Inverter-direct, Web-based data monitoring usually uses Cat-5 communications cable (Ethernet cable), connected between the added data logging and communications hardware (mounted internally or externally to the inverter) and an Internet portal and router on your local network. From there, system data is sent to the manufacturer’s Web server. Sometimes this hosting service is free of charge, but make sure you understand what the cost is (now and in the future) before you make your purchasing decision. The costs for the required hardware and Web-hosting fees can be small in comparison to the rest of a larger PV system, but can be overkill for small- to medium-sized residential PV systems.
Here is an overview of each company’s inverter-direct data monitoring options. While we do show prices for some of these data-monitoring solutions, prices and terms will vary depending on the equipment distributor.
Enphase Energy’s microinverter system offers its Envoy communications gateway hardware (MSRP: $495) that facilitates access to system data via the company’s Enlighten Web site. Enphase’s products are unique for a few reasons. No additional cabling is required since communication is sent through each inverter’s AC output to the Envoy via the wall outlet it is plugged into. Installing the data-monitoring system is as simple as plugging the Envoy into any standard wall outlet and connecting its cable to the household’s Internet router.
Data (instantaneous watts plus daily, monthly, and cumulative kWh) is collected for each PV module/inverter pair. On the Enlighten Web site, this information is presented numerically, and dynamically—with daily graphics representing how much power each module is producing in real-time. This allows owners to easily identify underperforming modules. The Web site also allows users to view historical performance data and will generate energy production reports. While access to the Enlighten Web site may be free initially (typically for 90 days), extending the subscription costs $2 per microinverter, per year. The Envoy can also display data over a local network without the official Enlighten Web site.
Fronius USA offers several data-monitoring options for onsite data logging and monitoring, or Internet-based data monitoring. Each option requires a COM card (MSRP: $143) and one data logger ($445 for the data logger EASY card for onsite monitoring for one inverter; $1,350 for the Datalogger Web for online monitoring of up to 100 inverters). Fronius also offers an internal sensor interface card ($689) or an external sensor box ($737). Both can collect data from irradiance sensors, module and ambient air temperature sensors, and wind-speed sensors (purchased separately).
Online data access is provided via Fronius’ free SolarWeb portal, where users can view graphs of real-time power, and daily and lifetime kWh, along with sensor data (if installed). Archives of past data are also available.
Kaco Solar currently offers onsite and Internet-based data monitoring via proLOG hardware (MSRP: $855 for the proLOG M with LED display and one sensor port; $1,375 for the proLOG XL, with an LCD display and four sensor ports). Optional irradiation, temperature, and current sensors are available. Each data logger can monitor up to 32 Kaco inverters. Online monitoring is accessed via Kaco’s Blueplanet server ($60 for five years) that displays information such as instantaneous watts and daily, monthly, and yearly kWh.