Battery Selection and PV Installation Performance

Residential Solar and Battery Installation

Introduction

When designing or installing a PV system, it is important to consider the type of energy storage that the system will need. It can be difficult to find reliable information about selecting the appropriate battery for each type of PV system. The following article will consider several critical issues in the selection of batteries for various photovoltaic systems.

System Failure or Underperformance

Photovoltaic systems typically consist of a module or modules, support structure, inverters, controls, cables, storage, and the electrical load. The inverters, controls, cables, etc. are grouped together as a BOS or balance of systems. Modules often last around twenty years with simple cleaning, the BOS components can typically last around ten years using preventative maintenance, and the energy storage can last five years. System failures have generally been attributed to poor design or selection of BOS components. However, battery selection plays a critical role in system functionality and efficiency.

Critical Issues

It is important to consider that batteries are chemical devices that vary widely on environmental conditions, photovoltaic systems, and rate of energy consumption. Predicting the lifetime of the battery is subject to a margin of error due to the following variable conditions:

  • Rate of charge

  • Rate of discharge

  • Frequency regulation

  • Depth of discharge

  • Temperature fluctuations

  • Methods of charge regulation

  • Limits of charge regulation

Inversely, if an improper battery is chosen for a PV system then the system will not perform as advertised and may cause a malfunction in the system altogether. Abusive operational conditions and improper maintenance can make even the most robust battery fail. Therefore, battery performance is directly related to the operational factors of the PV system.

Load Considerations

What is the load requirement of the PV system? This is an important question when determining the sizing of the battery needed. The utilization of the storage system can be calculated by looking at the rate of charge and discharge of the battery. Is the rate of discharge appropriate for the load requirement? Does the storage system provide adequate energy in times of darkness and during short periods of sun exposure? Learn about battery sizing in Greentech Renewables' battery sizing article series. 

Universal Standards for Solar Home Systems

A reference point to consider when selecting a battery is the universal standards set in place for photovoltaic systems. This reference claims that one of the most important considerations in battery selection is cycling, the rate of charge during the day, and discharge at night. Pairing this with the seasonal radiation available and other operating parameters, a battery selection can be made for the PV system. 

In conclusion, it is important to select a suitable battery for the needs of the system itself. Improper battery selection can cause systems to underperform and may cause components of the system to fail completely. Greentech Renewables Engineering services help design and implement commercial solar and storage systems in all 50 states. Contact your local Greentech Renewables location today! 

Published
4 weeks 2 days ago
Written by
Matthew Smith
Support topic
Battery
Support keywords
battery bank
battery
installation best practice
installation methods
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