Solar + storage inverter selection: inverter stacking vs. high voltage inverters

commerial solar storage simpliphi project

Scaling an energy storage system requires stacking both energy (batteries) and power (inverters).
Batteries that were designed to be modular can typically be stacked without limitation. However, inverter stacking presents more challenges. The question installers must answer is at what point does it make sense to jump from a multi-inverter stack of 48V inverters to a higher voltage inverter option.

Regardless of the energy storage demand, the power requirement of a project’s load profile is the most important factor when deciding whether inverter stacking or a high voltage inverter option makes sense for a project.

When considering a standard 48V battery-based inverter, stacking is limited to smaller outputs. In fact, most of the largest allowable 48V battery-based inverter stacks cap out at approximately 60 kW. That 60 kW is usually more than enough power to cover residential and even some small commercial systems. For systems larger than 60 kW, making the leap to a high voltage inverter is most often the best choice in order to achieve higher power output and cover larger loads, such as those seen in most commercial and industrial projects.

When deciding whether to stack 48V inverters or choose a higher voltage inverter, be sure to also consider the AC power demands of the project.

48V inverters are ideal for residential projects that consist of 120/240V AC loads, and high voltage inverters are best suited for commercial and industrial projects with 3-Phase 480V AC Power requirements. Choosing a high voltage inverter designed for a greater power output avoids expensive and long installation practices with extra equipment such as transformers and cabling.

Choosing the optimal inverter for the power demands of a given project ensures a less costly installation process and safer, more efficient energy storage system operation for the long term.

This post and the entire 12 Days of Storage was contributed by SimpliPhi.

— Solar Builder magazine

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