What Type of Batteries are Best for Solar Lights? (Updated 2022)

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Solar lights are pretty much favored over AC powered lights. They are cordless solutions for ‘wherever and whenever’ situations. To keep it running, you’ll need the right solar batteries to match your lighting system requirements.

Want to find out which types of batteries are the most suitable for your solar lights? Here are the best battery types for solar in the market.

How Many Types of Solar Batteries Are There?

If you are planning to install a solar lighting system, or switching to another energy storage bank, you’ll have several options. 

Generally, there are 4 main types of batteries for large capacity solar lights. For smaller solar lights like garden lights, yard lights, bollard lights, fairy lights, two battery types are available. 

Have a look at these below and see which fits your lighting equipment the best.

Solar Light Type	Battery Type That Can Be Used	Depth of discharge
Solar Street Light/Solar Garden Light	Lithium ion battery	80-90%
	Lithium iron phosphate battery	80-90%
	Lead Acid battery	60%
	Flow Battery	100%
Solar Bollard Light, Solar Fairy Light, Solar Garden Light, Solar Yard Light	Nickel Cadmium (NiCd)	60%
	Nickel Metal Hydride (NiMH)	30-40%

Related Article: What is Depth of Discharge (DOD) and how does it affect a battery?

Best Rechargeable Batteries for Solar Street Lights

Solar light batteries are often deep cycle batteries. These types of batteries are rechargeable and sustainable, which make them widely used in the renewable energy sector.

Deep cycle batteries have cycle times 2 to 3 times higher than automotive batteries and they can extend for up to 3000 cycle times.

What’s more, you only need to replace them for only 5 to 7 years depending on the type of deep cycle battery you use. Here are two of the most common types of deep-cycle batteries.

Valve Regulated Lead Acid Battery (VRLA Battery)

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Valve Regulated Lead-acid batteries are the oldest and the most common batteries for solar street lighting. They are also the cheapest in price. You may find lead-acid batteries common in cars. There are two types of VRLA batteries – AGM and GEL.

Generally, they are heavier than other battery types and have a shorter life cycle. That is why most manufacturers prefer Lithium batteries.

Once in a while, they have to be replenished in a distilled water solution to prolong its life span. Lead-acid batteries can be inefficient in terms of charge and discharge cycles.

The upside to this type of battery is that they are inexpensive and reliable only if you follow its charging and discharging cycle properly. For solar street lights, the usual price of VRLA battery 150Ah is around $150 to $400 depending on the battery brand.

Lithium Battery

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Lithium batteries are the most common types of solar rechargeable batteries for solar LED street lighting. They sustain almost 4 times discharge, apparently high for batteries. They can also live up to 5 times longer than lead-acid batteries.

They are practically the best type of battery for solar panels, as well as solar lighting systems.

Lithium batteries do not require frequent maintenance like lead-acid batteries. This makes it convenient for users. Most batteries can only sustain 500 to 800 charge-discharge cycle times. For Lithium batteries, they can substantially sustain up to 2,000 cycles.

Lithium batteries are durable as well. They can store up energy for solar lights to be used for many winter or rainy days. Price of Lithium Batteries may range between $400 to $850.

Lithium Ion Battery and Lithium Iron Phosphate Battery: Which One to Choose?

There are two types of lithium batteries used in the solar industry. Many people are actually confused about which lithium battery type is better for their application. Here we discuss how each type can benefit you.

Below you can find the difference between Li-ion and LiFePO4.

	Lithium Ion Battery (Li-ion)	Lithium Iron Phosphate (LiFePO4) Battery
Size	18 x 65 mm	26 x 65 mm
Nominal Voltage	3.7V	3.2V
Voltage of Battery Set	12V	12.8V
Cost	Cheaper in price	More expensive
Working temperature	-30 to 65 Celsius	-10 to 75 Celsius
Cycle Life	1000 times	2000 times

Battery Performance

In terms of battery performance, it would depend on the average temperature in your area. As seen in the table above, Lithium Ion can be more suitable for low temperature areas reaching -30 deg Celsius. Hence, they are more appropriately used in the northern hemisphere countries. These countries experience extremely cold climates.

Safety

In terms of safety, LiFePO4 is generally safer to use for solar street lighting than Li-ion. This is because LiFePO4 has a more stabilized chemical composition than Li-ion .

Durability

Lithium iron can sustain longer charge/discharge cycles than Li-ion, as seen in the table above. This makes it more durable than lithium ion.

Flow Battery

Zinc Bromine Flow batteries or Redox Flow batteries are one of the newest battery types developed for solar equipment. These batteries contain zinc bromide water-based solutions stored in two compartments. The newest installment by Gelion is a gel type zinc bromine flow battery which is cheaper in price.

For this type of battery, the charging and discharging processes take place between two storages. When the battery is charging, zinc undergoes electroplating and transforms to zinc bromine. When it discharges, the zinc which are plated on the negative electrodes dissolve in the electrolyte. Then it will be plated again at the next charge cycle. 

The major advantage of flow batteries over lead acid and lithium batteries is that they have 100% depth-of-discharge. 

This means you can make full use of its energy in a cycle without worrying about the life of the battery. 

In comparison with lithium batteries, you can only use up to 80 to 90% of its energy per cycle as going further can potentially decrease its life.

However, since this is a new-found battery technology, there’s only a limited amount of suppliers offering this product. It’s also more expensive than lithium batteries.

Rechargeable Batteries for Solar Garden Lights

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For solar garden lights, we can find two of the most common rechargeable batteries below.

Nickel Cadmium (NiCd)

Nickel cadmium battery for solar yard lights and garden lights are often rated at 1.2 V / 500 to 900mA. This type of battery requires minimum management systems and can last for one to two years. A great thing about NiCd is it doesn’t need frequent maintenance as compared with other garden light battery types.

NiCd can also be used for solar panel battery systems because of their flexibility in extremely large temperature differences. The downside of NiCd is that it needs to be disposed of properly as it emits harmful toxins at the end of its life.

Nickel Metal Hydride (NiMH)

This brings us to another solar garden light option, which is more environmentally-friendly. NiMH is much more eco-friendly than NiCd battery.

Nickel Metal Hydride battery for solar garden lights are often rated at 1.2 V /1000 to 2000mA. NiMH has a larger capacity than its counterpart. This means that NiMH can power your solar garden light longer than NiCd.

Unlike NiCd, NiMH doesn’t have a memory effect; meaning it would easily remember to charge at its full capacity over time.

Wrapping Up

Whether you are looking for solar street light batteries or solar garden lights batteries, we hope that this article has helped you choose the best battery type.

At HeiSolar, we develop our LiFePO4 with management systems for high and low temperature applications. This is to allow efficient monitoring and optimization of the overall battery performance of our solar street lights. Moreover, the battery’s life can be fully optimized up to its end of life.

If you want to know more about solar products and solutions, you may contact us for more information.