Among solar lighting manufacturers, there are several different battery technologies used, but each company claims to have the best batteries. With all of the conflicting information in brochures and spec sheets – how can you know what’s really true? We’ve compiled some benefits and drawbacks of the most widely used battery types in the industry to help you make informed decisions.
Nickel-Metal Hydride (NiMH)
NiMH replaced Nickel-cadmium (NiCd) batteries in the marketplace because they don’t contain toxic Cadmium, can store more energy, and retain their maximum energy capacity for longer. They were primarily used for high-power tasks like running power tools until they were supplanted by lithium batteries. If used regularly, NiMH batteries can run reliably for many cycles over an extensive temperature range.
While stronger than NiCd, they’re not as potent as lithium-ion batteries. This means they make devices larger and heavier. NiMH also has high self-discharge, losing about 30% of stored charge per month. In addition, their charge efficiency is relatively low, with 67% of the energy stored being available to be used.
Invented 164 years ago, lead acid batteries are cost-effective, reliable, and widely used. They are great for tight budgets. Plus, they don’t lose their charge quickly, so they’re able to hold power for over a few months.
Unfortunately, lead acid batteries don’t store energy as densely as newer types like lithium-ion, so they are bigger and heavier for the same energy capacity. As a result, larger (and more expensive) poles and foundations are required. Their cycle-life is limited, especially if they’re run down too far or not topped-up every day. The lead they contain is highly toxic, so careful recycling is critical.
The charge efficiency of lead acid batteries is slightly better than NiMH, but only slightly. Lead acid batteries are least efficient at the top of their charge range, which is exactly where they would operate in a solar powered light. In hot conditions, lead acid batteries can dry out, and in cold conditions, lead acid batteries can freeze and become irreversibly. damaged.
Lithium Iron Phosphate (LiFePO4)
Lithium Iron Phosphate (LiFePO4) batteries have impressive benefits. They maintain their capacity for thousands of charge-discharge cycles, which is ideal for electric vehicles and solar powered lighting. They also provide a steady flow of power throughout their use, which is important for devices that need consistent performance. They work well in different temperatures, don’t need much maintenance, and are kinder to the environment, as they don’t contain harmful materials like lead, cobalt, or cadmium. Among lithium batteries, LiFePO4s stand out for their exceptional safety, making them a smart choice for safety-critical uses.
LiFePO4 batteries are not as energy-dense as the lithium batteries used in cell phones and laptops, but they are significantly safer. Extreme cold temperatures can also affect charging performance, but First Light Technologies’ charge controller enables charging of LiFePO4 well below 0 Celcius.
So, What Does First Light Use?
We are committed to providing you with the best quality lighting. That’s why First Light has been using lithium-ion (LiFePO4) batteries since 2017, recognizing that it is the superior battery technology for outdoor solar lighting applications. We work directly with a specialized lithium battery manufacturer to ensure our batteries meet our high-quality standards.
We’ve designed our lights to adapt based on the available solar energy at any particular install location. Through this adaptation, we ensure that our battery always has enough energy to power our lights regardless of overcast days. This is thanks to our smart controllers, which manage the charging cycles. We’ve also tested our lights in varying temperatures: from 0 Fahrenheit (-18°C) in Juneau, Alaska, to 113°F (45°C) in northern Australia!
Batteries can make a difference!
Get in touch to discuss how our batteries keep your light going all night.