ramblinChet
Well-known member
This report presents the system validation and verification results for my solar power system and battery bank after 30 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 30-day period, the maximum SOC ranged from 64% to 100%, with 18 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 September’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 initial 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 30-day period.
The histogram below illustrates the minimum SOC achieved by the battery bank during each 24-hour cycle. Over the 30-day period, the minimum SOC ranged from 49% to 92%, with 12 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 30-day period was 49%, 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 30 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 over half of the days, with a few days only reaching the Absorption phase. This indicates that the system was fully or nearly fully charged for approximately two-thirds of the time. On September 23–25, rainy conditions limited solar input, while on September 26–28, the system operated primarily under forest canopy, absorbing as much energy as possible. By September 29, the system fully recovered and reached the Float phase.
This data is associated with the chart above - note I changed Absorption from 120 minutes to 60 minutes on 18-Sep-25. 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. There's no sensation to compare with this - suspended animation, a state of bliss...
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 30-day period, the maximum SOC ranged from 64% to 100%, with 18 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 September’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 initial 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 30-day period.
The histogram below illustrates the minimum SOC achieved by the battery bank during each 24-hour cycle. Over the 30-day period, the minimum SOC ranged from 49% to 92%, with 12 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 30-day period was 49%, 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 30 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 over half of the days, with a few days only reaching the Absorption phase. This indicates that the system was fully or nearly fully charged for approximately two-thirds of the time. On September 23–25, rainy conditions limited solar input, while on September 26–28, the system operated primarily under forest canopy, absorbing as much energy as possible. By September 29, the system fully recovered and reached the Float phase.
This data is associated with the chart above - note I changed Absorption from 120 minutes to 60 minutes on 18-Sep-25. 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. There's no sensation to compare with this - suspended animation, a state of bliss...
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