What we can do — and what we can’t
We install Tesla Powerwall 3, Enphase IQ Batteries, and SigEnergy systems, and we can add one of those to many existing solar systems, including ones we didn’t install. What we don’t do is service, repair, or take over another company’s solar system. If your existing panels or inverter need work, that stays with the original installer or the manufacturer.
We also can’t promise what adding a battery does to the warranty on equipment someone else installed. Some installers and manufacturers are fine with a third-party battery; some have conditions. Check your existing warranty paperwork, and ask the original installer if they’re still in business.
What decides compatibility
The existing inverter is the first thing we look at. Microinverter systems, string inverters, and optimizer systems each connect to batteries differently, and some older inverters don’t play well with backup operation. An Enphase microinverter system is a natural fit for Enphase batteries; Powerwall 3 and SigEnergy can be AC-coupled to many other systems, within limits we check against your equipment.
Next is your electrical panel: a battery needs space and, for backup, a way to isolate the house or a critical-loads panel. Then the paperwork: adding storage requires updating your interconnection with the utility. If your solar is leased or under a PPA, you’ll need the leasing company’s permission before anyone touches the electrical side.
Why people add batteries now
Two reasons dominate in Colorado. On Xcel’s time-of-use plan, a battery covers the 5–9 pm weekday on-peak window, priced at about 2.7 times off-peak. And in areas that have seen wildfire shutoffs, a battery keeps essentials running — something your existing grid-tied solar can’t do on its own.
As of September 2026, Colorado offers a 10% state income-tax credit on battery purchases for tax years through 2026, batteries are exempt from state sales tax, and batteries owned through a lease keep federal §48E eligibility through 2033. Fort Collins Utilities pays a solar-paired battery rebate of $300 per kWh (6 kWh minimum, up to $6,000). Other utility programs exist and change; verify current terms.
Local rules worth knowing
Adding a battery isn’t the same as adding panels. In Longmont, systems new or expanded after January 1, 2025 move to value-of-solar export credits, while older systems keep retail credits through January 2040 — so if you’re in Longmont with a pre-2025 system, ask before adding panels alongside the battery. Other utilities have their own rules on modifying an interconnected system.
What to do next
- 1Find your inverter make and model — it’s on the inverter label or in your monitoring app.
- 2Pull your original contract to see whether the system is owned, leased, or a PPA, and what the warranty says about modifications.
- 3If it’s leased or a PPA, contact the leasing company about adding storage before anything else.
- 4Take a photo of your main electrical panel with the door open.
- 5Run the blackout-runtime or peak-shift calculator depending on whether backup or bills is your main goal.
- 6Schedule a site assessment with us; we’ll confirm compatibility before quoting.
FAQ
Questions we hear
Can you add a Powerwall to solar another company installed?
Often, yes. Powerwall 3 can be AC-coupled to many existing systems. We check the existing inverter and panel on site first. We won’t service or modify the existing solar itself.
Will adding a battery void my existing solar warranty?
It depends on the original installer’s and manufacturer’s terms. We can’t promise the outcome. Read your warranty documents and ask the original installer before proceeding.
My solar is leased. Can I still add a battery?
Possibly, with the leasing company’s approval. Contact them first — adding equipment to a leased system without permission can breach the agreement.
Do I need a new interconnection agreement to add a battery?
Generally you need to notify or apply to your utility when adding storage to an interconnected system. We handle that paperwork as part of the install.
Is adding a battery cheaper than buying solar and battery together?
The battery itself costs about the same either way — around $19k for a first Powerwall 3, about $17k for 10 kWh of Enphase, or about $15.5k for 9 kWh of SigEnergy. You avoid paying for new panels, but compatibility work on an older system can add cost.