Frequently asked questions

Every watt your home uses — from the battery, your solar panels, or CFE — passes through the hybrid inverter before it reaches your outlets. The inverter is the heart of the system.

When you’re running on battery or solar, the inverter generates a clean, pure sine wave from scratch — the stable, ideal form of power your electronics are designed for.

When power comes from CFE, the inverter passes it through while monitoring it 60 times per second, confirming the voltage stays within safe limits — never spiking above or dropping below the threshold for safe operation.

The result: your home always receives clean, conditioned power, and your sensitive equipment is protected from the voltage spikes and dirty power that often come directly from the grid.

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 when running on stored energy. 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.

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.

Why this matters for your CFE bill: Mexico’s residential electricity pricing is tiered — the rate jumps dramatically once you exceed the lower consumption thresholds. If you have solar, the system’s primary goal is to reduce the kWh you purchase from CFE, keeping you in the lower-cost tiers and significantly reducing your bill over time.

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

Because all power still passes through the inverter, the switch to CFE is seamless — and your equipment stays protected from the voltage spikes and dirty power that often come directly from the grid.

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. With the optional automatic transfer switch (ATS), your generator integrates directly with the system. 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.

This is one reason we recommend starting with the larger battery capacity (16 kWh). More storage means greater resilience during extended outages.

Yes, the system is fully modular. You can start with a 5 kWh 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 16 kWh 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.

It depends on how the panels are mounted:

• Pergola, elevated, or angled installations: Bifacial panels are ideal. Raised or tilted off the surface, 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.
• Flat roof installations: Either bifacial or monofacial (single-sided) panels work well. Mounted flat against the surface, bifacial panels capture little to no reflected light, so they offer no additional benefit over monofacial — same wattage output, same price.

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

Installation is quoted after a site visit — because every home is different. Once we’ve seen your electrical panel, the mounting location, and how your home is wired, we can price the work accurately based on the time and complexity of the job.

Factors that affect the installation quote include:

• Circuit-separation subpanels for specific load management
• Extended cable runs over long distances
• Special structural mounting requirements
• Configurations that fall outside standard residential parameters
• Accessories such as an automatic transfer switch (ATS) for a generator or multiple-meter connection
• Connecting existing solar panels

Your full installation cost is laid out clearly in your proposal after the site visit — complete transparency, without surprises.

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 3–4× 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
• With solar panels: powering your home directly from the panels during daylight hours and storing the surplus in the battery for use at night
• Only drawing from CFE when the battery is low and no other source (solar or generator) is available

Firefly with solar panels delivers the biggest bill reduction. Beyond powering your home and charging the battery, surplus daytime generation is fed back to the grid under Mexico’s net metering program (medición neta), earning kWh credits that offset what you draw at night. In effect, the sunlight you capture by day pays for the power you use after dark.

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.

Solar panel warranty terms vary by manufacturer. Your proposal will list the exact warranty figures for the panels specified in your system.