Building a solar panel charger that is functional with several battery types is discussed in this article.
By modifying a tiny component of the circuits zener diode which can power batteries with voltages of 12V, 24V, or even 48V.
As a result it can be used for a wide range of purposes
What is a High Current Solar Battery Charger Circuit for 12V, 24V, 48V Batteries:
A circuit for a high current solar battery charger is made to effectively use solar panels to charge batteries.
In order to safely charge larger batteries such as 12V, 24V or 48V batteries which are often used in solar power systems due to which circuit must be able to handle higher currents.
To control the charging process and safeguard the batteries against deep draining or overcharging this design generally includes a solar charge controller.
How the Circuit Works:
Parts List:
| Category | Component | Quantity |
|---|---|---|
| Resistors | 100Ω 1W CFR | 1 |
| Semiconductors | Schottky Diode (STPST15H100SB) | 1 |
| Zener Diode 15V 1W | 1 | |
| Transistor TIP35 | 1 | |
| Heatsink | Heatsink for Schottky Diode | 1 |
| Heatsink for Transistor TIP35 | 1 | |
| Solar Panel 18V 10Amp | 1 |
An emitter follower setup is used with transistor TIP35.
The transistors base is connected to a zener diode in this configuration while the emitter is connected straight to the solar panels positive terminal.
A voltage reference is provided by the zener diode.
Since a 15V zener diode is used in this high current solar battery charger circuit the transistors base voltage is set at about 15V.
This causes the transistors output voltage to be set to about 14V for a 12V battery.
The diode stops reverse current flow and ensures that current only moves from the solar panel to the battery.
The solar panel has an 18V/10A rating.
To charge the battery the transistor controls this voltage to a suitable level.
Its ability to charge batteries at different voltages i.e 12V, 24V, and 48V is what gives this circuit its versatility.
This can be achieved by adjusting the value of the zener diode.
Thus a 30V zener diode should be used with a 24V battery and a 60V zener diode when using a 48V battery.
The circuit serves as a voltage regulator keeping the output voltage for battery charging somewhat stable.
It is crucial to keep in mind that this is a basic design and that other features such as temperature adjustment, overcharge prevention and suitable voltage/current limitations are necessary for the best possible battery charging and its safety.
It is advised to carefully inspect, test and think about safety precautions to protect the batteries and the circuit before putting such a circuit into use.
Also one must be caution because lead acid batteries can be dangerous particularly when charged incorrectly.
How to Match Solar Panel with Battery:
Be aware of the batteries voltage V and ampere hour Ah rating before charging it.
Verify that the output voltage of the solar panel and the required battery voltage are equal.
Normally the voltage of the solar panel should be used near the battery voltage but not much higher.
For example lead acid and lithium-ion batteries have different charging characteristics.
To prevent damage make sure the battery chemistry and the solar panel voltage are matched.
The depth of discharge and desired charge rate are two examples of variables that may affect the charging time.
Select a charging time that works as per ones needs.
A solar panel with a current rating that matches or exceeds the estimated necessary current should be selected.
By doing this the battery will be charged effectively.
To control the charging process use a solar charge controller.
In addition to preventing overcharging charge controllers offer extra features for the best possible battery care.
Think about the area and climate in which the solar panel will be installed.
Factors including temperature, sunshine availability and shade can affect how well a battery charges.
The temperature factor has an effect on solar panel performance.
Make sure the panel you selected performs well in the planned temperature range.
Check that the connectors on the battery and the solar panel are compatible with one another.
Verify that the charge controller and other related parts can handle the total voltage system.
Example:
Let say one have a 12V 100Ah lead acid battery and want to charge it in 5 hours.
Required Current = 100Ah / 5 hours = 20A
You would choose a solar panel with a current rating of 20A or higher.
Formulas and Calculations:
Below mentioned formulas shows how much current (in Amps) needs to supply to charge a battery completely in a specific amount of time.
Required Current (A) = Battery Capacity (Ah) / Charging Time (hours)
Required Current (A): The electrical current required to charge the battery is represented by Amps (A) used to measure it.
Battery Capacity (Ah): This is the entire quantity of electrical energy that a battery is capable of holding.
Amp hours are used to measure (Ah).
Consider it to be the same size as an electrical container.
A greater capacity to hold more charge is indicated by a higher Ah rating.
Charging Time (hours): This is how long it takes for the battery to charge completely.
Hours (h) are used to measure it.
How to use the formula:
Find the Battery Capacity: Check your battery for the Ah rating.
The battery itself usually has this printed on it.
An average smartphone battery for example have a 3000mAh (milliAmp hour) capacity.
Divide this figure by 1000 to convert it to amp hours (Ah) as 1mAh equals 0.001Ah.
Because of this 3000mAh / 1000 = 3Ah.
Decide on Charging Time: Consider how long you would like the battery to charge.
Your demands and your chargers capacity will depend on this.
Calculate Required Current: Enter the desired charging time (hours) and battery capacity (Ah) into the formula.
For example if your 3Ah battery needs to be charged in 2 hours:
Required Current (A) = 3Ah / 2 hours = 1.5A
This shows that in order to fully charge your battery in two hours one need a charger that can deliver at least 1.5 amps of electricity.
Note:
In addition to be to simple this calculation ignores charging issues.
The real charging times can be a little bit longer.
When it comes to charging your particular battery always follow the manufacturers instructions.
Certain batteries could have restrictions or requirements when it comes to charging.
How to Build:
Follow the below mentioned steps for building a High Current Solar Battery Charger Circuit for 12V, 24V, 48V Batteries:
- Identify the collector, base and emitter pins of the TIP35 transistor.
- Connect the collector to the positive terminal of the solar panel through a 15A diode cathode of the diode facing the solar panel.
- Connect the emitter directly to the positive terminal of the battery.
- Connect the anode of the zener diode to the base of the TIP35 transistor.
- Connect the cathode of the zener diode to the ground or negative side of the circuit.
- Connect the negative terminal of the solar panel to the negative terminal of the battery.
- The TIP35 transistor may generate some heat.
- Ensure that it is mounted on a heat sink or in a way that allows proper heat dissipation.
- Connect the solar panel to the circuit and monitor the voltage across the battery terminals.
- Ensure that the voltage is within the safe charging range for the specific battery type.
- Implement safety measures such as fuses or circuit breakers to protect against overcurrent.
- Monitor the charging process and ensure that the battery does not overcharge.
- Depending on requirements one may need additional components such as resistors or capacitors for filtering or stability.
Notes and Considerations:
- To avoid overcharging make sure the voltages from the solar panel and Zener diode are suitable for the type of battery used.
- Before using the circuit to charge expensive batteries test it in a controlled atmosphere.
- For advanced battery charging management and protection features think about including a charge controller.
Safety:
- Keep in mind that creating this circuit for a high current solar battery charger requires a certain level of skill therefore if you are not familiar with electronics one should get help from an experienced person or speak with an expert before trying to construct this circuit.
- To prevent mishaps or damage follow the safety rules and regulations as well.
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