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How To Pick Out The Best Battery For a Solar Panel System, Battery Bank, or Off-Grid System

Or have you wondered what makes one deep cycle battery better than another?  If so, this article will answer these questions and provide you specific things to check on before buying your new battery (to ensure you get the most bang for the buck)!

When choosing a battery (or batteries) for your solar panel system, there are three categories of batteries that work best.    We’ll do this in two parts:

Part 1)   Quickly compare the three main kinds of solar batteries (lead acid, saltwater, and lithium).   And,

Part 2)   Assess the components of batteries, such as: depth of discharge, capacity and power, efficiency, battery life, and maker.

By the conclusion of this article you will know just how to pick out the ideal battery to your own solar panel system!

So let’s begin…

So the first decision to make is the sort of battery that will fit your system.

Lead Acid Batteries

They’re also among the longest-used and most dependable batteries in existence.  When compared with the other batteries we’ll discuss in this report; they’re the cheapest option but you exchange cost for some battery life and depth of discharge.  But for homeowners needing lots of storage for a lower cost, or if you are just making the transfer to a solar panel system, lead acid batteries might be an excellent option.  They’re the sort of battery we use in the majority of the battery banks within our solar panel systems.

Saltwater batteries are more expensive than lead acid batteries, but also have a better lifespan.  Unlike lead acid batteries, saltwater batteries are essentially brand new to the market and stay both somewhat untested and more difficult to come across.  Of the 3 types of batteries, saltwater has the greatest depth of discharge, so you’ll get the most output per charge before needing to recharge.

Lithium Batteries

Lithium batteries are the most expensive and the longest lasting of the three types of solar batteries.  Comparing all three choices, the lithium ion battery is probably the highest rated, but also the most expensive.  An example of a lithium ion battery is the Tesla Powerwall.

Part 2) Assess the elements of batteries.  As soon as you’ve picked the best battery type for your own solar panel or off-grid system (that meets your system’s needs), there are elements to research to find the perfect battery to your system.  

Cost

Price is probably one of the more obvious elements.  But the old saying,”you get what you pay for” holds true when buying batteries as well.  In some instances though, certain batteries could be overkill for your system so the most expensive battery might not be the best choice always.

For most systems, a battery will cycle daily, meaning it will charge and drain regularly.  With each cycle, the battery’s ability to maintain the identical charge lessens slightly.  So 1 component to consider is the guarantee on the battery that guarantees a certain number of cycles of useful life.  But keep in mind that if you use the maintenance and reconditioning methods we teach you in the EZ Battery Reconditioning application, you can extend the life of your batteries.

Depth of Discharge

Length of release is how much you can drain the battery before needing to recharge the battery without damaging its life.  Certain solar batteries can be depleted further than others, allowing for more use between charging.  Basically, a battery with a 90% depth of discharge per cycle provides more battery power per charge than a battery with less.

Ability and Power

The more capacity a battery has, the more power it can store.   Power is how much energy that a battery can provide at a certain moment.  A battery with a high capacity and higher power can run a large system for many hours; a battery with low capacity and high power can run a large system but just for a brief time.

Efficiency

Efficiency is the amount of energy used compared to the quantity of energy it took to store said energy.  Batteries require power to control and efficiency compares the energy taken to charge a battery with the amount of energy which the charged battery produces.  The higher the efficiency, the more cost-effective the battery.

Manufacturer

This may not be a part most would consider, but it is something to focus on.  Like other technologies, there are both trusted brands and startup brands.  A trusted brand includes known flaws and benefits; a startup brand can perhaps have better technology, but could also have unknown technological issues.  Based on your system needs, you might decide to go with a well-reviewed firm or one that is brand new to the market.