laptop battery and charger voltage

[Faisal Nouman]

Hello all
i want to ask a question and having some confusion
i have a dell inspiron series laptop with battery rated voltage 11.5v
while the charger is rated at 19 volts. So what is actual laptop operated voltage ???
when we connect charger alone is it operate on 19 volts ?? and when we operate on battery, laptop operates on 11.5v ??
why there is such difference in voltage ??
please help me
Thanks in advance

 

[tpetar]

Voltage of battery will fall with usage. Inside laptop there is voltage stabilisation parts which provide safe and constant voltage level for device parts.

For now we dont have ideal battery with constant voltage during charging/discharging process, but I'm pretty sure we will have some super-batteries inside every device.

 

[Faisal Nouman]

i want to know why there is so huge miss match in two voltages of battery and charger

 

[tpetar]

i want to know why there is so huge miss match in two voltages of battery and charger

Best way to understand that is to read about :

- Battery voltage ranges (empty/full/charging)

- Voltage stabilization (linear/switcher Vi-Vo difference requirements)

- Read about constant current chargers



Li-Ion Charging Example :

3,7V x 4 cells in serie = 14,8V
Single cell charge to 4,2V. 4 x 4,2V = 16,8V + Voltage drop of psu under load and other control circuit Vi-Vo voltage needs.

In some other hands, manufacturers probably look to made one psu which cover more laptops models, with voltage and current, whether or not laptop battery contain more or less cells. Its easier to make lower voltage from higher, than vice versa.



Charging Lithium-ion