Hi everybody. I am defintely what you can call a newbie regarding electronics Recently i got this li-ion battery charger circuit with 12 v input made by a questianable freelancer, and i do not have the skills to look for errors. The circuit looks like this:

Let me know, if I forgot information about the project.
Any feedback will be appreciated.

 

Welcome to AAC!

That circuit is completely inappropriate for any lithium battery chemistry. Those batteries could start fires if abused.

Why would you use a questionable design when you can buy something for not very much money?

Here's some reputable information regarding charging lithium batteries:
https://batteryuniversity.com/article/bu-409-charging-lithium-ion

 

hi ejn

What are the details of your Li-Ion battery.
E

 

A Li-Ion battery cell is 3.7V when it is sold because 3.7V is its half-charged storage voltage. It can stay at 3.7V for years in a store before it is sold. The max charged voltage is 4.20V.
Two cells in series are a max of 8.40V and are fully charged when the charging current has dropped to 1/20th the capacity.

To avoid an explosion and fire, use a Li-Ion battery charger IC instead.

 

made by a questianable freelancer

Questionable is right.
A proper Li-Ion charger cuts off the charge current when the battery is fully charged to prevent overcharging and possible catastrophic (i.e. fire and/or explosive) battery failure.
That circuit does not do that.

 

A Lithium battery charger circuit also senses cell voltage before charging. If the voltage is too low then the charger circuit attempts charging with a low current because if the cell is shorted with a fragment of metallic lithium the fragment will explode and catch on fire if fed a normal high charging current.

 

Welcome to AAC!

That circuit is completely inappropriate for any lithium battery chemistry. Those batteries could start fires if abused.

Why would you use a questionable design when you can buy something for not very much money?

Here's some reputable information regarding charging lithium batteries:
https://batteryuniversity.com/article/bu-409-charging-lithium-ion

That was what i was affraid of, when ordering such things cheaply from fiverr. Maybe looking into it myself is the best solution. Will be looking at the article you sent. Thank you very much

 

A Li-Ion battery cell is 3.7V when it is sold because 3.7V is its half-charged storage voltage. It can stay at 3.7V for years in a store before it is sold. The max charged voltage is 4.20V.
Two cells in series are a max of 8.40V and are fully charged when the charging current has dropped to 1/20th the capacity.

To avoid an explosion and fire, use a Li-Ion battery charger IC instead.

Any specific suggestions for such IC's?

 

hi ejn

What are the details of your Li-Ion battery.
E
View attachment 285709

I apologize for using the wrong channel.

This is the specifications for the batteries i am using:

14500 Battery Item specifics ：
Brand Name: GTF
Type: Li-Ion 14500
Nominal Capacity: 900mah（700-900mah）
Nominal Voltage: 3.7V
Weight: 19g±1g
Rechargeable Battery: Yes
Rechargeable Times: Up to 500 times
internal resistance: ≤60mΩ
Limited Charge Voltage: 4.2v
Working Voltage: 2.75-4.2V
Size: 14.1 mm x 49.7mm (Diameter)


Can i ask what software, you are using for that diagnostic?

 

That was what i was affraid of, when ordering such things cheaply from fiverr. Maybe looking into it myself is the best solution. Will be looking at the article you sent. Thank you very much

The circuit was ment to be produced and incoporated in some LED products i am currently working on. That is why i can't just buy them, and why it shouldn't have any flaws :-/

 

Any specific suggestions for such IC's?

Do you want to build your own circuit or just purchase a module?

 

Any specific suggestions for such IC's?

Modern Li-Ion or Li-PO battery charger IC are TP4056, LP2951 and LM3622.
Read about charging Lithium batteries at batteryuniversity.com .

 

A couple more are SY6912, MAX745
Those can handle multiple cells.

 

Do you want to build your own circuit or just purchase a module?

Build my own
.
It's gonna be a intergrated part of a bigger circuit. Therefore more convinent to make it myself

 

A couple more are SY6912, MAX745
Those can handle multiple cells.

But that shouldnt' be needed if multiple batteries are connected in parallel, right?

 

But that shouldnt' be needed if multiple batteries are connected in parallel, right?

Charging batteries in parallel, or series, is a compromise.

Check this article:
https://batteryuniversity.com/article/bu-302-series-and-parallel-battery-configurations

 

Build my own

I like the MAX1736.

 

But that shouldnt' be needed if multiple batteries are connected in parallel, right?

No, cells in parallel will just accept the charge they want at the applied voltage. EVs and home power banks can have dozens or hundreds of cells in parallel. Series might be a better choice in some applications; 3S is close enough to 12V to run most 12V devices, for example. In that case, use a "BMS" or "PCM" that provides protection from overcharging, over-discharging, short-circuits, and provides balancing. The buck converter chips ( SY6912, MAX745) that I mentioned provide the necessary voltage and current regulation for charging.

 

I really appreciate all the feedback and suggestions. Thank you all

 

I really appreciate all the feedback and suggestions. Thank you all

Have you decided on a solution?