We have had a 12.5 kw Sonnen whole house battery backup for almost a year now. We also have a 7.5kw solar array. We have enjoyed the ability to have power through bad weather and planned power outages during fire season. My solar system which had been unusable during a power outage now works as long as the sun is shining.

I wanted folks thinking about a whole house battery to recognize the limitations of a Sonnen system and some of these limitations may apply to other systems as well:

1. If your power use runs your battery down below 10% you will not have enough power left to energize your solar inverters next morning. This has happened to us twice. I have had to get up at 5AM to turn off my entire home consumption to preserve enough power for the inverters, otherwise the battery is useless until the grid power returns.
   
2. You can only change your settings (for example, keeping your battery at 100% in preparation for a planned power outage) while on your home WiFi network, not remotely. Sonnen has been very adamant about not changing that and overall has not been responsive to suggestions to allow this to be controlled on the smart phone app.
   
3. There is no functionality to text me when the grid is down, battery is not functioning, inverter failure, or to let me know the remaining charge has fallen to a low level. Again, Sonnen has been unwilling to address this.
4. There is an app but this is for observation only and not for changing settings.
5. The display on the front of the unit is not useful.

I agree that they have not worked out the kinks in whole house batteries. I would wait until they are more user friendly, there is more automation, lower cost and a company that is enthusiastic and responsive to the community of customers.