Can you use solar battery while charging?

By Matt •  Updated: 03/27/22 •  7 min read

Using a solar battery basically mean power is being drawn from the battery. This is what is known as discharging. So when you connect a load to your solar battery, when it is connected to the solar panel technical means you are discharging and charging the battery simultaneously. But how is it possible to discharge and charge a battery simultaneously?

Most solar appliances use a small percentage of the current supplied to the battery by the solar panel. The load will use the current they need to charge and the excess current is used to charge the battery. This however might lead to the battery overheating and causing fire. In this article, we will dive into how you can use the battery while its charging without damaging the battery.

Solar Inverter
Solar Inverter

Can you use solar battery while charging?

You cannot discharge and charge a solar battery simultaneously. One of the process will have to be strong than the other. In most cases, most solar panels are capable of sending large currents to the solar battery for charging. 

When a load is connected to the solar lighting system for charging, they only use very little current. The excess current is used to charge the solar battery. In most cases, the current turnover is solved by the system itself. 

The question whether you can use the solar battery when its charging is a very broad topic. You might connect a load that consumes more power than the current produced. Sometimes, the sun is too dull to provide the usual energy it produces on normal sunny days. All these and other variables below will determination if the solar battery is charging when its in use. 

  1. Amount of current required to charge the connected load

This is the primary reason that affect the charging of a solar battery when the battery is in use. 

  • If the load charging using the solar battery consumes too much current than that flowing into the battery, then the solar battery will be discharging.
  • Suppose the load consist of small appliances like phones or laptops, then the excess current produced by the solar panel will be used to charge the solar battery. 
  1. Time of the day

By now you know solar panel harvest energy from the sun, stored in the solar battery, and then converted into electricity energy to light our home. This means the solar battery only charges during the night. 

Although the solar panel is left connected to the battery at all times, it does not charge at night. So, when you are using the solar battery at night, the battery will not be charging.

  1. Weather condition 

The weather  conditions determine the flow of current to the solar battery. During winter, little or no solar energy is harvested. When you use the solar battery, it discharges despite being connected to the solar panel. 

  1. Type of battery 

Flooded lead-acid  batteries are master of charging when being in use. Most solar batteries overcharge and overheat when they are charging and charging other appliances. Flooded lead-acid batteries are mostly 12V and can withstand large current flowing in and out of the battery. However, the lifespan will gradually decrease over time. To reduce this effect, invest in a high quality solar battery maintainer.

  1. Solar charger controllers

Presence of external solar battery controllers like solar battery tenders and solar batter trickle affects how the battery charges. 

  • A solar battery trickle will improve the charging rate of the solar battery while preventing total discharge.
  • A solar battery tender improves the rate of charging of the battery. It prevents the battery from overcharging. You can also check the level of battery charge to know if its charging or discharging.

Charging the battery while powering other devices might cause some implications to your battery. Your battery might;

  • Overcharge and overheat which might cause an explosion or even more worse things.
  • The rate of discharge of the battery will increase.
  • Decreased battery lifespan.

Solar battery monitors can be helpful if you constantly use the battery when it is charging. You can check the level of the charge of the battery. This will help you know when to stop using the battery to let it charge. 

Can I charge solar battery while connected to the inverter?

An inverter  vital when you are using appliances that use AC. It converts DC into AC. What happens when your solar battery charge runs low? Do you still use an inverter?

An inverter draws the required amount of charge from the solar battery. If you use the right size of the inverter, you will not have any issues with your battery.  It reduces the Amps used while still protecting the solar battery from overheating. You can therefore use an inverter when the solar battery is charging. Provided you are using solar battery controllers. 

Can a solar panel overcharge a battery?

It depends with the size if the battery. Standard solar battery are 12V. When the solar panel produce more than 12V, the battery will be overcharging. Solar battery cannot detect if the battery is fully charged. It continues to send more current to the battery. 

Invest in a high quality solar battery monitors and controllers to protect your solar battery from overcharging.

Frequently Asked Questions (FAQs)

How do I keep the battery charged when not in use?

Use a high quality solar battery trickle. A solar trickle will provide the battery with small amount of charge, reducing chances of the battery draining.

Ensure you store the battery in a cool room and inside a battery box that can be sealed. Store away from reach of children.

Should I let the battery run down before I recharge?

When there is steady supply of solar energy and the battery is fully charged, it can last up to 5days. If you let the battery drain before recharging it, the battery lifespan will decrease gradually. It is however impossible for a solar  battery to run down as the solar panel is always connected to the solar battery. 

Do I leave the solar panel connected to the solar battery overnight?

Yes. Since there is no sunlight energy during the night, the battery cannot be overcharged. A solar panel charges the battery only during the day when there is sunlight. However, if you live in humid areas, ensure you cover the solar panel. This will prevent any moisture sipping inside the solar panel.

Can a solar battery power a refrigerator?

A refrigerator requires steady supply of high current. The current might be too high than the solar panel can harvest.  Solar energy is therefore not ideal when trying to keep your  food products fresh in the refrigerator.

Conclusion

Despite the fact that a solar battery might overcharge, overheat or drain completely, it is impossible to avoid using your solar batter when it is supposed to be charging. You can combine several solar battery monitors and controllers like a solar battery tenders or solar battery trickle to protect your battery from getting damaged. 

Most appliances that can be charged using a solar battery require a small percentage of the current that flows to the solar battery from the solar battery. You can therefore use this appliances with your solar battery when it is charging. Do not use a solar battery to power a refrigerator. A refrigerator will drain your battery.

Matt

I’m Matt, a computer and electronic embedded system developer. Currently, working as an electronic engineer. In my leisure time, I do love to blog about technology stuff. Specially, new advance high tech devices. Portable solar systems are one of topic that I love to investigate. They are becoming more powerful day by day which keep me alert.