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#### vidhz

##### Newbie level 5
Hii...

Please help me to make simulink/matlab model of 12V 4.5Ah lead acid equivalent circuit. I also need to know how to design its resistance an capacitance values. Also help me with the charging and discharging control of equivalent circuit.

Thank you

What sort of help do you need?

What is your design thus far?

Hii..

Actually I need to know the parameters of the equivalent circuit and its design.. then I need to know how to control its charging process...everything required to make a SIMULNIK model

Thank You

A capacitor is a simple way to model a battery. Say 1000 F. The time step might need to be increased to suit.

Since a battery has internal resistance, put a few tenths of an ohm inline.

Since a battery will self-discharge, put a resistor across the capacitor (say 470 ohms).

When we compare charging curves, the capacitor volt level rises on a curve similar to charging a battery.
However when starting out fully charged, the capacitor volt level drops much more steeply compared to the battery.

When discharging a fully charged cap, its ampere flow resembles a battery.
However when charging, the capacitor ampere flow drops much more steeply than the battery.

There are anomalies which will take effort and ingenuity to remedy.

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Screenshot:

How about controlling the switches in the screen shot you have uploaded for charging and discharging process??

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Actually I am developing a Photovoltaic system. I have modelled a solar panel with maximum power point tracker in MATLAB/SIMULINK. The output of solar panel is connected to a battery. Battery output is connected to a buck boost converter which is again connected to a load. Everything is connected in series.

What I require is to make the equivalent circuit of the lead acid battery with R and C. Also I need to cut off the panel from the battery when battery is fully charged and reconnect when battery voltage goes below a particular value.

What I need to know is how to control the switch at the input side of battery so that battery is disconnected when fully charged and reconnected when battery voltage goes below a particular value. I tried applying this logic by comparing the battery voltage using a "compare to" block in SIMULINK. But it is not the correct method.

I hope I have made everything clear.

Thank you

How about controlling the switches in the screen shot you have uploaded for charging and discharging process??

The simulator is interactive and animated.

https://tinyurl.com/axe6d53

You can click on the switches to open and close them.

You can alter values at will. Right-click on a component and select Edit.

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What I require is to make the equivalent circuit of the lead acid battery with R and C. Also I need to cut off the panel from the battery when battery is fully charged and reconnect when battery voltage goes below a particular value.

What I need to know is how to control the switch at the input side of battery so that battery is disconnected when fully charged and reconnected when battery voltage goes below a particular value.

The thread below has my schematic for a simple charge controller. I constructed a hardware version of it for my solar panels and battery bank.