Should you need to store the solar battery when not in use? How to store them?

Solar energy is one of the best solutions for the increasing energy crisis. Because of that many types of equipment had come to the market. Solar-powered equipment may work differently from each other. But we know that many devices such as house solar panels, solar home lights, solar garden lights do have solar batteries to store energy. Usually, rechargeable batteries are used as solar batteries. Nickel-based batteries, lead-acid batteries, and lithium-ion batteries are commonly used as solar batteries.

When you are not using your solar device for prolonged periods, it is better if you can take out the battery and store it separately. By doing so you can protect your battery and the device too.

When you should consider storing your devices?

There are some instances that you have to keep your solar devices inside your house.

• When there is no sunlight at all for days there is no point in keeping them out.

• If the weather is bad (snowstorms, hurricanes, etc) physical damages can be happened to your devices by fallen trees or branches if you left the devices outside. So you may have to store them inside.

• Also if you are leaving out for days you have to store it inside.

• Also, extreme temperatures can affect your solar battery so it is better if you store it inside.

How extreme cold temperatures affect your battery?

Even though solar panels generate energy more effectively at cold temperatures, batteries lose capacity at cold temperatures. The ideal temperature of the batteries is 10^oC – 30^oC. At extreme temperatures, the efficiency of the batteries will be drastically affected. Especially in extremely cold temperatures. So this will decrease the effectiveness of your system. So it is better to store it inside to avoid any damages to your batteries and the system in extremely cold temperatures. Read also: what happens to batteries at higher temperatures?

Why you should store the batteries separately?

One of the reasons is rechargeable batteries do self-discharge even when they are not in use. That means the chemical reactions are still happening inside the battery. If you leave it unattended for days there can be chemical reactions that may result in leakage of chemicals. This can lead to corrosion of the battery and the battery terminals too. Also if you left the battery unattended for long period there can be physical damages that happened to the batteries without you noticing. So this can cause any fire hazards or any leakage of toxic substances.

What you should know before storing your batteries?

• Maximum storage duration.
• The storage temperature – for most batteries the recommended temperature is 15^oC this can be varying for different varieties.
• You have to check the voltage and the specific gravity from time to time.
• When to charge your batteries.
• Potential damages to the battery during the storage period.
• You cannot store batteries together.
• Always follow the manual of the battery to avoid any mistakes.

How to store solar batteries?

Lead-acid battery

These batteries can be stored for up to 2 years. The battery should be charged when the battery’s charge falls up to a 70% charge state. This can be varying for different batteries. So it is better if you check the manual to verify the readings. You also should check the voltage and the specific gravity. These can get by using the readings of the manual.

Damages that can happen in low charge state

• Sulfation – an oxidized layer will be accumulated on the negative plate. This will disturb the normal current flow in your battery. To reactivate sulfated batteries you should apply an elevated voltage to the batteries. When applied this voltage to the battery for more than one hour the sulfur crystals will gradually become active. Then this will allow the current flow. But to avoid any damages to your batteries you should apply low ampere value when charging.

Nickel-based batteries (NiCd/NiMH)

These batteries can be stored up to 3 – 5 years. It is better if you store these batteries at 40% charge state. But this can be kept at a zero charge state without any damages to the batteries. But if you left the batteries with at least a small amount of charge it is easier to recover/ reactivate the batteries. You can reactivate the batteries with food capacities even after a prolonged period. The stored space should be dry and cold.

Lithium-ion

These batteries can be stored for up to ten years. But the charge state should be kept at 40%. If the voltage becomes less than 2v per cell you can not keep it for any length of time. If the voltage becomes less than 2v/cell copper shunts will be started forming inside the battery cells. This increases the self-discharge and can result in a short circuit. If you recharge these batteries it will result in excessive heating and can become unstable. So it is safe if you discard the batteries which kept less than 2v/cell for more than one week.

Disadvantages of storing your batteries for a prolonged period

• Loss of capacity/ aging of the batteries. Even though you are not using the battery it loses its capacity with time. So if you did not use the batteries for a prolonged time that means that the time you can use those batteries will be reduced.

• You must do regular maintenance. Also, you have to check the voltage, charge state, and specific gravity regularly. Sometimes doing these can be exhausting for you. But to avoid any damages to the batteries you must do these.

• You have to maintain the storage conditions such as proper temperature, humidity. etc properly during the stored time to prevent damages to the batteries. Some times this can cost you.

• You cannot store batteries together. So you may need separate spaces for the batteries. This increases the cost and you have to find more space to store your batteries.

| Conclusion |

It is not practical to keep solar devices outside all the time. There are some instances where you may need to store the solar system/ solar devices inside. This can be for short period or a prolonged period. If you are storing these devices for a prolonged period it is safer to take out the batteries and store them separately to avoid any damages to the equipment as replacing the whole device is much more expensive than replacing the battery.

When storing the batteries you must have a clear understanding of the storage requirements and many more things. You can always refer to the manual of the battery for storage instruction or you can get help from professionals.