How Batteries Work With Solar Panels

Feature
By Megan Murphy
11 May 2021

There are three basic solar PV system configurations. In this article, we dive into the two setups that include battery backup storage.

You don’t need a battery to power your home with solar. You can tie into the existing electric grid and feed back any excess electricity your panels create. The utility company reimburses you a one-for-one credit on your monthly bill, through a process called net metering.

HOW DO BATTERIES WORK WITH SOLAR PANELS?

There are two ways to go solar with a battery backup: either by staying tied to the grid, or by going off-grid.

Solar Panels + Home Battery Backup + Grid-tied

This is when a person has solar panels and a battery backup storage option installed (like a Tesla Powerwall or Panasonic Evervolt). This type of system stays tied to the shared utility grid. Any excess energy produced after the battery is full, and beyond what the home is using, is fed back to the grid and credits are applied to the bill through net metering.

Solar Panels + Home Battery Backup (not grid-tied) = Off-Grid

This is when a person has solar panels and a battery backup storage option installed. This system does not stay grid-tied, meaning you have your own “virtual power plant” or “stand-alone system.”

THINGS TO CONSIDER:

1. Electricity → Battery → Home

In both cases, electricity produced from the panels always flows through the batteries first. The system makes sure the battery is always full before it sends electricity to the home. In a grid-tied battery setup, if the home isn’t using all of the electricity being produced, and the battery is full, the extra electricity flows back out to the grid, and credits are applied to the bill through net metering. If you’re completely off-grid, your home is not using all of the electricity being produced, and the battery is full, then nothing happens with the extra electricity.

2. Batteries have a finite amount of storage capacity

Like a cell phone, once you reach maximum storage capacity and you’ve reached 100%, you can’t charge it beyond that. Every time the sun is out, your battery is getting recharged.

3. Battery technology will improve and cost will come down

Billions of dollars are being invested into the R&D of lithium-ion batteries. As more and more people decide to purchase electric vehicles (which use batteries), more and more manufacturers are starting to take this industry very seriously. The same battery technology that’s being used in EVs is the same battery technology that’s being used in battery backup systems for solar PV installs. Progress will be made in the battery space. Technology will get better. Batteries will get denser, and pricing will come down. Know that it is an option now, but again, you can go solar today without a battery backup at all.

RisingSun Solar wants you to know all the available options on the market so you can decide what’s best for your home and your budget. Knowledge is critical in making a big decision like going solar, so do your research and reach out to us with any questions.