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House at dusk with lights on

Overview

Synergy has been selling a lot of solar battery storage lately, and I have realized there are considerable differences between designing for rural properties vs. urban ones. I will be writing another blog for those rural homeowners. It is my goal in writing this to provide a basic description of what a homeowner on city infrastructure services should consider today, and in the future, when selecting a storage system for your home.

For example, quite often urban dwellers tell me that they do not mind if the electricity is turned off since most of their appliances are gas. What they may not realize is that without power to the electric igniters on the furnace, stove, water heater or gas fireplace, they may not work.

Also, when we had the 2017 fires in Northern California, PG&E not only turned off the electricity, but they also turned off the gas.  Not just to the burning areas, but, as a preventative measure, also in the areas surrounding the fires. Another factor is many of our gas lines have safety devices that automatically turn off the gas in an earthquake. Having gas appliances is not necessarily a solution to backup.

Effective backup takes planning. It is important to select an installer that understands not only solar and storage, but also understands how your home appliances work. An installer should take the time to learn about your particular home usage and explain the pros and cons of your current environment. They should be able to discuss ways to increase your security and appliance availability in an outage. A great vendor will also discuss how to “future proof” a battery system to meet your needs, today and in the future.

Design

Okay, so let’s move on to designing storage. Below is a list of devices/appliances an urban dweller may want to backup:

  • Refrigerator
  • Igniter for furnace, water heater, gas dryer and/or stove
  • Computers
  • Garage door
  • Router
  • A few plugs and lights
  • Medical equipment like CPAP machine if needed

sonnenBatterie installed in a residential garage

Most of the storage systems out there that have up to a 5,000-watt inverter can do this. The largest appliance listed is the refrigerator, which takes about 800 watts to operate and may surge to 2,000 watts when the compressor first turns on. (Surge is the amount of energy required by an appliance at start-up, which can be considerably higher than the running usage.) While an urban dweller may get by backing up just the above devices/appliances, it does pretty much max out the power available from the system.

When planning for longer outages, a customer may also want to run:

  • Additional lighting
  • Fire suppression pump
  • A dish washer
  • A washing machine
  • A microwave
  • A 110 plug to charge an electric car

Now we are moving into the range that many of the 5,000-watt inverters systems can no longer support. A dishwasher averages about 1,800 watts, a microwave 1,000 watts, a washer about 1,000 watts, and many homeowners have a second freezer or refrigerator, or other appliances they also wish to have backed up. Any of these additions will probably require designing a larger system.

Solar panels shown alongside of a sonnenBatterie

Summary

Personal choice always factors into these decisions. Some people may be okay hand washing dishes or clothes, even in a long outage. Others may forgo the TV or entertainment. Some may want to operate as close to normal as possible. The important thing is to make sure the system you are purchasing meets your needs and supports the appliances you desire. This is why it is important to work with an installer that takes the time to learn about your needs.