Batteries are in everything these days. In your electric toothbrush, in the remote control car you bought your kid for Christmas, in your camera. So many appliances require batteries that you can easily find them up front in the checkout line of the grocery store (right next to all the candy and gum that they trap you into buying by conveniently placing it above the conveyor belt). You grab a pack without really thinking about which battery actually performs better because they all cost relatively the same, all say “longest lasting battery” and you’re in a hurry. You don’t really reflect on the quality of the battery when you’re at home flipping through TV channels on the remote. As long as it works, right? 

While that philosophy may work for AA batteries, you probably want to put a bit more thought into the type of battery you integrate with your solar system at home. Two things you’ll definitely want to consider are the type of battery and the functionality of the battery. We’ve compared some of the best batteries in the game below.

When it comes to battery technologies that pair with residential solar systems, there are four main types: lead acid, lithium ion, nickel based and flow. Each has a set of characteristics unique to them.


Lead Acid Batteries

Lead acid batteries are the “old faithful” of the bunch. These batteries have been around since the 1800’s and have been around so long because of their reliability. While they are generally the cheapest option and very reliable, lead acid batteries do have some drawbacks. For example, flooded lead acid batteries have installation limitations because they cannot be placed on their sides since they require ventilation and regular maintenance to ensure that the battery does not leak. Additionally, they have a low depth of discharge, requiring them to be charged more often and giving them a shorter lifespan of about 5 to 10 years. 


Lithium Ion Batteries

If you’ve looked into batteries for your solar array at all, then you’ve most likely heard of a Tesla Powerwall. Tesla Powerwalls are one of the most popular lithium ion batteries on the market today. Lithium ion batteries are the newest to the energy storage world. As the demand for electric vehicles rose, manufacturers saw the potential for lithium ion to be an energy storage solution. They became one of the most widely used battery banks shortly thereafter. These batteries require almost no regular maintenance and have higher energy density, so they can contain more energy in a smaller space than lead acid batteries can. Their higher depth of discharge gives them a lifespan that is typically at least 10 years. Lithium ion batteries are more expensive, but that is largely due to the fact that they enable you to use more of the energy stored within them, making it an effective option for powering your home. There are actually two primary types of lithium ion batteries: lithium nickel manganese cobalt (NMC) and lithium iron phosphate (LFP).


Lithium NMC Batteries

Lithium NMC batteries power electric cars and portable consumer electronics. The Tesla Powerwall is a lithium NMC battery. Because this type of battery is made of cobalt, it is lighter weight and more powerful. Its cobalt composition also makes it highly combustible though. Rest assured, those of you with lithium NMC batteries, the likelihood of your battery catching on fire if installed correctly is practically zero. 


LFP Batteries

LFP batteries, such as the Enphase, have long life cycles and are more stable than lithium NMC batteries because of the additional aluminum in them. They can operate at much lower temperatures than other batteries, making them an ideal choice for most homes. Their ability to withstand high voltage use for extended periods of time gives them higher thermal stability; ergo, a lower risk of electric shortages and even fires.


Nickel Based Batteries

Nickel-cadmium batteries are not nearly as commonly used as lead acid or lithium ion batteries. They were first introduced in the late 1800s, but got an upgrade in the 1980s that increased their energy storage capabilities. These batteries are highly durable, can operate at extreme temperatures and require little to no maintenance; however, the cadmium they contain is highly toxic. The use of cadmium is actually prohibited in some countries and they are hard batteries to dispose of. Furthermore, their ability to hold a charge is limited by their propensity for acquiring the memory effect. 


Flow Batteries

One of the newer energy storage technologies, flow batteries contain a water-based electrolyte liquid that flows between two separate chambers, or tanks, within the battery. These batteries have recently become increasingly popular. Their 100% depth of discharge allows all the energy contained within the battery to be used without detriment to the battery’s health. These low-maintenance batteries also have the longest lifespan of about 30 years. Flow batteries are the most expensive battery option by far. Their relatively low storage capacity requires the battery itself to be fairly large so they can hold a substantial amount of energy. Their low charge and discharge rates contribute to their need to be larger in size as well. 

All in all, the best batteries for residencies are lithium ion batteries. They can hold enormous amounts of energy in small spaces and have high efficiencies because they discharge most of their stored energy. Lithium ion batteries are also the most popular option in society today.  If you’re unsure of which battery type would be best for your home, don’t hesitate to call Firefly Solar.