might be low in capacity and it can handle higher amp and 3000- 4000 lumen in the flashlight..

rizky_p's picture
Last seen: 13 hours 2 min ago
Joined: 03/01/2011 - 05:06
Posts: 831
Location: Indonesia

basically no big commercial uses so no effort in putting newer tech, actually 26650 is in similar situation the capacity is rather low compared to its volume, a single 26650 using energy density of top tier 18650 could at least reach 7000mah based on volume even 20700 could reach 4500mah.

Ronin42's picture
Last seen: 3 days 3 hours ago
Joined: 12/17/2014 - 22:17
Posts: 1669
Location: Alameda, CA

I think we are all saying the same thing.

18350 is about half a 2200 18650

(“It’s good that most people can’t remember their previous lives. Otherwise
things would be a lot more complicated than they already are.”
Ajaan Lee Dhammadharo)

DBSAR's picture
Last seen: 53 min 55 sec ago
Joined: 02/11/2013 - 23:28
Posts: 4536
Location: Ontario, Canada

The same goes for 32650 as it does for 26650 & 18350 cells. Lack of demand for higher densities and capacities lie the more popular 18650 format. ( can include current available 14500 formats in this case too) Based on volume, a top-capacity built 32650 can probably be built to even reach 10 Ah or 11 Ah (based on the weight and volume of a 3600 mAh 18650. and as mentioned by rizky a 26650 should reach 7 Ah +, and if the same were applied to a 18350 then at least 1500 to 1600 mAh should be attainable.

That Canadian flashlight guy & Lantern Guru -Den / DBSARlight

Lexel's picture
Last seen: 9 hours 18 min ago
Joined: 11/01/2016 - 08:00
Posts: 3715
Location: Germany

if the battery gets shorter there is always about 7mm of the cell that can not be used for the active foil of the battery
so if you calculate it there should be almost 50% of the capacity possible

so from 65mm of a 18650 then 58mm are useable for capacity
and from 35mm of a 18350 then 28mm are useable for capacity

28/58 = almost 48.3%