What are my Battery Options with Project Solar?


Though they are pretty new to residential solar systems, solar batteries have recently become much more popular - particularly with the introduction and subsequent marketing of the Tesla Powerwall. Project Solar does not always recommend batteries, but we do offer them.

At Project Solar, we offer the Enphase IQ Batteries in 10.08kWh and 3.36kwh increments (3.36kWh batteries may be unavailable in some areas). They are specifically designed for use with microinverters, and can be controlled through the Enphase App. 

You can check out EnergySage's review of these batteries here.

Included with our battery builds is the Enphase System Controller 2, which enables automatic backup in the event of a grid outage.

We don't always recommend batteries, though.

This article will outline the following:

Battery Downsides

The main issue we have with batteries is cost–they’re expensive.

Adding storage to your system will increase the cost of your project, but not the size of your system–this means that they can increase your price per watt significantly.

Most battery options are also only warrantied for around 10 years, which is less than half of the projected life of your solar system. Enphase’s IQ batteries are warrantied for 10 years or 4,000 cycles, and they offer a 5-year/2,000 cycle extension for an additional charge if desired.

Like other new tech products, residential solar batteries are expected to improve over time–as are their prices and warranties. They will likely be more cost effective in the future.

Battery Upsides

We believe in providing customers with the best ROI possible, and, in some cases, batteries can be a  worthwhile investment.

There are generally two main situations where this is the case:


Backup Power

Homes in areas with frequent and/or extended power outages can benefit from a solar battery. In this instance, the battery functions like a backup generator.

If the grid goes down, the system will start sending any excess power into the battery, which your home will draw energy from until grid power is restored (or until the battery is depleted).


Some power companies charge more for power used during high-traffic times, or during the evening. Others will have less advantageous net metering or solar buyback rates.

With a battery, extra energy that is produced can be captured for later use, rather than sent back into the grid.

Storing excess energy from earlier in the day can also help reduce energy use during usage times that may be more expensive.


Should you fall into one of these categories, batteries may be right for you–otherwise, they may not be as profitable of an investment.

How to Size Your Battery System

Most customers simply decide to install one 10.08kWh battery, but if you are concerned with backing up particular appliances or other specifics, the Enphase Estimator can be helpful.

This resource uses usage data from you to estimate storage, and also takes into account your desired backup time, specific appliances, electric vehicles, etc.

Adding Batteries to Existing Systems

Some homeowners have already installed solar without batteries in the past, and would like to add battery storage to their system now.

Project Solar does not tie-in to existing systems unless they were installed through us. This also means that we do not offer independent battery installs for new customers with existing systems.

Existing systems are not always compatible with the batteries we use, and it can be difficult, expensive, and even impossible to tie into them.

Plus, fiddling with your existing system can affect its warranty.

We recommend contacting the company who initially installed your system, an equipment distributor, and/or a local contractor.

If the system was installed through us, we will most often be able to tie-in and add a battery.

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