Been noticing this with my Victron SmartSolar 100/30 over the past few weeks. During the colder mornings we've had lately, the actual output feels noticeably higher than what the controller's logging — panels are clearly producing well in the crisp conditions but the figures look a bit flat.
From what I've read, it's partly down to how the MPPT calculates things at lower cell temperatures. Silicon panels actually perform better in cold weather (lower temps reduce resistance), so there can be a mismatch between what the controller expects and what's physically happening, especially during that first hour or two after dawn.
A few things I've been trying:
- Double-checking my panel temperature compensation settings in the VictronConnect app
- Comparing the Victron readings against a clamp meter on the cable
- Logging daily yield manually for a couple of weeks to spot patterns
The clamp meter comparison has been the most revealing — there's a consistent gap on cold clear mornings that closes up by midday.
Curious whether anyone else has seen this across different brands. I'd imagine cheaper controllers might handle it differently to Victron. Also wondering if it's more pronounced on certain panel types — mine are fairly standard 200W poly panels, nothing fancy.
Has anyone actually contacted Victron support about it, or found a firmware version that seems to handle cold-weather calibration better? I know there have been a few updates over the past year.
Would be good to get a sense of whether this is widespread or just something quirky with my particular setup.
