• Team GreenLancer

Solar Powered Battery Backup Vs. Generator

Updated: Feb 26

Residential Solar PV Panels on a House

With an estimated 3 million people losing power due to winter weather during the early February power outages in Texas, homeowners in Texas and around the nation are beginning to question where they get their energy from and how they can be better prepared in the future.

When the grid goes down at such a massive scale, it creates harsh and dangerous conditions. Homeowners who want to get ahead of this have a few options; they can install a diesel powered generator, or install a solar array with battery storage. We detail the differences of the two in this article.

** GreenLancer offers design and engineering for both solar, battery and generators. Installers can sign up for free and shop a catalog on fast turnaround, on demand, standardized services.

Battery vs. Generator | Which is best for me?

Comparing generators to batteries is a case of apples and oranges. To make the right decision, first establish what your energy goals are. Both applications will be a considerable investment, so if price and payback is your top priority, a battery might be your best option. “ROI” is a common word in renewable energy, and rightfully so. It is a common misconception that there is no ROI on a battery. We disagree. Your battery can be configured so that it is used daily, unlike a diesel generator that only runs during a grid failure. What this means is that you have the ability to take electricity from your battery every day before taking electricity from the grid.

We like to think of a battery as an “external hard drive” that is always ready to go and keep you backed up. When the grid is up and running, it acts as “cloud storage” providing you power when you have maxed out your “hard drive”. However, using a battery on a daily basis comes at a risk. If your battery is configured to the maximum DOD (Depth of Discharge), you run the risk of the battery dying and the grid failing overnight. If there is no solar attached to the battery or no sunlight during the outage, the battery may not be able to recharge itself. If ROI is not your primary goal, then configuring a battery to remain at 100% and only work in the event of an outage is your best option.

A traditional generator has it’s advantages too. It will run day or night, sunny or cloudy. As long as you have the ability to refuel, you don’t have to worry about running out of power during an outage. If ROI is your primary goal, then this is not the option for you. The only time you will ever generate a return is during a grid failure. A power outage is like all bad things in life; it feels like it lasts a lot longer than it actually does. In the United States, there is an average of 2.5 grid failures per month averaging less than 48 hours (Inside Energy). It isn’t until we have no power that we realize truly how much our day-to-day life depends on it. But realistically, it is not that much time. That means you only will get a return on a diesel generator an average of 2 days out of the year. With prices within the same range, the scale leans heavily towards installing a battery in nearly all categories.

Do I need solar to have a battery?

Solar energy is not required to install a battery at your home. The key difference is that you cannot “refuel” a battery without sunlight during a grid failure like you can refuel a diesel generator (assuming you have access to fuel). A battery can be charged from grid power, but you are always at the mercy of your utility pricing by going this route. With solar, you can charge and recharge, maintenance-free. There is a common misconception that solar only works in the sunny “hotspots” in the United States. As you can see in the image to the side, there are still enough quality sun hours a day to provide anyone in the United States with enough energy to fully charge a battery. 

Battery Recommendation

LG CHEM Resu 10H

This lithium-ion battery is our first choice for a home energy storage solution because it can be paired with a solar panel system. When paired with a SolarEdge inverter and optimizers, users can track their power consumption, solar production, and battery levels at any time of the day. This battery requires a critical panel load to be installed, with a simultaneous 25A capacity. For the typical American home, this would still allow you to power the essentials to get by during an outage (refrigerator, bathroom, furnace, etc.).

Generator Recommendation

Generac 20kW 6244

This whole house generator has an air-cooled aluminum enclosure along with technology that allows it to safely and efficiently power any household item. A 200A auto transfer switch provides you with the ability to power an entire home, as opposed to only critical loads as a battery would.


To conclude, we believe that the future is bright for solar with energy storage. With costs continuing to decline it is becoming more and more affordable for homeowners to transition to a renewable option. With competitive pricing and no sounds or smells, solar with battery is our unanimous winner.

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