Getting battery level, while in charge

[perfaram]

Hi all !
First thing, you must know that I'm a total newbie about electronics (but not about programming).
So here's my question : Is it possible, using this Li-Ion battery charger and this battery current sensor to get the battery charge level ?
Seeing how the current sensor works and is designed, I think it that, when charging, it will show an unrealistic percentage. But i'd like to be proven wrong !
Here's what I've been thinking to :

BATTERY-SENSOR.png (154 KiB) Viewed 374 times

Any ideas ?

[adafruit_support_bill]

No. As diagrammed, it would just short out the battery. But it would not work anyway. Since it is a current meter, it will only tell you what the charge current is. That actually decreases in the last phase of the charge.

What will work to some degree is a voltage meter. The battery voltage will range from about 3v when drained to about 4.2v when fully charged. It is not completely linear over the charge cycle, but it will give you an idea of when you are approaching full charge.

[perfaram]

Since it is a current meter, it will only tell you what the charge current is.

Exactly what I expected...

measure both the high side voltage and DC current draw

So, can I use INA219 as a voltage meter ? Or should I use another thing ? Is there any voltage meter that is known to be good ?

Thx in advance

[adafruit_support_bill]

An Arduino analog pin will read 0-5v with 10-bit resolution. You can use an ADS1115 if you want 15-bit resolution.

[perfaram]

Here's what I came to :

board_bb.png (126.25 KiB) Viewed 329 times

But again, I think I will just get the charge voltage...

[adafruit_support_bill]

Don't connect the Arduino 5v pin to the output of the charger! That will put 5v directly across the battery terminals.

How are you powering the charger?

[perfaram]

I'm just reproducing what I saw here

If you want to use the battery while also having it connected to the charger (less plugging and unplugging that way) you can simply use the BATTERY OUT connecion on the right. The IN and OUT ports are connected together on the circuit board so it acts as a pass-through

To charge, connect a power supply to the top of the board.

The charger is powered using USB. And the battery shown in the schematic is a placeholder.

[perfaram]

Sorry, just understood what you meant... yes, I screwed the schematic. Battery + must be connected to VIN...