Can you add a battery to solar you already have?
Usually, yes. If you have a working solar system and want backup power or more use of your own production, a battery can be retrofitted. Here is what the process looks like.
Yes — in most cases
Both Tesla Powerwall and Enphase IQ Battery can be added to existing systems. The right choice depends on what's already on your roof — especially the inverter.
What we check first
- Your inverter type. Enphase batteries pair naturally with Enphase microinverter systems. Tesla Powerwall 3 has a built-in inverter and can also be added to existing solar; how it connects depends on your current equipment.
- Panel and meter. We check whether your panel has room, and whether a meter collar can give you whole-home backup without an upgrade.
- Which loads you want backed up. Essentials only, extended, or whole-home — see the backup tiers.
- Your utility agreement. A battery on an existing system requires paperwork with your utility. We prepare and submit it.
What the installation involves
Site assessment
We look at the existing system, panel and meter and decide how to wire the battery.
Permit and utility approval
We submit the permit and the utility paperwork for storage.
Installation and commissioning
Our licensed crew mounts and connects the battery, then tests backup and monitoring.
Is it worth it?
It depends on what you want. A battery is mainly for backup power and for using more of your own solar in the evening. Under California's newer net billing rules, exported power is credited at a lower rate than before, which raises the value of storing it; read NEM 3.0 and home batteries for how that works.
A note on adding solar panels instead
If you're on the older net metering program, changing your system size can affect which rules apply to it. Small changes may be allowed; larger ones can move the whole system to the new tariff. Confirm with your utility, or ask us, before you add panels.
Common questions
Do I need a new inverter to add a battery?
Not always. It depends on your current inverter and which battery you choose. We tell you exactly what's needed after the site assessment.
Will adding a battery change my utility agreement?
A battery retrofit requires storage paperwork with your utility. How it interacts with your existing program depends on the details — we confirm this for you before you commit.
Can the battery power my whole house?
It can with enough units and the right configuration. See the backup tiers on the battery storage guide.
Keep reading
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