If a charger was using a simple full wave bridge rectifier design (such as: **broken link removed**). How could you modify it to have an LED indicator about the charge status of the battery? My original thinking was to run an LED in series with the load (rechargeable battery), but that was based on thinking that the battery would eventually stop taking a charge and no current would flow through that node anymore...so the LED would shut off. I've decided that probably wouldn't work though. Can someone help me with this?
The battery would be a Li-ion used in an iPod. I think we're supposed to assume that the battery wouldn't fry because of no voltage regulator and just show how an LED indicator could be implemented. If you just assumed things were regulated, how could you modify that circuit to include an LED indicator?
A lithium battery will catch on fire (a very hot fire, look in Google at videos) if it is incorrectly charged or discharged.
1) A circuit must sense the battery voltage to be more than 3.0V for ordinary charging. If the voltage is less than 3.0V then a low charging current is used.
2) The charging current must be regulated to the amount recommended by the battery manufacturer.
3) The voltage must be regulated within 1% of 4.2V. A current-sensing circuit must detect when the current has dropped to 3% of the regulated amount.
4) The current-sensing circuit must turn off the charger to prevent overcharging.
Use a battery charger IC made to charge a lithium battery.