Nascar Number 23

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 purchasing your new battery (to make certain you get the most bang for the buck)!

When picking a battery (or batteries) to your solar panel system, there are 3 categories of batteries which work best.    We will do this in 2 parts:

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

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

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

So let’s begin…

There are three battery types that work exceptionally well; however, each battery type has pros and cons. So the first decision to make is the type of battery that will fit your system.

They’re also one of the longest-used and most reliable batteries in existence.  When compared with the other batteries we’ll discuss in this report; they’re the cheapest option but you exchange price for some battery life and depth of discharge.  But for homeowners needing a great deal of storage for a lesser price, or whether you are simply making the transfer to a solar panel system, lead acid batteries may be an excellent option.  They’re the sort of battery we use in most of the battery banks within our solar panel systems.

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

Lithium batteries are the most expensive and the longest lasting of the three kinds of solar batteries.  Their depth of discharge is less than that of a saltwater battery, but more than that of a lead acid battery. Comparing all three options, the lithium ion battery may be the highest rated, but also the most expensive.  A good example of a lithium ion battery is the Tesla Powerwall.

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

Cost

Cost 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 may 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 is going to drain and charge regularly.  With each cycle, the battery’s ability to maintain the same charge lessens slightly.  So one component to consider is the warranty on the battery that guarantees a certain number of cycles of useful life.  But keep in mind that when you use the maintenance and reconditioning methods we teach you at the EZ Battery Reconditioning application, you can extend the life of your batteries.

Length of Discharge

Depth of discharge is how much you can drain the battery before needing to recharge the battery without harming its life.  Particular solar batteries can be depleted farther than others, allowing for more use between charging.  Basically, a battery with a 90% depth of discharge per cycle will provide more battery power per charge than a battery with less.

Ability and Power

Measured in kilowatt hours (kWh), capacity is the amount of energy a battery can store over time. The more capacity a battery has, the more power it can store.   Power is how much energy that a battery can provide at a given moment.  A battery with both 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 only for a brief time.

Efficiency

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

Manufacturer

This may not be a component most would consider, but it is something to focus on.  Like other technology, there are both reputable brands and startup brands.  A trusted brand includes known flaws and advantages; a startup brand can perhaps have better technology, but could also have unknown technological issues.  Depending on your system demands, you may decide to go for a well-reviewed company or one that is brand new to the market.