/diy/ - Do It Yourself

[Anonymous No.1621326]

How do I calculate the time needed to charge a Li-on (4.2V) (eg. 2000mAh) battery using constant current and constant voltage (CCCV) with a lab power supply taking into account the initial battery voltage (assuming the battery is only partially discharged)?

[Anonymous No.1621329]

>>1621326
>using constant current and constant voltage (CCCV)

read a book then come back and rephrase your question.

[Anonymous No.1621331]

>>1621326


>>>/g/71215670

lol

[Beppí No.1621332]

>>1621326
I wonder if this translates. Read up on Battery U and come back. Or just run the CC/CV charge and see how long it takes because cells have all different capacities based on temp and age and cycles and all other variables. You really should just be focusing on the time it’s at CV.

[Anonymous No.1621342]

>>1621332
So what do if there is no way to tell the remaining capacity? I have a few dozens of batteries from various producers and different models, part of them are not even labeled. Any other way then to use a microprocesor charger?

[Beppí No.1621350]

>>1621342
Do you know how CC/CV works? Read up on it. As long as you know they’re supposed to be 4.2V fully charged, just run 500mA- 1A CC to be safe up to 4.2V, then it switches to CV at 4.2V and the current will start dropping. So total time depends on the cell and all those variables, but to make it easy, just start the timer when you hit 4.2 and it switches from CC to CV, and time it for an hour or two after that or watch for the current to drop off real low.

Try to find the data sheets of known cells and read up on C ratings because that will tell you everything about the optimal current to charge at.

[Beppí No.1621351]

>>1621342
>>1621350
This is a good website

https://batteryuniversity.com/index.php/learn/article/charging_lithium_ion_batteries

[Anonymous No.1621360]

>>1621350
Right, so I did misunderstood the CC/CV algorithm. I have a power supply with regulated voltage and amperage. I'd have to raise the voltage over time by hand so it appears it's not really possible for me to charge the batteries using CC/CV.

[*]

[Beppí No.1621371]

>>1621360
You might be able to use that supply, but I’m not smart enough with electrocity.

There are tons of cheap 18650 chargers, some of them that hold 2 cells or 4 cells and have little displays with voltage and current for $10-$20. Otherwise you could get pic related if you wanna play around, it has CC/CV so feed a power supply into it (either the one in your pic or some DC laptop supply or whatever) and then you can follow the instructions on how to charge Li Ions.

[Anonymous No.1621382]

>>1621371
The power supply is fine but I'd have to mod it to handle the charging with an arduino. The voltage and current are controlled by potentiometers so it should be easy to replace them with arduino analogue pins.

[Anonymous No.1621568]

This might help, or it might not.
https://lygte-info.dk/

[Anonymous No.1621596]

>>1621360
>I have a power supply with regulated voltage and amperage. I'd have to raise the voltage over time by hand
You set the voltage limit at the target voltage
You set the current limit at the current you want to charge at.
The battery is below target voltage so current limited
When it hits voltage limit the psu will drop the current to keep voltage limit.
That's how every limited psu works.
Don't say amperage when you mean current unless you are a brainlet.

[Anonymous No.1621621]

What is the C rating of the battery? This will tell you the rate at which it can charge and discharge safely.. Also remember that you can either have a constant voltage at a varying current or have a constant current with varying voltage not both.

In any case as a general rule charging it at twice the amp hours should not be an issue

[Anonymous No.1623163]

>>1621326
drain it fully
press th e stop watch app on your phone
charge it up
look at the time