Every day, it seems, new technological advances in batteries are enhancing the energy sector across the globe. Not only does this mean an ever-expanding potential for renewable energy, but also a way to stabilize transmission systems and provide mass electrical storage.
In Texas, for example, massive battery storage systems are being used to bridge the gap between the day when solar systems are producing electricity and the night when wind power systems are most proficient.
Luckily for small-scale solar system owners, such as rooftop solar, the advancement of battery technologies has vastly improved system efficiencies, storage capabilities and continues to reduce installation costs.
Pur Solar is keeping up with these advancements, always researching new products and ways to improve current solar system components and practices. That is why most of our solar systems today use lithium ion batteries.
Lithium ion batteries are considered premium for a number of reasons, but all center around one simple fact: They hold more energy. While this concept seems simple enough, it actually is based on multiple factors.
Below we will explain the four major components of a battery’s ability to hold energy and why lithium ion batteries come out on top.
WHAT IS A LITHIUM ION BATTERY?
There are a few different types of solar batteries available today but typically you will only see two: Lithium Ion batteries and Lead Acid batteries. Lead acid batteries are a long trusted battery for solar systems but lithium ion batteries, the newer of the two, are quickly outshining the former.
Without going into the depths of engineering specifications, lithium ion is simply made from the metal lithium while lead acid batteries are made from lead, as their names suggest. The differences between them, though, expand much further than their compositions.
Lithium Ion batteries will cost anywhere from $5000 to $15,000 depending on the system size while lead acid batteries will cost much less. However, the value of the lithium ion battery far extends that of a lead acid battery and here’s why.
Comparing the capacity of batteries is similar to comparing the efficiency of different solar panel types. Monocrystalline panels, for example, are more efficient at creating electricity than polycrystalline.
This means you can produce the same amount of energy with less panels by using monocrystalline types than would be required of polycrystalline panels.
Similarly, the capacity of lithium ion batteries is significantly more than that of lead acid batteries. This means you can use a smaller lithium battery to hold the same amount of energy that a larger lead acid battery would require.
In other words, you get more bang for your buck with lithium ion batteries. If you had two 10 kwh batteries, one of each type, you would be able to store and therefore use more electricity in the lithium ion battery than the lead acid even though the size is technically the same.
DEPTH OF DISCHARGE
The Depth of Discharge refers to the percentage of the battery’s capacity that can be used before the battery should be recharged. Just like your phone battery, using every last drop of energy in your solar battery will significantly shorten its life and damage it’s future capacity.
Consequently, each solar battery comes with a Depth of Discharge (DoD) value determined by its manufacturer. The DoD value for most lithium ion batteries will be roughly 95% or in some cases even more.
Lead acid batteries, howerever, should not be discharged past 50%. This means that on top of the fact that a lead acid battery holds less energy than a lithium ion battery, you can only use half of it.
The percent efficiency, also similar to solar panel efficiency, has to do with how much of the energy put into the battery can be used. Lead acid batteries have an efficiency rating of 80 to 85%, which means that out of all the electricity that is stored in the battery, 80-85% can actually be used.
On the other hand, lithium ion batteries have an efficiency rating of 95%. Another bonus of high efficiency batteries is that they charge faster.
The lifespan of a battery is a complicated and multi-faceted number to determine. There are many factors involved, especially based on the level of discharge you regularly use of your battery.
In other words any given battery will have a certain number of cycles it is estimated to withstand at a certain DoD level. For example, a battery may be rated to have 10,000 cycles when using a DoD rate of 50% or 2,000 cycles at 95%.
Even with the variations in the calculations of battery lifespans, however, lithium batteries average two to three times as long than lead acid.
Related Article: When to Update Your Battery Pack for your Existing Solar System
What Is a MicroInverter?
Another aspect that makes the batteries we use high quality is that they work seamlessly with micro-inverters. All solar systems need some sort of inverter to change the Direct Current (DC) electricity created from the solar system to Alternative Current (AC) which your house uses.
The difference between a regular inverter and a micro-inverter is its size. Instead of having one inverter working for the entire solar system, microinverters can be placed under and connected to a single panel.
Understandably, the first question to come to mind would be “Why would I want so many inverters if only one can do the same job?” That is because each works independently. So in the event that one panel malfunctions, the rest of the system will continue running.
This is a great advantage for solar system owners, essentially protecting the entire system from the nuisance of a single panel’s malfunction. Our batteries are produced by the same manufacturers and providers of the micro-inverters we use, which makes your system components work seamlessly together as one.
At Pur Solar, we stand behind the quality and value of each component in our solar panel installments. We use the Enphase Encharge battery and micro-inverter system and the Sonnen battery, both highly rated by multiple solar review companies.
Want to know more? Call us at (866) 204-9886 or click here to send us a message. We are happy and proud to tell you all about our high quality solar systems.