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Solar Batteries: A Beginner's Guide

In this article, you will learn all about Solar Batteries.

You'll gain knowledge about the different types of solar batteries, how they integrate into a Solar System, the number you'll need, and other critical details.

Here’s the breakdown:

Let’s get started.

Chapter 1

What Are Solar Batteries

Let's start at the beginning

Solar Batteries store power, either solar power generated from your solar panels or grid-supplied power, ensuring you have electricity when it's nighttime or when the grid fails.

However, solar batteries do not work on their own. They require additional equipment to manage the charge and discharge rate, maintain the health of your battery bank, and convert DC stored power to AC power needed for household appliances.

You typically employ a solar battery in one of two scenarios, either in a Solar Power Kit or a Load Shedding Kit.

Load Shedding Kit

A Load Shedding Kit contains a Solar Inverter, a Battery Bank, and peripherals such as disconnect switches and wiring. Load Shedding Kits come without panels, but you can add panels later if desired.

Solar Batteries store DC (Direct Current) power, but homes use AC (Alternating Current).

The inverter converts grid-supplied AC power to DC power when your battery is charging. When using the power stored in your battery, the inverter converts DC power back to usable AC power.

Solar Power Kit

As its name implies, a Solar Power Kit includes a Solar Inverter, Battery Bank, Peripherals, and Solar Panels.

Solar Power Kits supplement your daily usage with freely produced solar power and supply power during load shedding, thanks to the battery bank.

Typically, your Solar Panels charge your battery bank during the day, allowing you to use the stored solar power in the evenings or during grid failures.

Solar Power Kits save you money on electricity, unlike Load Shedding Kits.

Chapter 2

Fundamentals

Solar terminology explained

Understanding the terms used in this guide is crucial as they help you in sizing your battery bank. If you already know the basics, skip to Chapter 3.

What does Deep-Cycle mean?

The term "Deep-Cycle" refers to Depth Of Discharge (DOD). Deep-Cycle Solar Batteries are designed to regularly discharge most of their capacity. The depth of discharge varies depending on the battery type.

DOD

DOD (Depth of Discharge) indicates how much of the battery's capacity can be utilized. A typical Lead-Acid Battery has a DOD of 50%, while Lithium-ion Solar Batteries have a DOD of 80-100%, crucial for calculating your solar battery needs.

Chapter 3

Which Types Are Best For Solar Power?

In essence, there are 2 main types of Solar Batteries: Lead Acid and Lithium-ion

Sealed Lead Acid

Sealed Lead Acid is an upgrade to the flooded version and eliminates maintenance needs.

However, they have a shorter lifespan compared to Lithium-ion Batteries, making them more costly in the long run as they typically need replacement every 3 years.

How do Lead Acid Batteries work?

Absorbent Glass Mat (AGM) batteries handle higher temperatures and have a lower self-discharge when idle. The cells offer lower resistance than conventional cells; they don’t leak and don’t need to be mounted upright.

New AGM batteries should not be connected in series with older batteries, as this will damage the newer one.

Pros

• Completely sealed, no acid leak risk
• Maintenance-free
• Can be mounted in any orientation
• Quick charging with lower voltage
• Lower initial cost

Cons

• Short lifespan, around 3-5 years (depending on the brand)
• Frequent replacement needed
• Only 50% depth of discharge is recommended

Lithium-ion

The most efficient battery on the market, Lithium-ion technology is the future of solar storage. These batteries waste significantly less power during charging and discharging. They also have a longer lifespan and utilize their capacity more efficiently.

Completely maintenance-free, these batteries are lighter, smaller, and generate less heat compared to Lead Acid batteries, making them ideal for space-constrained setups.

Easy, versatile Installation

Lithium-ion batteries come in various sizes and are easy to install. Adding new batteries later is simple; you just add them to your existing battery pack.

You also have a choice in their installation: wall-mounted, floor-mounted, or rack-mounted, providing flexibility. For rack-mounted batteries, a cabinet option is also available.

Pros

• Maintenance-free
• Lighter and smaller
• Can be mounted in any orientation
• Produce more cycles (6000-10000)
• Can deliver 100% of stored energy
• Lifespan between 10-20 years
• High charging and discharging efficiency, over 95%

Cons

• Higher initial cost

View our Lithium-ion Range →

Chapter 4

How to Size a Battery Bank

In 3 easy steps

To begin, it’s crucial to check the power ratings of your appliances to ensure your battery bank is adequately sized for your needs.

Step 1

Add the power ratings of all the appliances you’d like to run off your solar battery bank. It’s always a good idea to check each appliance's ratings for an accurate measurement of your usage.

Step 2

Next, calculate how long you typically use these appliances. Different appliances have varying usage times; for instance, a TV might run for 4 hours while a microwave might be used for just 3 minutes.

This step relies entirely on your specific usage patterns.

Step 3

Consider how you will use your solar battery: during load shedding, non-production times, or both?

Non-Production Time Guidelines

Below are guidelines to help you determine how many hours you’d like to run your appliances from your battery bank.

Load Shedding Usage

In some areas, individuals can experience 2.5 hours of load shedding, while in other regions, load shedding can last up to 4 hours. It's essential to factor in these times.

Evening Usage

The average evening usage is around 4 hours for appliances commonly used between coming home from work and going to bed, typically from 18:00 to 22:00.

Nighttime Usage

Assuming a good night’s sleep of 8 hours, essential appliances like fridges and alarms often continue running.

Morning Usage

Morning routines use a lot of power due to appliances like kettles, toasters, microwaves, and hairdryers, which draw large amounts of power. Usually from 06:00 to 10:00, solar power alone might not cover the load, so a sufficiently large battery is advisable.

As a general rule, be mindful of what you are running off your battery bank, though mornings may require prioritizing essential appliances.

In the next section, we’ll explore a case study to show you how to calculate your battery needs.

Chapter 5

Calculating Your Usage Data

Let's work out our usage!

Based on my home, I’ll break down our appliances, their ratings, how often they're used, and how long they're used over 16 hours.

I've divided this into three sections: Mornings, Evenings, and Nights.

Mornings

Total: 3399W

Evenings

Total: 3533W

Nighttime

Total: 1678W

Case Study Findings

Combining the totals for each time frame determines my family’s overall usage and battery needs to cover 100% of our load using a solar battery bank.

The combined total is 8610W or 8.61kW.

To choose a battery, consider the battery’s DOD (Depth of Discharge). If I choose an 80% DOD battery, subtract 20% from the overall battery rating.

I could consider options like PylonTech US3000C Batteries, which give me 9.975kWh at 95% DOD, or Dyness 3.6kWh Batteries providing 8.645kWh at 80% DOD.

Chapter 6

Which Solar Battery Brands Are Best?

Here’s our recommended selection of brands

As with other components, the brand of the battery is closely related to its quality. Solar Batteries are no different in this regard.

PylonTech

Pylon Technologies, Co. Ltd., founded in 2009, is a pioneer in LFP (lithium iron phosphate) battery technology deployed in ESS (energy storage systems).

Pylontech’s batteries are used in high-end vehicles, cloud computing systems, telecom power