Minimize charging time of a battery

[quuker]

the source is 120V DC with an internal resistance of 40 Ohms. the battery's emf is 10V with an internal resistance of 1kOhms. what can i add to the circuit to improve the charging time?

 

[Phrak]

Different batteries types have different charging requirements. What type are you recharging, and what is it, and from what level of discharge is it being charged from?

 

[quuker]

it's an lithium ion battery.

 

[Phrak]

Lithium is very tricky to recharge. Rechargers on the market rely upon microcontrollers to quick charge, and then to top-off. Lithium batteries tend to be a fire hazard if charged too quickly or are overcharged. They sell little fire supressing bags to recharge them into keep you from burning down your house due to a mishap. They can explode in a very exothermic fireball.

1) I'm suspicous of the 1K Ohm internal resistance value you've given. It sounds way too high.

2) One wouldn't normally charge a ~10 volt battery with 120 volts. To trickle charge you would use some supply, nominally greater than 10 volts, and include a limiting resistor, and cut-off voltage control for lithium.

3) Lithium ion cells output 3.6-3.7 volts. Where does the 10 volts come from?

4) Where do you get 120 volts DC? Rectification of the 120 VAC line gives you 168 volts.

5) Why don't you purchase a charger that won't burn down your mother's house?