battery backup
How to think about critical loads, outage duration, battery sizing, time-of-use rates, and solar-plus-storage proposals.
Last reviewed: May 25, 2026
Battery backup should start with critical loads such as refrigeration, lighting, medical equipment, internet equipment, well pumps, garage access, and selected outlets instead of assuming whole-home backup by default. A quote should separate convenience loads from safety-critical loads because whole-home backup can require more equipment, more battery capacity, and different electrical work.
A battery may be configured for outage backup, self-consumption, demand management, or time-of-use savings. The same battery capacity can produce different value depending on utility rules, seasonal usage, and how the system is programmed. Ask whether the proposal assumes daily cycling, reserve capacity for outages, or both.
Battery proposals should identify usable capacity, inverter compatibility, critical-load panel needs, fire-clearance requirements, warranty terms, monitoring, and whether solar can recharge the battery during grid outages. They should also state what is not backed up, how long backup is modeled to last, and whether local permitting or utility rules affect the design.
This guide is source-aware, but it is not tax, legal, engineering, or financial advice. Confirm current program rules, utility requirements, product terms, and property-specific conditions before making a decision.
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