Compatibility before purchase
Installed equipment, software, interconnection, and manufacturer requirements are checked before an add-on is proposed.
Existing-system storage expansion
Battery Add-Ons
Expand storage capacity or add compatible equipment to an existing energy system.
- Best fit
- an existing solar or battery system
- Service area
- Coachella Valley and surrounding desert communities
Direct answer
What is a battery add-on?
A battery add-on expands storage or backup capability on an existing solar or battery system. The project begins with an inspection because the installed inverter, controller, service equipment, permits, software, warranties, and available space determine which additions are technically supported.
Service overview
Expansion starts with compatibility.
Existing systems carry decisions made during their original design: inverter type, bus and breaker sizing, communication architecture, transfer equipment, firmware, interconnection method, equipment clearances, and warranty conditions. Those details have to be understood before new storage is selected.
We document what is installed, confirm the owner's capacity or backup goal, and determine whether the right path is adding matching batteries, using supported expansion hardware, integrating a compatible AC-coupled system, or redesigning part of the existing electrical scope.
Designed outcomes
What the design work should clarify.
Capacity with a reason
The expansion target is connected to backup duration, everyday energy use, or new property loads.
A code-aware upgrade
Working clearances, service calculations, disconnects, labeling, and current permitting requirements are reviewed.
Recommissioned as one system
The expanded configuration is tested so controls, charging, backup, and monitoring work together as intended.
Design inputs
What we evaluate before equipment is selected.
- Manufacturer, model, age, firmware, and warranty status
- Existing battery, inverter, controller, and transfer architecture
- Available service, panel, bus, breaker, and conductor capacity
- Permitted plans and the as-built equipment configuration
- Physical space, clearances, conduit paths, and environmental exposure
- New loads, runtime goals, and the reason for adding capacity
Project path
- 01
Existing-system inspection
We document model numbers, electrical connections, equipment condition, software access, available plans, and the installed operating configuration.
- 02
Compatibility and capacity review
Manufacturer support, electrical limits, physical space, warranty considerations, code requirements, and the owner's expansion goal are evaluated.
- 03
Expansion design and permitting
The supported add-on path is translated into equipment, electrical work, updated documentation, approvals, and installation sequencing.
- 04
Installation and recommissioning
New equipment is integrated, firmware or controls are configured as supported, and the expanded system is tested under its intended operating modes.
Questions homeowners ask
Answers about Battery Add-Ons.
Can any battery be added to an existing solar system?
No. Compatibility depends on the existing inverter, electrical architecture, communications, transfer equipment, manufacturer support, utility requirements, and code. Some systems support multiple expansion paths; others are limited.
Can another FranklinWH battery be added to an existing FranklinWH system?
Supported FranklinWH configurations can allow additional battery capacity, but the installed aGate, battery generation, firmware, electrical design, clearances, and current manufacturer requirements must be confirmed before expansion.
Does adding a battery require a new permit?
Battery expansions commonly require permit and plan updates, and they may affect utility or fire-authority documentation. The exact approval path depends on the jurisdiction and the scope of electrical work.
Will a battery add-on increase backup runtime?
More usable storage can increase runtime when the expanded system and electrical design support it. Actual runtime still depends on active loads, power limits, charging conditions, and the operating reserve configured for the system.
What information helps with an add-on review?
Photos of the installed equipment and labels, original plans, permit records, utility documents, monitoring screenshots, model numbers, warranty information, and a description of the desired outcome can make the first review more productive.
Next step
Inspect first. Expand with confidence.
Send us the installed equipment, available plans, and the capacity or backup outcome you want. We will identify the supported expansion path.