Frequently Asked Questions

If you have solar panels, they become the primary power source during the day — powering your home and charging the battery simultaneously. CFE only kicks in automatically when the battery is running low and solar production isn't sufficient (cloudy skies, high demand, or nighttime). The system manages all of this automatically with no manual switching required.

If you don't have solar yet, the battery alone still provides backup power and protects your home from CFE outages and dirty power — and solar panels can be added at any time.

Yes. When the battery reaches its low threshold, the system automatically transfers to grid power (CFE) — no manual action required on your end.

Importantly, all power always passes through the inverter, regardless of the source. Whether you're running on battery, solar, or CFE, the output to your home is always a clean, pure sine wave. This also protects your equipment from the voltage spikes and dirty power that often come directly from CFE.

The switchover is seamless and virtually instantaneous. When CFE goes down, the hybrid inverter detects the outage and automatically transfers your home to battery + solar power within milliseconds — fast enough that most electronics and appliances don't even notice the transition.

During the outage, your home continues running normally on battery and solar. When CFE is restored, the system transfers back automatically.

Yes. Your generator connects through an automatic transfer switch (ATS) that is included as part of the installation. You start it manually, the system detects generator power, and the inverter uses it to keep the house running and charge the battery simultaneously.

One important consideration: the generator will prioritize powering the house first, using surplus capacity to charge the battery. Depending on the generator's output, it may not fully recharge a large battery bank while simultaneously running the whole house — but it significantly extends your runtime during extended outages.

Yes, the system is fully modular. You can start with a 5kWh battery module and add more capacity at any time without changing the inverter or any other equipment. The system supports up to 16 battery units in parallel.

That said, we typically recommend starting with the 16kWh configuration if your situation allows. Whether you have an existing solar array or are starting fresh, more battery capacity means greater resilience during outages — and it's more cost-effective to size correctly upfront than to add modules later.

Equipment	Model / Spec	Key Specifications
Inverter	PowMr — Commercial Grade 12KW Split-Phase Hybrid	120V/240V split-phase, dual MPPT solar trackers, WiFi monitoring, pure sine wave output, >95% efficiency, expandable up to 6 units in parallel
Battery	EVE / CATL LiFePO4 48V — 200A BMS with Active Cell Balancing	High-capacity lithium iron phosphate cells, modular 5kWh–16kWh configurations, 6,000+ cycle lifespan, expandable up to 16 units in parallel
Solar Panels	580W Bifacial Grade A	Monocrystalline N-type cells, 22%+ efficiency, dual-glass construction

It depends on the installation location:

• Open patio cover / pergola with open underside: Bifacial panels are ideal here. They capture reflected light from below in addition to direct sunlight from above — exactly what bifacial technology is designed for. Since there's no cost difference, there's no reason not to take advantage of the extra generation.
• Standard closed roof: Monocrystalline single-sided panels are the right choice. They're optimized for roof-mounted installations and perform excellently on pitched or flat surfaces. Same wattage output, same price.

We assess each installation individually and specify the correct panel type for your configuration.

No — solar panels are not required for the system to work. The battery and inverter alone provide backup power, protect your home from CFE outages, and deliver clean sine wave power regardless of source. Many clients start with battery-only and add solar later.

If you already have solar panels, the hybrid inverter unlocks their full value — storing excess daytime generation for use at night instead of sending it back to the grid unused. If you're thinking about adding solar, the system is already designed to accommodate panels at any time with no additional equipment changes.

Standard installation is included in all Firefly packages — it's part of the price, not a separate line item.

We only charge additional installation fees for more complex configurations, such as:

• Circuit separation subpanels for specific load management
• Extended cable runs over long distances
• Special structural mounting requirements
• Configurations that fall outside standard residential parameters

Automatic transfer switch (ATS) installation for generator integration is included as part of the overall project at no additional charge.

A standard Firefly installation typically takes 1–2 days depending on the scope of the project. This includes mounting the inverter and battery, wiring the system into your electrical panel, and final testing and commissioning.

If solar panels are part of your project, or if you're integrating an existing solar array, allow an additional half to full day. Generator ATS integration and other complex configurations may also add time. We'll give you a clear timeline estimate during your assessment.

CFE's residential tariff (Tarifa 01) uses a tiered pricing structure — the more you consume, the more you pay per kWh. The first small block of consumption is subsidized at low rates, but consumption beyond that jumps to the excedente tier, which can be 3–4x more expensive.

The Firefly system reduces the kWh you buy from CFE by:

• Storing energy in the battery and running your home from it rather than the grid
• If you have solar: powering your home directly from panels during daylight hours and storing the surplus for use at night
• Only drawing from CFE when the battery is low and no other source (solar or generator) is available

The result: your metered CFE consumption drops significantly, pushing you back toward the cheaper tiers — where the savings compound over every billing period.

Yes — if your system includes solar panels, Mexico's net metering program (medición neta) allows surplus solar energy to be exported to the CFE grid in exchange for kWh credits, which can offset future consumption.

With the Firefly hybrid system, the battery stores surplus solar energy first — reducing what you draw from the grid at night. Any generation that exceeds both your immediate loads and battery capacity can then be exported for credits. This maximizes the value of every kWh your panels produce. If you're thinking about adding solar in the future, net metering can be enabled at that time.

Equipment	Warranty	Coverage
Inverter	8 years	Parts, labor, and after-sales support
Battery System	8 years	Parts, labor, and after-sales support
Solar Panels — Materials	25 years	Product and workmanship defects
Solar Panels — Power Output	30 years	Minimum 87.4% output guaranteed at year 30 (vs. 80% industry standard)