Start by correcting a common assumption: ordinary grid-tied solar panels do not keep a house powered when the utility grid fails. The U.S. Department of Energy’s rooftop-solar resilience guidance explains that most residential systems lose power with the grid. A retrofit must create a safe, controlled source of electricity inside the home while preventing power from flowing back onto utility lines.
Identify the existing solar equipment
Gather the original plans, permits, warranties, monitoring information, module list, inverter model, service-panel details, and interconnection agreement. The installer should verify whether the inverter can support storage directly or whether the retrofit needs separate power-conversion equipment. “Battery ready” is useful only when the proposal identifies compatible models, required hardware, and warranty effects.
Define what backup actually means
List the circuits you want available during an outage and their running and startup loads. Refrigeration, internet equipment, lighting, medical equipment, a sump pump, and selected outlets create a very different design from central air conditioning or whole-home electric heat. Ask the proposal to show battery energy capacity, inverter output, expected duration, and which loads are excluded.
The Department of Energy’s Solar-Plus-Storage 101 describes storage as a way to use connected solar energy later, including during an outage. Actual duration still depends on available charge, sunlight, weather, equipment limits, and household demand.
Require safe islanding and approved equipment
A backup retrofit needs compatible storage, a backup-capable inverter or equivalent controls, and approved isolation or transfer equipment. Those components create an intentional island for selected home loads and stop electricity from energizing the utility connection. Independence Power & Light’s current net-metering and interconnection requirements call for approved inverter/interconnection equipment and anti-islanding protection.
Ask how solar behaves while the grid is down
Do not assume every battery retrofit lets the existing panels recharge storage during an outage. Ask the designer to explain, in writing, whether the proposed equipment can accept solar production while islanded, how it responds when the battery is full, and how the system restarts after shutdown. The answer depends on the specific inverter, battery, controls, array configuration, and approved design—not simply on having panels and a battery at the same address.
Check permits, interconnection, and the existing agreement
Do not assume a battery can be added after the fact without review. Ask the City and IPL which plan revisions, permits, inspections, disconnects, labeling, or interconnection updates apply to the proposed equipment. Our Independence solar permit and IPL guide explains the broader approval sequence.
Compare retrofit proposals on the same basis
Each proposal should identify the battery and inverter models, usable capacity, continuous and surge output, backed-up circuits, expected runtime assumptions, recharge behavior, installation location, warranty, monitoring, service responsibility, and complete price. If the existing array has performance issues, review monitoring and maintenance first using the Independence solar maintenance guide.
Also ask who supports the combined system after installation. A battery company, the original solar installer, and a retrofit contractor may otherwise point to one another when monitoring or equipment fails. Put responsibility for commissioning, app access, warranty claims, and future service in writing.