Solar Assessment Guide

OVERVIEW

Solar-powered systems are designed with a built-in level of battery autonomy, balancing cost, physical size, and operational runtime. Even with proper sizing, all systems have a finite reserve that will deplete during prolonged periods of insufficient sunlight.

There is a fundamental limitation: if there is no sun, there is no power. This is most acute during winter months, when shorter days and frequent cloud cover reduce solar availability.

This guide provides a standardized procedure for assessing system performance when solar production declines or the battery reports a low state of charge.

ASSESSMENT PROCEDURE

Step 1: Check Current Weather Conditions

Before performing technical diagnostics, verify site-level weather patterns.

• Use the following satellite visualization tool for real-time and historical imagery:

https://zoom.earth/maps/satellite/#view=27.9959,-83.283,7z

• Review the last 24 hours using the playback feature.

Significant cloud cover or overcast conditions typically correlate with reduced solar production

Step 2: Review Historical Cloud-Cover Data

Evaluate cloud conditions for the past several days to determine if weather patterns explain the reduced solar yield.

1. Visit https://weatherspark.com/ 
2. Enter the closest city or airport to the deployment site.
3. Scroll to the Cloud Cover section.
4. Examine the hourly cloud-cover chart.
   • Heavy gray shading indicates limited solar availability.
     • Extended gray periods directly correspond to low battery SoC or offline conditions

Note: Peak solar production generally occurs between 10:00 AM and 4:00 PM, with shorter windows during winter.

Step 3: Examine Solar Production via Victron VRM

Use VRM tools to compare forecasted solar irradiance against actual system performance.

1. Navigate to the site in Victron VRM.
2. Open Advanced view.
3. Enable the Solar Irradiance chart.
   • This chart displays forecasted versus actual solar production.
   • When actual production closely follows the forecast curve, the system is performing as expected.
   • Significant deviations may indicate a hardware or system configuration issue.

Note: This feature requires the site’s location to be properly set in VRM.

REFERENCE PROCEDURES

Reference 1: Enabling the Solar Irradiance Widget in VRM

1. Open the site in VRM and Select Advanced view.
2. Click the Filter button (top-right).
3. Under Gateway, enable Solar Irradiance.
4. Close the filter menu; the widget will now display.

Reference 2: Setting the Site Location in VRM

1. Navigate to the site in VRM.
2. Select Settings.
3. Click Location.
4. Enter the correct site coordinates or address.
5. Click Save.

Note: This process provides a preliminary assessment and should be completed before beginning deeper system diagnostics.