Duration of a plain 18650 cell charge...

Externet

Well-Known Member

• May 8, 2021

• #1

Hi.
A common lithium cell, charged to 4.2V. If it is rated to 2000mAH, is it supposed to be capable of delivering 2 Amperes during 1 hour? Or 0.2 Amperes during 10 hours ?
Should a 30mA drain last for 2000/30 = 66 hours until reaches its depleted voltage, whatever it is ? Or is it only at a certain duty cycle per manufacturer specifications ?
What to expect at 100% on duty cycle, no off periods ?

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• May 9, 2021

• #2

You would need to test it and see what happens, 'usually' ratings are for fairly low discharge currents - but perhaps not so much for Li-Ion?.

A simple google finds plenty of data:

 

alec_t

Well-Known Member

Most Helpful Member

• May 9, 2021

• #3

Externet said:

If it is rated to 2000mAH

Click to expand...

You would need to read the datasheet to know under what conditions that rating applies. A dishonest rating might exaggerate the capacity by drawing a trivial current and running the battery down to a dangerously low voltage.

 

audioguru

Well-Known Member

Most Helpful Member

• May 9, 2021

• #4

2000mAh is low for a 18650 Li-Ion cell today (most are 3000mAh to 3600mAh) so maybe yours is old and its life is gone.

 

Externet

Well-Known Member

• May 9, 2021

• #5

Currently being sold. Do you want more ?

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• May 9, 2021

• #6

Externet said:

View attachment 131299View attachment 131300View attachment 131301View attachment 131302View attachment 131303View attachment 131304View attachment 131305View attachment 131306View attachment 131307View attachment 131308View attachment 131309View attachment 131311View attachment 131312View attachment 131314

Currently being sold. Do you want more ?

Click to expand...

The ones we buy are 2600maH Samsung ones, UK sourced from a wholesaler.

However, I've got some higher power ones at home I bought from Banggood - and while they work fine, are actually slightly larger than normal 18650's Presumably they get the higher power by been a bit bigger!.

 

audioguru

Well-Known Member

Most Helpful Member

• May 10, 2021

• #7

The attachments show many No-Name-Brand batteries probably made "over there" in somebody's basement and are sold to Vapers.
google shoes many articles and videos about fake or counterfeit 18650 battery cells mostly full of flour.
Who uses more 18650 battery cells, Vapers or Laptops?