Battery backup planning
Backup Load Voltage Guide for Solar Batteries
Battery backup is not only a kWh question. The loads you choose can depend on voltage, startup surge, dedicated circuits, transfer equipment, and whether the appliance belongs on a critical-load panel.
Updated 2026-07-01
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Panels, cost, savings
Voltage changes design
Many everyday loads are 120V. Larger equipment may need 240V support, a dedicated circuit, or a different backup strategy.
Surge matters
Motors and compressors can draw more power at startup than their running watts suggest, which can affect inverter sizing.
Circuits must be verified
A backup-load panel, transfer switch, or whole-home backup design should be confirmed by the installer and electrician.
Short answer
Start by listing what you actually need during an outage: refrigerator, internet, lights, garage door, medical equipment, sump pump, well pump, HVAC, or a few outlets. Then separate those loads by voltage, circuit type, startup surge, and whether they are truly critical. A battery quote that only says "backs up the home" is not specific enough for planning.
Common 120V backup loads
- Refrigerator or freezer, depending on startup surge.
- Internet modem, router, laptop chargers, and selected outlets.
- Lights, garage door opener, and small medical devices.
- Some sump pumps or small pumps, after surge is checked.
Loads that need extra scrutiny
- Central HVAC, well pumps, pool pumps, dryers, ovens, and EV chargers.
- Hardwired equipment that cannot be treated like a plug-in appliance.
- Any motor load with high startup surge or unclear nameplate data.
- Portable or imported equipment with non-U.S. plug or voltage requirements.
When PlugVoltage is useful
If you are checking a portable device, travel appliance, imported charger, or anything with a non-U.S. plug, use a plug type and voltage guide before treating it as a normal battery backup load. That does not replace electrical design, but it can help you catch plug, voltage, and adapter questions before they turn into quote assumptions.
Questions to ask before signing a battery quote
- Which exact circuits will be backed up?
- Does the inverter support 120V only or 120V/240V backup?
- Which loads are excluded because of surge, voltage, or circuit design?
- Is this a critical-load panel, whole-home backup, or manual transfer setup?
- What is the continuous output and surge output limit?
- Who verifies the circuit list, permit requirements, and safe installation?
What to do next
Use this voltage checklist before comparing solar-plus-battery quotes. Then estimate battery payback separately from backup resilience.