Which Battery is Best for Whole Home Battery Backup?

By definition, a whole home backup inverter-charger backs up all the loads in the home. Therefore the battery needs to be able to support not only a high discharge rate but also deliver both high power output to support the startup surge of the inverter and be able to accept high charge current. Almost all inverters in this class are 48V DC input. When the backup batteries are used, they are likely to experience a deep discharge, but they will also spend a significant amount of time in Float. Autonomy needs vary, but often the system will be supported by a generator when long-duration blackouts are expected. Often the battery storage room or closet in the home has a significant impact on the physical size and configuration of the battery system. Temperature is not usually a concern. Access is usually not a concern, but many homeowners would prefer to live without maintenance complications.

NOTE: If combined with solar, the whole home backup system will likely be used to take the home ‘off the grid’ to increase self-consumption, and if allowed, the inverter’s grid sell functionality will be used to lower energy purchase costs. If this is the case, the battery will be cycled regularly and may be often operated in Partial State of Charge situations (PSOC). Monitoring of lifetime battery energy throughput will be of significant value to homeowners and grid management companies.