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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 report will answer these questions and provide you specific things to check on before buying your new battery (to make certain you get the most bang for the buck)!

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

Part 1)   Quickly compare the three main 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 manufacturer.

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 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 sort of battery that will fit your system.

Lead Acid Batteries

Lead acid batteries are the most commonly used rechargeable battery in the world. They’re also among the longest-used and most dependable batteries in existence.  Compared to the other batteries we’ll discuss in this report; they are the cheapest option but you trade cost for some battery life and depth of discharge.  But for homeowners needing lots of storage for a lesser cost, or if you are just making the move to a solar panel system, lead acid batteries may be a very good option.  They’re the sort of battery we use in the majority of the battery banks in our solar panel systems.

Saltwater batteries are more expensive than lead acid batteries, but also have a greater lifespan.  Unlike lead acid batteries, saltwater batteries are essentially brand new to the market and stay both somewhat untested and harder to come across.  Of the three types of batteries, saltwater has the best depth of discharge, which means you’ll find the most output per fee before needing to recharge.

Lithium Batteries

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

Part 2) Assess the elements of batteries.  Once 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 to your system.  

Cost

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

Battery Life and Warranty

For most systems, a battery will cycle daily, meaning it will charge and drain regularly.  With each cycle, the battery’s ability to hold the identical charge lessens slightly.  So one component to consider is the warranty on the battery which 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 down before needing to recharge the battery without damaging its life.  Certain solar batteries may 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.

Capacity 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 high power can run a massive system for many hours; a battery with low capacity and higher power can run a large system but just for a short time.

Efficiency

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

Manufacturer

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