High Current Solar Battery Charger Circuit for 12V, 24V, 48V Batteries

This article for High Current Solar Battery Charger Circuit for 12V, 24V, 48V Batteries talk about how to make solar panel charger that work with many battery types.

Just by changing small part in circuit the Zener diode can charge battery of 12V, 24V, even 48V.

So this charger are used for many different things.

What is a High Current Solar Battery Charger Circuit for 12V, 24V, 48V Batteries:

This circuit for high current solar battery charger is made to use solar panel good for charging battery.

To charge big battery like 12V, 24V or 48V which are used in solar system for that this circuit need to handle big current.

To control charging and protect battery from overcharging or too much draining this design usually have solar charge controller.

How the Circuit Works:

Parts List:

Here emitter follower setup used with TIP35 transistor.

Transistor base connect to Zener diode and emitter connects direct to solar panels positive wire.

Zener diode gives fixed voltage reference.

In this charger 15V Zener is used so transistor base get 15V.

Because of that output voltage become around 14V which is good for charging 12V battery.

One diode used to stop reverse current so current only connects from solar panel to battery.

Solar panel is rated 18V 10A.

Transistor control this voltage which make it good for charging battery.

This circuit can charge different battery voltages like 12V, 24V and 48V which just need to change Zener diode value.

For 24V battery use 30V Zener and for 48V battery use 60V Zener.

This circuit work like voltage regulator which keeps voltage stable for battery charging.

But this is basic design and it does not have features like temperature control, overcharge protection or current limits.

Before using this circuit better to test and check the safety.

Keep in mind battery and circuit both need protection.

Also we must be careful with lead acid battery which can be dangerous if charged wrong way.

How to Match Battery with Solar Panel:

Before charging first know battery voltage (V) and ampere hour (Ah) value.

Be sure solar panel voltage is same or close to battery voltage and is not too much higher.

Different batteries like lithium-ion and lead-acid charge in different ways.

So solar panel voltage must match battery type to avoid damage.

Charging time depends on how empty battery is like the depth of discharge and how fast we want charge like charge rate.

Choose charge time as per our need.

Better to use solar panel with current rating same or more than what battery needs and this helps battery charge properly.

Always use solar charge controller which protects battery from overcharge and helps keep battery in good condition.

Check place where solar panel are used like sunlight, shade and temperature matter.

Less sun or too much heat can affect the charging.

Be sure panel works well in the temperature where it will be placed.

Also check all parts like solar panel, battery and charge controller which can work together but the connections should match.

Charge controller and other parts must handle full system voltage safely.

Example:

Lets say someone have 12V 100Ah lead-acid battery and want to charge it in 5 hours.

So Required Current = 100Ah ÷ 5 hours = 20A

That means one should choose solar panel that can give 20A or more current.

This way battery can charge properly in 5 hours.

Formulas and Calculations:

Formula to Find How Much Current Needed to Charge Battery:

To know how much current (in Amps) are needed to charge battery fully in certain time then we can use this formula:

Required Current (A) = Battery Capacity (Ah) ÷ Charging Time (hours)

What the Terms Mean:

Required Current (A):

This mean how much electric current (Amps) is needed to charge battery.

Battery Capacity (Ah):

This shows how much energy battery can hold.

It is written in Amp hours (Ah).

Think like battery is a container and more Ah means bigger container so it can store more charge.

Charging Time (hours):

This is how many hours it will take to charge the battery full.

How to use the Formula:

Find Battery Capacity:

Look at the battery find the Ah value printed on it.

Example: A phone battery may say 3000mAh (milliamp hours).

Convert to Ah:

3000mAh ÷ 1000 = 3Ah

Decide Charging Time:

Think how many hours we want battery to charge.

This depends on our need and charger power.

Use Formula to Find Current:

Put values into formula.

Example:

If 3Ah battery must charge in 2 hours:

Required Current = 3Ah ÷ 2 hours = 1.5A

So we need charger that can give at least 1.5A.

How to Build:

Follow the below easy steps to build High Current Solar Battery Charger Circuit for 12V, 24V or 48V Battery:

• Check which pin is emitter, base and collector on TIP35 transistor.
• Use 15A diode and connect cathode (line side) of diode to solar panels positive terminal.
• Then connect collector of TIP35 to the anode (other side) of diode.
• Connect emitter of TIP35 direct to battery positive terminal.
• Connect anode of Zener diode to base of TIP35.
• Connect cathode of Zener diode to ground (negative side) of the circuit.
• Connect Solar Panel Negative to Battery Negative:
• Join solar panel negative wire to battery negative terminal.
• TIP35 gets hot so fix it on a heat sink or metal surface to cool it down.
• After connecting check voltage at battery terminals.
• Be sure it is safe and okay for that battery type like 14V for 12V battery
• Add fuse or circuit breaker to protect from overcurrent.
• Keep eye on battery while charging and do not let it overcharge.

Safety Tips:

This circuit needs basic electronics skills.

If anyone is not sure about electronics get help from someone with experience or talk to an expert.

Always follow safety rules to avoid electric shock, battery damage or fire.

Conclusion:

This High Current Solar Battery Charger Circuit is useful for charging 12V, 24V and 48V batteries.

By changing the Zener diode it can work with different battery voltages.

It is simple but powerful design which is good for heat sink and safety parts like fuse which are important.

Always test carefully and follow safety.

References:

100 V – 15 A DPAK power Schottky trench rectifier

SOLAR BATTERY CHARGER