The charger adjusts it output to obtain the correct charging current.
Hi, assuming constant current 2A, so the voltage to charge the battery is 2A*0.28Ohms=0.6V ? The charging voltage must be higher than battery. Seems confusing. Or is it current voltage of battery+0.6V to charge?The charger adjusts it output to obtain the correct charging current.
Because, if you connect the battery to a load of 2.5ohms, the battery would appear to be 2.5v.View attachment 254171
Lithium ion cell are charged at 5V and 2A max. Following Ohm's Law, 5V/2A would mean at least a 2.5 Ohm internal resistance of battery.
However, Lithium ion internal resistance is only about 0.28 Ohms. How is that possible ?
There are buck/boost "lids" on some newer lithium packs and single cells that allows them to be charge by simple USB chargers and discharged as 5v usb supplies. I think he does not have a raw Lithium battery.A Lithium-Ion cell has a maximum do not exceed charging voltage of 4.20V. It will explode and catch on fire if your charging circuit gives 5.0V and does not limit the charging voltage to 4.20V.
A lithium-Ion cell will also explode and catch on fire if your charger circuit does not limit the charging current.
Maybe the power supply to the charging circuit produces 5V at 2A? Many cell phones have the charger circuit inside the phone and uses a 5V at 2A power supply.
Maybe the battery has a protection circuit inside it that limits the voltage and current?
I agree but the question was about internal resistance of a power source, not the semantics discussion over "of what is a battery". Most people (like many new members on this site) call any chemically stored energy a "battery".Then it is called a "power bank" not a lithium battery.
I have a power bank with a USB 5V at 2.1A input and it has a voltage boosted output of 5V at 2.1A output. Its rating is 16Ah.
The power bank has a charger circuit for its Lithium battery and a voltage boosting circuit for its output.
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