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.

As part of a Full Service Installation, we offer the Enphase IQ 5P Batteries or the Tesla Powerwall 3. For DIY projects, we currently only offer the Enphase IQ 5P. 

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

Without a System Controller, Enphase batteries won't be able to disconnect from the grid, and your system will shut down during outages - called "consumption offset configuration", where your battery will still work to offset your home's electricity consumption (only available with select utility companies).

Tesla Powerwalls will also include a System Controller, and are only available for backup configuration. 

Though we do offer them, we don't always recommend batteries. 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.

Our battery pricing is as follows:



DIY Pricing (Before Any Incentives)

Full-Service Install Pricing (Before Any Incentives

First Enphase IQ 5P Battery + 1 System Controller (Backup Configuration)

$6,500 $8,500

Each Additional IQ 5P Battery (Backup Configuration)

$3,500 $5,500

First Enphase IQ 5P Battery (Consumption Offset Configuration)*

$3,500 $4,500

Each Additional IQ 5P Battery (Consumption Offset Configuration)*

$2,500 $4,500

First Tesla Powerwall 3

N/A $13,000

Each Additional Tesla Powerwall 3

N/A $9,500

*Only available with select utility companies. Please contact a representative to confirm. 

Most battery options are also only warrantied for around 10 years, which is less than half of the
projected life of your solar system.

Tesla follows this trend with a 10 year limited warranty. Enphase’s IQ 5P batteries have a longer warranty: 15 years or 6,000 cycles.

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.

If you opt for an Enphase consumption battery configuration, your battery will only function for this feature, and won't be able to disconnect from the grid during outages (as a System Controller is not included). 


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 around 5-10kWh of batteries, but if you are concerned with specifics, our Customer Experience Team can help you size a battery system based on your usage patterns and the appliances you wish to back up. The Enphase Estimator can also be a helpful resource in sizing Enphase battery systems. 

Affordable Backup Alternatives - Power Bank


The main hangup on batteries is simply their cost--they are expensive, even with our low pricing. To combat this and provide a more accessible option, Project Solar offers the Power Bank Solar Battery Kit.

This kit is also a great option for Full Service Install customers who don't have Enphase batteries available in their area. 

The Power Bank is a portable battery that is used separately from your solar system. It can be taken with you wherever you go, or tied into your home's essential loads with a subpanel. 

This option is not yet available as part of a solar install, so you will need to purchase it separately from our website.

To charge the Power Bank with solar energy, customers with a solar system can plug it in to a standard AC outlet during high-production times to capture energy and store it for later use. If you don't have a home solar system, we offer optional portable solar panels.

The Power Bank can even be charged from your car in a pinch. 

Project Solar offers the Power Bank in two models: 600 & 2000. There are also Expansion Packs available for those wishing to increase their Power Bank 2000's capacity (the Power Bank 600 is not expandable). 

Though it cannot provide the same automatic backup and smart-home capabilities as the Enphase battery, the Power Bank is a much less expensive option. With two Expansion Packs, the Power Bank 2000 is able to offer 8.064kWh of storage for less than $5,000. 

To learn more about our Power Bank products, check out our Information Guide

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. Alternatively, you could purchase a battery that doesn't have to integrate directly with your solar system, like our Power Bank Home Backup Kit.

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


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