Have you bought a new outdoor solar light and want to know how long its battery can last? When should you replace your battery or how often should you? Yes, we will answer these questions in this article so read on!
With the major tech improvement on solar lighting systems, how can one lose interest in this eco-friendly and amazing equipment? Today, solar PV and solar street light manufacturers are on the move to make it more convenient for users to use, maintain and operate. Not only are they more humanized but also available for a cheaper price as compared to in the past.
So if you’re wondering if solar solar light batteries are still expensive and non-economical, think again. With a lot of improvements, this energy storage can now sustain lighting for a week even if the sun didn’t show up. It can also sustain a longer lifespan. What’s more, it doesn’t come with a hefty price tag anymore.
If you have finally opted to buy a solar outdoor light, you want to know how long it would last or how far its battery can go. In this article we are going into that.
What is the Life Expectancy of a Solar Power Battery?
In most cases, a solar battery can last 5-15 years if it’s a lead acid or lithium ion battery. For solar garden lights using nickel-based rechargeable batteries, it can only last 2 to 3 years.
That range will only cut short in between depending on how you maintain your outdoor lights. Some batteries can reach a maximum of 15 years if properly maintained. It also depends on the temperature, type and charge-discharge duration of the battery (which we will discuss later).
If you have a solar PV system, the cell can last for 25 to 30 years. So that means you would have to change batteries 2 to 4 times during its lifetime.
What Factors Affect the Life of Your Solar Battery?
Now let’s take a look at some specific things that can affect your solar battery’s life:
1. Type of Solar Rechargeable Battery
If you’re buying a new outdoor solar light, have a look at which type of battery is used or is specified for that lighting system. Or rather, what type of batteries are used for solar lights? You should have an idea what makes each type unique from each other.
Usually, the cheaper sets of solar garden lights have NiCd or NiMh in them. They are cheaper by the price, but life is relatively shorter.
If you want high-end, durable solar garden lights, you should look for the ones with lithium ion batteries. Nowadays, these batteries are becoming cheaper to manufacture and its technology has developed so you can get your money’s worth. What’s more, the life expectancy is longer.
This means that it might be more practical to buy a higher-priced solar outdoor light with lithium battery than a NiCd solar light.
You would also want to purchase a battery type that can easily lose electrons. This is key as electrons are responsible for seamless charging and discharging. They should come in and out of the battery’s inner system to ensure that it stores and releases electrons properly.
Lithium Ion Battery
Normally, you wouldn’t have to worry much about lithium solar batteries as of the present. They are being heavily improved as a solar battery bank for the outdoors.
Modern solar lighting systems use lithium ion batteries and are much better than its previous models. Majority of the world has made a switch to this battery type, replacing the lead acid, NiCd and NiMH.
Lithium ion battery is also more compact and requires less space than any other battery types. It also has a higher DoD and longer lifespan. It can come with a single battery pack for 3.6V, which can be used in some solar garden lights. This is more advantageous than buying three separate pieces of 1.2V nickel batteries and joining them in series just to obtain a 3.6V battery.
Lead Acid Battery
Lead acid battery has been around for decades, so it’s also a reliable solar battery option. It is also cheaper in cost. HOWEVER, we don’t recommend this for outdoor solar street lighting. Its life is shorter and its depth of discharge is lower than Li-ion.
Nickel Based Battery
If you think your solar lights will not last much longer outdoors anyway, and you wouldn’t want to spend more on lithium ion batteries, then choose nickel-based solar batteries. You have two options: Nickel Cadmium (NiCd) and Nickel Metal Hydride (NiMh).
Between the two, NiMh is preferred because it’s more environmentally-friendly and costs less than NiCd.
An advantage of NiCd is that it has a higher discharge rate and low self-discharge rate. This makes it more robust than NiMh. This also means it has a higher life cycle.
But between the two nickel-based solar batteries, we’d recommend NiMh than NiCd.
2. Solar Battery Maintenance
For solar battery storage, proper maintenance is a must especially for lead acid batteries. If not properly maintained the terminals and parts may easily degrade. This can potentially lower the battery’s life. If you want to prolong the life of your solar battery, make sure to strictly follow maintenance activities such as simple cleaning, applying sealant, etc.
For a certain period of time, they also need to be manually discharged, replenished in a distilled water solution to prolong its life span.
3. Solar Battery Usage
A solar battery’s life can also be dependent on its usage cycle. While lead-acid and lithium solar batteries are efficient in terms of charge-discharge cycle, nickel-based batteries aren’t. So this means they have shorter lifespans.
4. Solar Battery Temperature
As the solar battery’s life is affected by harsh temperatures, you should take precautions when installing outdoor solar lights. To maximize the battery’s life, also make sure you are using the right type of battery for the area where you live. This is because some PV batteries may not perform well under very hot or very cold weather conditions.
For one, lithium batteries are more suitable for low temperature areas reaching -30 deg Celsius. So you can use them if you’re living in countries experiencing very cold climates. The common thing that happens is that batteries exposed to super cold climates need more effort to reach its maximum charge. On the other hand, overheated batteries require less charge.
To address this, some solar lights manufacturers will build a protective enclosure for your outdoor solar battery or bury it underground.
There you have it! In a nutshell, your solar battery can last for a decade depending on the way you use and maintain it. The type of battery you use may also be a game changer. If you opt for cheaper-priced batteries, you may not benefit much on the quality. As Lithium ion is the most preferred battery type for outdoor lighting, we highly recommend you choose this.
At HeiSolar, we manufacture solar street lights with lithium ion batteries. If you want to know more, you may visit our website.
How long do solar batteries last?, How to Replace Solar Light Batteries, Battery Discharge Methods, How to choose the best battery for a solar energy system