# RLC Circuit

Discussion in 'General Electronics Chat' started by jmahabir, Jun 5, 2013.

1. ### jmahabir Thread Starter New Member

May 16, 2013
3
0
Hello,
I would like to model the recharge characteristics for a single cell 4.2v @ 226mAH Li-poly battery, charge rate of 1C for simulation purposes.

I am having trouble determining the values for the capacitor and inductor. Would someone be able to provide some assistance with the transient formulas needed to determine the appropriate inductor and capacitor values needed?

Many Thanks,
Jonathan

2. ### crutschow Expert

Mar 14, 2008
13,497
3,373
L and C for what, the battery? Those are usually so small they can be neglected.

3. ### jmahabir Thread Starter New Member

May 16, 2013
3
0
Yes, I was hoping to use an inductor and capacitor to model the charge characteristics for the Li-poly battery.

I am working on the battery charger circuit in LT-spice however there is no rechargeable battery model in the library. If I am able to model the battery using passive components such as a resistor, and inductor to store the current a capacitor to store the voltage, I can confirm that the circuit is functioning correctly by terminating the charge when the battery reaches full capacity.

I will also be able to look at the current and the voltage plot with respect to time, the transient response, which I will also consider to be the charge curves for the battery.

Can it work in the way I am thinking of it or is there something else I can use to simulate as a single cell Li-poly battery?

4. ### #12 Expert

Nov 30, 2010
16,686
7,327
I think I see a problem. The idea that you can store energy in a magnetic field (inductor) is feasible but that amount of inductance has nothing to do with the real inductance (equivalent series inductance) of a battery. Besides, energy is only stored in a magnetic field when current is moving. You would have to use a superconductor to keep a magnetic field storing energy for even a few seconds. Similar with capacitance. You can store energy in a capacitor, but that amount of capacitance has nothing to do with the actual capacitance of a battery, and I'm sure you already see that as soon as you use up any of the energy, the voltage on the capacitor drops. What you're trying to do it like simulating a horse with a bale of hay. A battery and a horse convert chemical (potential) energy into a kinetic form of energy. I believe this is a "fail" right from the start.

5. ### jmahabir Thread Starter New Member

May 16, 2013
3
0
Thanks for taking the time to put things into perspective sir.

Best Regards.