NatLabRockies / NatLabRockies/SAM

PVWatts single year to lifetime outputs

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bug
Dominant language
C++
Stars
486
Forks
219
Avg merge
10h 10m
Merged PRs (30d)
2

Description

Describe the bug

Some PVWatts outputs in SAM 2026.7.3 are different from SAM 2025.4.16, possibly due to change from single year to lifetime simulations.

To Reproduce
  1. Create a default PVWatts / Single Owner case in SAM 2025.4.16.
  2. Run a simulation and note annual output and NPV in metrics table, and note AC inverter output power in hourly data outputs.
  3. Save the file.
  4. Open it in SAM 2026.7.3 and compare outputs.
Expected behavior

AC inverter output power in SAM 2026.7.3 should be the same as SAM 2026.4.16 for a case created in SAM 2025.4.16.

Financial outputs should be the same or very close.

Operating System and Version

SAM 2026.7.3 for Windows

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the default PVWatts / Single Owner case comparison using SAM 2025.4.16 and SAM 2026.7.3 on Windows, checking annual output, NPV, and hourly AC inverter output power. Trace the simulation change from single-year to lifetime outputs and identify why saved 2025.4.16 cases differ; done means inverter output matches the expected prior result and financial outputs are the same or very close.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
desktop
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
45/100

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