Solar Power World

  • Home
  • Top Solar Contractors
  • Articles
    • Most Recent Posts
    • News
      • Latest News Items
      • Solar tariffs
    • Featured
      • Latest Feature Stories
      • Contractor’s Corner
      • Trends in Solar
      • The Solar Explorer
  • Policy
    • Monthly Snapshots
  • Markets
    • Residential
    • Commercial
    • Community Solar
    • Utility
  • Products
    • 2021 Top Products
    • Batteries and Storage
    • Inverters
      • Global Manufacturing Locations
    • Racking and Mounting
    • Software
    • Solar Panels
      • U.S. solar panel manufacturers
      • Global Manufacturing Locations
  • Subscribe
  • Resources
    • About SPW
    • Digital Issues
    • Event Coverage
    • Podcasts
    • Product Manufacturing Locations
      • Global Inverter Manufacturing Locations
      • Global Solar Panel Manufacturing Locations
      • U.S. solar panel manufacturers
    • Solar Classrooms
    • Suppliers
    • Videos
    • Webinars / Digital Events
    • Whitepapers
  • Leadership
    • Vote for the 2022 Leaders!
    • 2021 Winners
    • 2020 Winners
    • 2019 Winners
    • 2018 Winners

How to size a solar battery and why it matters

By Kelsey Misbrener | January 23, 2017

Share

Solar installers have many different options when it comes to batteries, but they aren’t one-size-fits-all. Contractors must be careful not to under- or over-size an energy storage system.

According to Stacey Delzeit, Trojan Battery Co.’s senior applications engineer, if the solar battery bank is undersized, its lifespan will be reduced because the daily depth of discharge will be deeper than necessary. If undersized, the battery bank also may not be able to supply enough energy to support the load.

“We recommend limiting DOD (depth of discharge) to 50%, but the lower the DOD, the better the battery life,” Delzeit said.

On the other hand, if the battery bank is oversized, the PV panels may not be able to fully recharge the batteries.

“Depending on how the backup charge source (generator if available) is set up, a large battery bank can be deeply discharged after a few days of cloudy conditions,” Delzeit said.

If the batteries are deeply discharged, the PV panels will have a large deficit to replenish and may not be able to catch up. An oversized solar battery could also lead to chronic undercharging and poor performance and lifespan.

Some battery manufacturers provide online battery calculators to make the process easier. Here are the three most user-friendly manufacturer tools Solar Power World found:

  1. U.S. Battery
    Search tool allows you to specify exactly what elements of a home should be powered by the battery.solar battery sizing calculator
  1. Trojan Battery Co.
    Users can enter detailed system design parameters like voltage, type of PV system and battery depth of discharge.solar battery sizing calculator
  1. Saft Batteries
    Has a “market” section where users can specify markets like medical, defense or space, then are matched with Saft’s battery recommendations for the best fit.solar battery sizing calculator

Most battery manufacturers will help installers size battery banks–whether online, on the phone or in person. Some just make it easier than others.

About The Author

Kelsey Misbrener

Kelsey is managing editor of Solar Power World and host of the Contractor's Corner podcast.

Comments

  1. Diane Blackwood says

    September 14, 2019 at 12:58 am

    Your article is very informative. Thank you.

    I’m looking for a situation where I want daytime power only from the solar panels
    I’ll use a generator or do without at night.

    How do I figure the minimal battery set up, where the circuit goes off at sundown (or before if its cloudy, etc). I’m really just using the battery to level out load/production during the day.

    Trying to reduce cost and really don’t need power after dark in this situation. I do realize it would depend on load.

    minimum that would work
    (15 amps at 220 V) OR (25 amps at 110 V) NOT both.
    The deluxe version would run
    ( 30 amps at 220 V ) OR ( 15 amps at 220 V and 20 amps at 110 )
    during the time with adequate light only.

    Do you have any suggestions?

    Reply
  2. Fuzail Zubaid Ahmad says

    January 26, 2017 at 1:57 am

    This is really excellent stuff. I am wondering if local Solar PV system suppliers are calculating the battery parameters in the right manner, or using this cookie cutter solution approach.

    Reply

Tell Us What You Think! Cancel reply

Related Articles Read More >

Contractor’s Corner: Got Electric
Quality and reputation help Maryland installer grow during downturn
Op-ed: Let’s close the loop on tariffs to create a sustainable clean energy economy that benefits all
Utility-scale solar panel hail protection
The path toward solar, batteries and generators working together on whole home energy resilience and grid independence

SPW Digital Editions

Solar Power World Digital EditionBrowse the current issue and archived issues of Solar Power World in an easy-to-use, high-quality format. Bookmark, share and interact with the leading solar construction magazine today.

Contractor's Corner Podcast

June 27, 2022
Contractor's Corner: Got Electric
See More >

Solar Policy Snapshot

Solar policy differs across state lines and regions. Click to see our monthly roundup of recent legislation and research throughout the country.

Read More >

Solar Power World
  • Top Solar Contractors
  • Solar Articles
  • Windpower Engineering & Development
  • Battery Power Tips
  • Top Products
  • Leadership
  • About/Contact Us
  • Subscribe
  • Advertising
  • WTWH Media

Copyright © 2022 WTWH Media, LLC. All Rights Reserved. Site Map | Privacy Policy | RSS

Search Solar Power World

  • Home
  • Top Solar Contractors
  • Articles
    • Most Recent Posts
    • News
      • Latest News Items
      • Solar tariffs
    • Featured
      • Latest Feature Stories
      • Contractor’s Corner
      • Trends in Solar
      • The Solar Explorer
  • Policy
    • Monthly Snapshots
  • Markets
    • Residential
    • Commercial
    • Community Solar
    • Utility
  • Products
    • 2021 Top Products
    • Batteries and Storage
    • Inverters
      • Global Manufacturing Locations
    • Racking and Mounting
    • Software
    • Solar Panels
      • U.S. solar panel manufacturers
      • Global Manufacturing Locations
  • Subscribe
  • Resources
    • About SPW
    • Digital Issues
    • Event Coverage
    • Podcasts
    • Product Manufacturing Locations
      • Global Inverter Manufacturing Locations
      • Global Solar Panel Manufacturing Locations
      • U.S. solar panel manufacturers
    • Solar Classrooms
    • Suppliers
    • Videos
    • Webinars / Digital Events
    • Whitepapers
  • Leadership
    • Vote for the 2022 Leaders!
    • 2021 Winners
    • 2020 Winners
    • 2019 Winners
    • 2018 Winners