Battery Adc Measuring

Thread Starter

EYT1

Joined Apr 7, 2020
84
hi,
How can I measure the healthiest one by one while the 2 connected batteries are in charge state?

voltage divider did not give correct results.


pil.JPG
 

Papabravo

Joined Feb 24, 2006
13,743
What voltage divider. I don't see a voltage divider. I see two batteries and a PIC microcontroller with it's reset line pulled up. At least I think you mean for it to be pulled up. Since there is no voltage divider, I'm tempted to ask why "it did not give correct results". Your statement contains no verifiable factual information. Am I missing something?
 

Thread Starter

EYT1

Joined Apr 7, 2020
84
What voltage divider. I don't see a voltage divider. I see two batteries and a PIC microcontroller with it's reset line pulled up. At least I think you mean for it to be pulled up. Since there is no voltage divider, I'm tempted to ask why "it did not give correct results". Your statement contains no verifiable factual information. Am I missing something?
I tried it with voltage divider, adc does not reflect the actual values when the battery starts charging. It only measures accurately when not charged
 

Papabravo

Joined Feb 24, 2006
13,743
I tried it with voltage divider, adc does not reflect the actual values when the battery starts charging. It only measures accurately when not charged
We don't know what your voltage divider looked like, and we don't know how your charger was connected. What voltages did you expect to find on the two batteries while they were connected to the charger? There are all kinds of possible mistakes you could have made but we will never know what they were or be able to help you if you keep the information to yourself.
 

Thread Starter

EYT1

Joined Apr 7, 2020
84
We don't know what your voltage divider looked like, and we don't know how your charger was connected. What voltages did you expect to find on the two batteries while they were connected to the charger? There are all kinds of possible mistakes you could have made but we will never know what they were or be able to help you if you keep the information to yourself.
pil.JPG
 

Papabravo

Joined Feb 24, 2006
13,743
Why is there no Ground symbolanywhere on this drawing?
Where is the processor's Vcc pin?
Why are you using the comparator input instead of the A/D inputs?

You must include complete information on a drawing when you are having trouble. You still don't understand what it takes to troubleshoot a problem by remote control. Let's give it one more try.
You might want to show us the code in the processor as well.
 

JohnInTX

Joined Jun 26, 2012
4,085
AN2 and AN3 could be configured as ADC inputs using Vdd as Vref.. if the 16F628A had an ADC module.. which it doesn’t.
 

JohnInTX

Joined Jun 26, 2012
4,085
Indeed. So it would help if @EYT1 :

Told us what PIC he’s using.
Posted the code.
Showed an accurate schematic.
Reported the voltages at the pins when the charger is off and on.
 

Picbuster

Joined Dec 2, 2013
998
hi,
How can I measure the healthiest one by one while the 2 connected batteries are in charge state?

voltage divider did not give correct results.


View attachment 207548
You have to be aware of the following;
Charging a cell or a series of cells will produce a voltage at the cell connectors not at the cell itself.
An internal resistor is in between. The charger voltage is measured.
When charge current is limited the voltage may drop.

Discharge is the same but the cell remains his voltage and the output will go low during this process.
The internal resistor is debit.

Which cell is better when two cells are in serial?
Is this simple equation acceptable ;
avg = (cell A+ cell B)/2

At full load!
If a cell < avg
1% , 10% or 25% lower.
In my opinion: when < 10% it should be replaced.

Picbuster
 
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