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Can I charge a solar battery with a generator?

Sometimes solar energy is not that reliable. Seasons changes. During summer charging your solar batteries with sunlight is enough. However, for the sake of the cold seasons, you better have an alternative power source. Is there a way you can charge a solar battery using a generator? 

A generator is an effective power source that homeowners should have. In case of any inconveniences like a drained solar battery, you can use a generator to charge the battery. The process is quite simple. All you need is a small inverter and charging cables. Stick around to find out how you can go about charging your solar batteries with a generator.

Can I charge a solar battery with a generator?

Having an alternative power source in your home would save you during desperate times. Sometimes your battery might be too drained for the sun to charge it. The solar battery cannot charge properly during the winter. A generator can be of much help during these times. You will only need to learn how to connect the generator to your battery and then charging automatically starts. Knowing your battery specification will also help determine how you can control the charging process. 

A generator provides the required voltage used to charge the solar batteries. However, you cannot connect the solar battery directly. You will need an effective inverter to convert the AC power provided by the generator into DC that charges the battery. With the right equipment and a functioning generator, your battery will be reading fully charged. The guide below explains how you can successfully connect the solar battery to the generator. 

How do I charge my solar battery bank with a generator?

Step 1: Check the fluid level of both the solar battery and the generator

  • Ensure the fluid in both devices is enough. 
  • Add distilled water to the solar battery until you get to the marked line. 
  • Do not fill the fluid as it might spill.
  • As for the generator, check if the fuel available is enough to charge a battery. 

Step 2: Connect the inverter to the generator

An inverter will help regulate the current that reaches the solar battery. A high current might damage the battery permanently.  

  • Most generator inverters come with a plug-in cable.
  • Attack the inverter directly to the generator.

Step 3: Connect the charger to the solar battery

  • Ensure you can differentiate the negative and the positive of the battery. 
  • Clamp the charger to the battery terminals.
  • Do not touch the terminals.

Step 4: plug-in the charger to the inverter

  • After connecting the charger to the solar battery, you can then plug in the charger directly. 

Step 5: start the generator

The last step before your battery starts charging is starting the generator.

  • If it is an analog generator, start it by pulling the cord.
  • Alternatively Start the battery using the starter switch. 

Step 6: Leave the battery to charge. 

  • Before switching the battery charger, let the generator run for a few minutes. This is to allow the engine speed and voltage to stabilize.
  • Switch on the battery charger to start charging the battery. 
  • Let the battery charge till it’s full then reverse the process and disconnect the generator.

Charging a battery with a generator is risky. It should be done during emergencies 

only. You should follow these safety tips to avoid accidents. Keep checking the level 

of charge until it’s full then switch off the battery. If the solar battery has a solar battery maintainer, then it will automatically stop the charge from reaching the battery. So how long do you wait until the battery is fully charged?

How long does it take a generator to charge a solar battery?

Time taken to fully charge a solar battery using a generator is impacted by various variables. The size of the battery, voltage allowed to reach the battery, and the state of the battery. 

It takes 5-8 hours to fully charge a drained battery. If a charge controller is used during the charging process, it allows only 20% of the current to reach the solar battery. This means it will take more hours to charge a battery with a charge controller.

 If you do not have a generator, electricity is another alternative power source that can you can use to recharge your battery

Steps of charging a solar battery with electricity

If you notice your solar battery is almost drained and you do not have a generator, you can connect your solar battery to electric power output sockets. The process of connecting is simple but you should practice safety tips. Below we have discussed how electricity charges a solar battery. 

  • Connect the solar battery to the power supply.
  • To monitor the flow of current from the power source to the solar battery, connect a working ammeter is connected to the battery. 
  • Connect the battery with a variable voltage output.  
  • Raise the voltage until it is 20% below the rated battery current. 
  • Check the battery temperature constantly and adjust if it is too high.
  • You might decide to charge the battery until it’s fully charged. You can also revive the battery and connect the battery back to a solar panel. 

Do not get used to charging your solar battery with electricity. This is because electricity produces a high current which might damage the battery permanently. Ensure you do not stay closer to the battery when it’s charging. The battery might have conditions that you might not be aware of and explode. 

Frequently Asked Questions

Will a generator overcharge a solar battery?

Any power source if not set up correctly might lead to an overcharge. To prevent the generator from overcharging the battery, use an inverter as a link between the battery and the generator. Keep checking the level of charge until it’s fully charged. 

What size of generator will charge a solar battery?

A generator should be at least two times the size of the inverter. For example, a 6000 watts generator can be used with an inverter with 3000watts. The minimum size of a generator is 8kW and is enough to charge a solar battery. 

Can you use both a solar panel and a generator to charge a solar battery?

No. you cannot use two power sources to charge a battery. Solar batteries require a low current to charge. Using a generator and a solar panel might lead to an overcharge. 

How long does it take for electricity to fully charge a solar battery?

Charging devices using electricity is fast and very reliable. The time is taken to fully charge a battery depends on the quality of the battery, size, and state of the battery. It might take up to 5 hours to charge a fully drained battery. 


Having an alternative power source apart from relying on solar energy is vital. Solar charging is faced with uncertainties. For example, you might have set up the battery wrongly in a way it drains the battery. Sun might disappear for a few days causing discontinuation in your solar charging process. A generator is one of the most effective charging alternatives. You will need less fuel and you can control the charging process.

An inverter is a device that regulates the current that reaches the battery. Most inverters come with connected cables; you will only need to connect to the power source. 

When charging your solar battery with electricity, it is vital to use a charge controller. A charger controller will prevent the high current produced by electricity from damaging the solar battery. 

If all the alternative charging sources cannot revive your solar battery, then it might be dead and you will need to replace it with a new one.

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