ramblinChet
Well-known member
Solar System Monthly Validation Report – October 2025
This report presents the system validation and verification results for my solar power system and battery bank after 61 days of off-grid travel. The sole power source consisted of two 250-watt solar panels (Rich Solar) connected to a solar charge controller (SmartSolar MPPT 100/30) and a 200 Ah battery bank (two LiTime 12V 100Ah Group 24 Deep Cycle LiFePO4 batteries). Neither the AC-DC charger (Blue Smart IP22 Charger 12V-30A) nor the DC-DC charger (Orion XS 12/12-50A) was used during this period. The objective was to evaluate the adequacy of the solar system and battery bank capacity to support off-grid travel demands.
System validation and verification for a vehicle’s solar-based electrical system involves confirming that the setup meets design specifications and performs reliably under anticipated operating conditions. Validation ensures the system addresses the intended purpose (e.g., providing consistent power for off-grid requirements), while verification confirms proper integration and functionality of components. This process is critical for my setup, where approximately 65% of operation occurs under forest canopy (reducing solar input) and 35% in semi-open areas with partial sunlight, enabling early identification of inefficiencies.
The histogram below illustrates the maximum state-of-charge (SOC) achieved by the battery bank during each 24-hour cycle. Over the most recent 31-day period, the maximum SOC ranged from 69% to 100%, with 24 days recording values between 96% and 100%. Although I did not log the specific times when SOC reached 100%, this value was frequently attained around midday. These results indicate that the system has sufficient solar capacity for most of October’s operating conditions. It will be valuable to assess performance during December and January, when solar input is typically lower. Overall, I am satisfied with these findings, as the system exceeded the design goal of providing sufficient power for seven days using solar energy alone, successfully delivering power for the entire 61-day period.
The histogram below illustrates the minimum SOC achieved by the battery bank during each 24-hour cycle. Over the most recent 31-day period, the minimum SOC ranged from 50% to 93%, with 22 days recording values between 79% and 89%. The minimum SOC was typically reached early in the morning, just before sunrise. During the system design, my goal was to ensure the SOC rarely dropped to 25%. The fact that the lowest recorded SOC over the 31-day period was 50%, with all other values higher, demonstrates the system’s robust performance.
The screenshot below, captured from the Victron Energy solar charge controller, displays the energy collected by the system over the past 31 days. The white portion of each column represents the percentage of time spent in Bulk charge mode, while light blue indicates the Absorption phase and medium blue denotes the Float phase. The data shows that the system reached the Float phase on well over half of the days. This indicates that the system was fully or nearly fully charged for approximately two-thirds of the time. On October 20–22 and 30-31, rainy conditions limited solar input, while on October 23-24 the system quickly recovered pulling in as much as 1.08kWh on a single day.
This data is associated with the chart above. I attempted to attach the CSV file to this post for further review but the uploaded file does not have an allowed extension.
I will periodically measure system performance and publish updates similar to this report. Evaluating the system’s behavior over the coming years will provide valuable insights into its long-term performance and alignment with design expectations.
Here are links to all previous reports:
2025: September