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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 greater than another?  If so, this report will answer these questions and give you specific things to check on before buying your new battery (to make certain 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 which work best.    We will do this in two parts:

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

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

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

So let’s get started…

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.

Lead Acid Batteries

They’re also one of the longest-used and most reliable batteries in existence.  When compared with the other batteries we will 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 lower price, or if you are simply making the move to a solar panel system, lead acid batteries might be a very good option.  They’re the type of battery we use in most of the battery banks in 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 industry and remain 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 find 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.  Comparing all three options, the lithium battery is probably the highest rated, but also the most expensive.  A good example of a lithium ion battery is the Tesla Powerwall.

Part 2) Assess the elements of batteries.  As soon as you’ve chosen the best battery type for your own solar panel or off-grid system (that meets your system’s needs), there are components to explore to find the ideal battery for 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 may be overkill for your system so the most expensive battery might not be the ideal choice always.

Battery Life and Warranty

For most systems, a battery will cycle every day, meaning it is going to charge and drain regularly.  With each cycle, the battery’s ability to hold the same charge lessens slightly.  So 1 component to consider is the warranty on the battery that guarantees a specific 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 program, 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.  Essentially, a battery with a 90% depth of discharge per cycle provides 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 a battery can provide at a certain moment.  A battery with both a high capacity and higher power can run a large system for several hours; a battery with low capacity and high power can operate a large system but just for a short time.

Efficiency

Efficiency is the amount of energy used compared to the amount of energy it took to save said energy.  Batteries require power to control and efficacy compares the energy taken to control a battery together with the amount of energy that the charged battery generates. 

Manufacturer

This might not be a component most would consider, but it is something to focus on.  As with other technology, there are both reputable brands and startup brands.  A trusted brand comes with known defects and benefits; a start-up brand can perhaps have better technology, but can also have unknown technological issues.  Based upon your system demands, you might decide to go for a well-reviewed company or one that is brand new to the market.