Solar panels may be the face of your system, but the energy they produce needs to be managed, converted, and safely delivered to your building. That’s where inverters and the Balance of System (BOS) come in. Together, they make up the “infrastructure” layer of your solar installation – the wiring, brains, and support systems behind the scenes.
Inverters: Converting Solar Power to Usable Power
Inverters are responsible for turning the direct current (DC) electricity produced by solar panels into alternating current (AC) electricity, which powers most commercial buildings. Without an inverter, your system can’t interact with your facility or the grid.
Types of Inverters:
- String Inverters (most common): One or more units connect to series “strings” of panels
- Microinverters / Optimizers: More common in residential or specialty use cases where shade affects individual modules
- Central Inverters: Used in very large utility-scale projects
Inverter Types: String Inverters (Most Common in Commercial Systems) #
String inverters are connected to multiple strings of solar panels – each string being a series of panels wired together. These are cost-effective, easy to maintain, and the standard choice for most medium-to-large commercial systems.
Pros:
- Lower cost per watt
- Centralized monitoring and maintenance
- Proven, reliable technology
Cons:
- Performance of each string depends on the worst-performing panel (if one is shaded or faulty, output can drop)
- Requires uniform string lengths and exposure
Ideal for: Large, unshaded rooftops or ground mount systems with uniform layout
Inverter Types: Microinverters #
Microinverters are installed behind each individual panel, converting DC to AC at the module level. While more common in non-commercial/non-utility systems, they may be used in small commercial arrays or highly complex roof layouts.
Pros:
- Each panel operates independently – maximizing output when shading or mismatch occurs
- Panel-level monitoring for diagnostics
- No centralized inverter needed
Cons:
- Higher upfront cost
- More points of failure
- Maintenance can be more involved due to rooftop placement
Ideal for: Small commercial buildings with shade, multiple roof planes, or architectural complexity
Inverter Types: Power Optimizers (Hybrid Option) #
Often used with string inverters, power optimizers are installed at each panel to improve efficiency. They condition DC power at the module level before sending it to the string inverter.
Pros:
- Mitigates effects of shading or module mismatch
- Panel-level monitoring
- Lower cost than full microinverter setups
Cons:
- Still requires a centralized inverter
- Added complexity vs. traditional string inverter systems
Ideal for: Commercial systems with some shading or performance variability
Inverter Types: Central Inverters (Utility Scale Only) #
Central inverters aggregate power from hundreds or thousands of panels into one large unit. These are rarely used in commercial settings, but are standard for utility-scale solar farms (multi-megawatt).
Pros:
- High efficiency for large-scale applications
- Streamlined O&M at the system level
Cons:
- Not modular – if the inverter goes down, large portions of the system stop producing
- Large physical footprint
Ideal for: Utility-scale solar fields and large power plants
Inverter Comparison Table
| Inverter Type | Installed Location | Panel-Level Optimization? | Cost | Best Use Case |
| String | Near array or in electrical room | No (unless paired with optimizers) | $$ | Most commercial rooftops and ground mounts |
| Microinverter | Behind each panel | Yes | $$$ | Small systems with shading or complex layouts |
| Power Optimizer + String | Behind panel (optimizer) + centralized inverter | Yes | $$ | Moderate-sized systems with partial shading |
| Central | Centralized location | No | $ (per watt, but large scale) | Utility-scale, multi-MW solar farms |
DC/AC Ratio and Inverter Sizing
Every inverter has a power rating in kilowatts (kW AC), just like your solar panels have a rating in kilowatts DC. Designing a system requires pairing these two values together thoughtfully.
A well-designed system typically has a DC/AC ratio between 1.1 and 1.3. That means your panels are capable of generating slightly more power than your inverter can process at a given moment – but that’s a good thing.
Why oversize the system?
- Solar panels rarely operate at full output
- Slight oversizing improves inverter utilization and energy harvest over time
- Clipping (where some energy is “lost” during peak production) is minimal in most designs – typically under 2–5%
Example: A 9 kW DC array paired with a 7.6 kW inverter has a DC/AC ratio of 1.18 – common and efficient.