Future-proofing battery storage systems

Residential sonnenBatterie Solar Backup installed in Sonoma County


In the energy field, we are seeing a major change in homeowner’s choice of fuel source. They are switching from gas appliances and vehicles to electric ones. Some of their reasons are:

  • Electric appliances have become more efficient then their gas counterparts
  • Environmental concerns about methane release (Some say that while natural gas burns clean, the full cycle of natural gas, including obtaining it, can be worse for the environment than burning coal.)
  • Internal home air quality from the fumes of burned and unburned natural gas
  • Concerns of gas appliances being turned off in a fire or earthquake
  • The cost of fossil fuel continues to increase and is not predictable
  • More of their usage can be powered by the renewable energy of the sun

Design Considerations

If you are considering fuel switching, it is important to consider how to backup these future loads when designing your solar and storage system. One of the biggest issues facing electric appliances with motors is the wattage surge that occurs at startup. For example, a well pump may run at 1,000 watts, but it will surge to 5,500 watts when it first starts. One reason we sell Sonnen storage is because it:

  • can surge for 1 ms (millisecond) to 22,000 watts
  • can surge for 100 ms to 15,554 watts
  • can surge for 5 seconds for 11,000 watts
  • has running power of 8,000 watts
  • has battery storage from 10 kWh to 20 kWh, depending on model and need

Roof-mounted solar panels on house

Sonnen offers one of the widest power ranges for storage systems in the industry. In a blackout, when a homeowner with a Sonnen system takes a hot shower using their electric water heater and the refrigerator kicks on, they will not be doused in cold water because the Sonnen can cover this surge of over 9,000 watts

One of my favorite analogies for understanding the importance of surge, run rate, and kWh available for storage, is a car. The fuel tank in the car, like the kWh of the battery, gives us the fuel we need to run the engine. The engine of the car not only has to have the power to get us to cruising speed, but also the power to pass on a hill when needed.  While most storage systems have the inverter power to cruise, they lack the surge power to start large motors (passing power).

Design Tips

Moving to an electric appliance can make sense, especially when combined with solar and storage, as long as you have thought out the process. Here are a few tips:

  • Many folks are switching to induction stoves.  And while induction stoves usually are not backed up because of their high energy draw, a single induction hot plate works great in a pinch. It uses significantly less energy and is thus easier to backup.
  • Another trend is a hot water heat pump or electric water heater. Since these devices surge at up to 6,000 watts, make sure your backup device can handle these if you want a warm shower when the power is out.
  • Heating and cooling designs often incorporate a mini-split heat pump. Mini-splits can heat and cool your home. We added one to our rental and will be adding another to our main house. They are very efficient, and because of their low wattage usage, can be added to backup systems for heating and cooling.
  • New homes and many major remodels require fire suppression systems, don’t forget the fire suppression pump on your back-up.

Atkinson sonnen solar backup batterie


When selecting a storage system for your home, it is important to consider your needs, not just for today but also for your future. A good installation vendor will work with you to properly size your system and select the appliances and devices you desire to be backed up in an outage.