Renogy provides the following ways to help you quickly size a power system:

• Method 1: Do it yourself by learning Sizing Your Solar System: A Comprehensive Guide for Panels, Batteries, Controllers, and Inverters.
• Method 2: Visit Renogy Calculators.
• Method 3: Call our pre-sales hotline at 1(909)2877111 (U.S. Service Hotline) or submit a case. We will have a dedicated team member provide you with the best solutions and advice.

This can be considered in 2 aspects:

1. Maximum PV input allowed by the controller
2. Power requirement to maintain the battery power

It is wise to size your battery bank first based on the minimum required capacity, and accordingly decide how many panels or how much power input is needed.
Note: When adding more solar panels, you need to choose solar panels of the same brand and same specification, otherwise there is a risk of efficiency degradation.

To size a proper battery, you need to identify the loads that you will be utilizing, as well as an estimated duration (hours/day) you will be using the load. Oversizing should be considered due to efficiency losses. For details, see Battery Sizing Guide.

Considering safety issues, Renogy strongly recommends you to add a proper fuse between the charger controller and the battery(ies). Fuse Recommended ≥ Charge Controller Rated Amps × 1.25 (Safety Factor). For detailed instructions on how to size a fuse in a solar power system, refer to Fuses and Wire Gauge.

You can use an inline fuse in between the solar panels and the charge controller, and an ANL fuse in between the battery to the charge controller, and battery to inverter. For detailed instructions on how to size a fuse in a solar power system, refer to Fuses and Wire Gauge.