Author Topic: Li - Ion Smart / Battery Charger  (Read 1514 times)

0 Members and 1 Guest are viewing this topic.

Offline StreetRoosterTopic starter

  • Newbie
  • Posts: 7
  • Country: za
Li - Ion Smart / Battery Charger
« on: March 22, 2019, 10:27:11 am »
Hi Everyone

I have a number of 3.7V 6600mAH Li batteries, and am asking if anyone has a circuit for a smart charger for my batteries.
 

Offline aldi

  • Contributor
  • Posts: 28
  • Country: nl
Re: Li - Ion Smart / Battery Charger
« Reply #1 on: March 22, 2019, 05:34:53 pm »
We need more specifications, such as:
Input voltage, charge current, interface (I2C or just pins?). Any need for protection? And what do you mean with "smart"?
 
The following users thanked this post: StreetRooster

Offline Gandalf_Sr

  • Super Contributor
  • ***
  • Posts: 1729
  • Country: us
Re: Li - Ion Smart / Battery Charger
« Reply #2 on: March 22, 2019, 05:38:50 pm »
I've done several designs, it's best to use an IC dedicated to charging Lithium batteries, Texas Instruments have several.  What is the maximum charge current?
If at first you don't succeed, get a bigger hammer
 
The following users thanked this post: StreetRooster

Offline StreetRoosterTopic starter

  • Newbie
  • Posts: 7
  • Country: za
Re: Li - Ion Smart / Battery Charger
« Reply #3 on: March 25, 2019, 09:06:02 am »
Thank you or replying to my post.

What I mean by " Smart " is that when I start charging the battery the charger will be able to detect the battery's Voltage.
In my case these are 3.7V
It will then start charging in CC mode, in my case that will be 3A as these batteries are 6000mAH.
When the 3.7V is reached the charger then reverts to CV mode.
It will remain in this mode until a residual charging current of +- 150mA is reached and then switch off.
 :-//
 

Offline Daixiwen

  • Frequent Contributor
  • **
  • Posts: 367
  • Country: no
Re: Li - Ion Smart / Battery Charger
« Reply #4 on: March 25, 2019, 09:47:30 am »
What you describe is what most dedicated Li-Ion charging chips do. Just pick your manufacturer and any reference that can charge 1S batteries (meaning one element, and not several in series).
Double check your voltage though. 3.7V is most probably your cell nominal voltage, but its charging voltage is more likely 4.2V. If you charge it only to 3.7V you'll only get about half its capacity.
 

Offline StreetRoosterTopic starter

  • Newbie
  • Posts: 7
  • Country: za
Re: Li - Ion Smart / Battery Charger
« Reply #5 on: March 25, 2019, 09:58:33 am »
Thank you
Maximum charge current will be 3A.
Battery Voltage 3.7V
 

Offline StreetRoosterTopic starter

  • Newbie
  • Posts: 7
  • Country: za
Re: Li - Ion Smart / Battery Charger
« Reply #6 on: March 25, 2019, 10:00:53 am »
 :-+ I follow, the 3.7 V is whats printed on the battery.
 

Offline KL27x

  • Super Contributor
  • ***
  • Posts: 4108
  • Country: us
Re: Li - Ion Smart / Battery Charger
« Reply #7 on: March 26, 2019, 02:42:17 am »
3.7V is printed on the battery because that's the nominal output voltage under load. The charge/float voltage would be 4.2V. Daixiwen was generously allowing for the possibility that you live in an alternate universe.
 
 

Offline AlienRelics

  • Supporter
  • ****
  • Posts: 74
  • Country: us
    • AE7HD
Re: Li - Ion Smart / Battery Charger
« Reply #8 on: March 26, 2019, 06:48:21 pm »
Which chemistry? Most have a terminal charge voltage of 4.20V, but not all.

https://batteryuniversity.com/learn/article/types_of_lithium_ion

Way more information on Lithium Ion cell charging:
https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

It really is a wise idea to select a chip dedicated and designed for Lithium Ion charging.
Steven J Greenfield AE7HD
 

Offline KL27x

  • Super Contributor
  • ***
  • Posts: 4108
  • Country: us
Re: Li - Ion Smart / Battery Charger
« Reply #9 on: March 27, 2019, 08:06:21 am »
In an alternate universe, those other chemistries might be relevant. That info is 20 years old* when those cells still showed (or at least more recently had shown) potential. One of those...(LiFeO4 ? Something like that) is still alive and used in some applications like EV's. But if the cells are marked 3.7V, you know exactly what it is. It's the one that is 99.9% of the li ion battery industry.

*I not only read about these chemistries nearly 20 years ago, I read it from this exact site. This site has not changed much in the interim.
« Last Edit: March 27, 2019, 08:32:36 am by KL27x »
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf