The battery is one of the most important components in a solar lights system. In this article, we’ll introduce the different types of battery in common use, and explain what to look for when it comes to replacing your batteries, upgrading your batteries, or comparing the merits of different solar lights.
Types of batteries in solar lights
NiMH
NiMH batteries are commonly used in smaller solar lights – the kind that you might use to light up a pathway – rather than flood lights that you might use for security purposes.
Some solar lights use NiMH batteries which are a bit different from the NiCd type, however, you can use them interchangeably. The NiMH type can easily be disposed of without causing much harm to the environment, and they recharge more times than the NiCd types.
Its energy density is twice that one of the NiCd types with a discharge cycle that varies from 500 to 3,000. They can be rapidly charged within an hour, but have a high risk of discharge three times more than NiCd ones.
One thing that some people like about NiMH batteries is that they come in standard sizes such as AA and AAA, which means that if you needed to , you could use them in another device.
NiCd
NiCD (nickel cadmium) batteries were a dominant battery technology for decades but are used less frequently these days. One reason for this is concern for the environment; cadmium is a toxic metal and so these batteries must be properly disposed of, meaning not in a landfill.
On the positive side, NiCD batteries perform well in low temperatures and have a high cycle count, meaning they can be recharged many times. This gives NiCD batteries a lower cost per cycle ratio than other battery types.
Like NiMH batteries, they are typically used where lower or softer illumination is acceptable or advantageous, such as in deck lights, rather than flood or spot lights.
Lithium Ion (Li-ion)
The lithium ion battery is a newer technology. They were developed in the 1980’s and first became commercially available in the early 90’s. They are now the standard in solar lights that require high output, such as flood lights and home security lights with motion sensors.
An important reason to favor li-ion batteries is that they charge faster than NiMH batteries. So on days with limited sunlight or shorter daylight hours, a lithium ion battery will be better able to make the most of the available light.
Lithium ion batteries are low maintenance and long lasting. While more costly than NiCD and NiMH, they perform better across a wider temperature range and have a higher energy density, providing brighter or longer lasting light.
Lead Acid Batteries
These batteries are also known as flooded lead acid batteries or wet cell lead acid batteries. They are the oldest type of rechargeable batteries. Their main application when it comes to solar lights is to power flood lights in an off-grid situation.
These are deep cycle batteries, designed to discharge 80% or more of their stored energy on a regular or frequent basis. They tend to be large and heavy (roughly the size of a car battery) and are designed to provide steady current over a relatively long period of time. (Contrast this with the starter battery in a car, which is designed to provide a short, intense burst of power before going into recharge mode after the engine has started.) Deep cycle lead acid batteries are commonly used by owners of recreational vehicles (RVs) or others who live or work off grid.
Battery Capacity
Pay attention to the capacity rating, which is indicated by the mAh rating (mAh stands for milliamp hours). Any good description of a battery will include descriptions like “600 mAh” or “1800mAh”. Bigger is better. A rating of 1800 mAh means that the battery can provide current at 1800 amps for 1 hour, or 180 amps for 10 hours. The higher the mAh rating, the longer the battery can run.
In fact, simply upgrading the battery can make a dramatic difference in the performance of the system.
Fully charged batteries can provide 10 to 12 hours of illumination during the night.
Why You Should Opt for Rechargeable Batteries Than Non-Rechargeable Ones (Alkaline)
- Alkaline batteries tend to work for a short time and severely corrode the battery terminal which prevents any power from reaching the solar light
- It is possible to clean the corrosive effects of the non-rechargeable batteries, but may pose a risk to the light’s inner workings if any excess water seeps through
- The damage and results are normally irreversible and will lead to the demise of your solar panel
Tips on How to Buy the Best Battery for Your Solar Panels
- You should opt for batteries with high capacity ratings (mAh). The higher it is, the more long-lasting
- Buy the battery that fits your budget because they vary depending on the manufacturers
- The type of battery you buy will ensure optimal performance of your solar lights either in the form of nickel-metal hydride (NiMH) or nickel-cadmium (NiCd) batteries
- NiMH batteries tend to charge to full capacity, but the NiCd types don’t charge fully because of the cyclic memory effect, which makes them remember periods of low charging and charge to the same capacity
- NiCd batteries contain cadmium which is a heavy metal element which is very toxic. The leaking batteries need to be handled with at most care because any contact with cadmium can lead to its absorption in the body. They need to be disposed off well in designated recycling stations
Garden Solar Light Batteries
Always check all the components of the solar light. When a layer of dirt settles on the panel it prevents direct sunlight from getting through. Therefore, the solar panels need regular cleaning and should be tilted in a way they can best absorb sunlight.
Solar lights have a circuit board that acts as a sensor and sends the charge from the solar panel to the battery. When it’s dark, the circuit board senses and stops charging the battery.
Always check for signs of damage on the battery. The damage can include water damage, rust or broken wires and corrosion. When replacing batteries you need to with batteries of the same voltage and capacity.
If you have to change the battery capacity, choose one that is lower and not higher than the previous capacity, but the voltage should remain constant.
When the solar lights come on during the day it means that the light sensor is working well. You should also take caution not to put non-rechargeable batteries in a rechargeable solar light.
Conclusion
So do you need special batteries for solar lights? Well, yes, as you can see above, there are various options. It is important to fully charge the batteries before using them to ensure they last for 8 to 12 hours.
The batteries should also be replaced after 2 years so that they can operate within maximum capacity. The panels should always be titled at angles to absorb maximum light. You should read the instructions for your solar panels to ensure you use the right battery.
