Thinking of a battery like a water reservoir for your device.
This clever circuit acts like a watchful caretaker.
It keeps an eye on the battery level and automatically gives it a little top up whenever it starts to run low.
This ensures the battery is always full and ready to go perfect for things like backup power systems, solar lights or your favorite wireless toys.
Circuit Working:
Parts List:
This battery charger is designed to maintain a battery at a nearly full charge.
It is composed of 7 components and is used with a 12V to 18V DC plug pack.
The plug pack should provide more than 15V when not connected to a load which is typical for most 12V plug packs.
Suitable for batteries ranging from a 1.2AH gel cell to a 45Ahr car or boat battery this charger can be left connected for extended periods without the battery losing water due to gassing.
It maintains an output voltage of 13.2V just enough to prevent the battery from discharging.
However, charging a flat battery will take a considerable amount of time since a batteries floating charge is around 13.6V when being charged at a reasonable current whereas this charger is designed to deliver only a small current.
There is a slight distinction between an old fashioned car battery often referred to as an accumulator and a sealed battery like a “gel cell”.
A Gel Cells plate composition prevents gassing until a high voltage is reached.
This allows it to be completely sealed with only rubber bungs that release gas at high pressure if grossly overcharged.
Therefore, the charging voltage must not exceed certain limits and once the battery is fully charged the charging current should drop to a very low level.
Formulas and Calculations:
The below mentioned formula is for calculating the output voltage:
Vout = 12 + (0.6 * total numbers of diodes)
= 12 + (3 * 0.6)
=13.8V
here,
- Vout output voltage of the circuit
- 12 is the fixed output voltage of IC 7812
- 0.6 is the voltage drop across each diode
How to Build:
To build a Simple Circuit to keep a Battery Topped Up following are the steps for assembling:
- Connect IC 7812 input pin to +15V DC charging input.
- Connect the ground pin of the IC 7812 to ground line through 3 series connected 1N4004 diodes.
- Connect the out pin of the IC 7812 to the positive terminal of battery through a diode 1N4004, 2nos 10 ohm resistors, all connected in series.
- Connect the negative terminal of battery to the ground line of the charging input supply.
Note:
- Remember to take all necessary safety precautions when working with electricity.
Conclusion:
A simple circuit to keep a battery topped up is an effective and efficient way to maintain a rechargeable battery at its full capacity.
By using components such as a voltage regulator, resistors and a diode, this circuit ensures that the battery receives a steady and controlled charging voltage extending its lifespan and ensuring optimal performance.
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