How Much Battery Backup Do I Need?

Project Solar offers Enphase Batteries in 10.08kWh and 3.36kWh increments. 

If you plan to include backup in your home solar system, you may be wondering how many batteries to purchase. This article will briefly explain battery capacity and show you how you can use Enphase's online estimator to quickly size a battery system that will suit your needs.


How Much Does a Solar Battery Back Up?

Project Solar offers batteries in 10.08 kWh and 3.36kWh (may be unavailable in some areas) sizes. Each 3.36kWh battery can power 5.3 amps, and each 10.08kWh battery can power 15.9 amps. 10.08kWh batteries will commonly be connected to a 15-20A breaker. While some customers do opt for full-home backup, a single battery (of either size) usually can't back up an entire home for an extended period.


Instead, batteries can be configured to back up essential circuits (lights, refrigerators, Wi-Fi routers, etc.), or multiple batteries may be purchased to provide more capacity. Enphase battery systems are expandable: you can add multiple batteries to your system or add more batteries down the road as needed.


It takes some understanding of electricity and a little math to size a battery system perfectly (our engineering team will help), but you can get a good idea of what you need by using Enphase's estimator tool. Check out the section below to learn how to use this tool.


The Enphase Estimator

Enphase offers a helpful tool--the Enphase Estimator--to help you determine how much storage would be required for your specific circumstances. 

To use this resource, simply follow these steps:

  1. Enter your address or zip code, as well as your average electricity bill.
    If you are a new homeowner without electric bill information, you can provide a square footage number instead:

  2. Next, select the "Battery" option and adjust your desired backup time:
    You can also add a pool pump, air conditioner, or Electric Vehicle. Once you've updated the appropriate fields, select "Show My System Estimate".

  3. Next, the Estimator will provide a recommendation based on the information you entered:
    You can download your system summary, or select "Additional Configuration" if you'd like to refine your estimate further.

  4. When refining your estimate, Enphase will give you the option to add many different appliances to your system. If you'd like to backup an appliance that isn't listed, you can add it manually:
    When you add appliances, your system summary will update with further storage as needed.

Once you're done sizing your battery storage system, contact your Onboarding Specialist to add it to your Project Solar design and contract.

To learn more about batteries, check out the following articles:

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