Solar Panels not working

pilot1each · September 11

I have a TAB 400 BDBC purchased in 12/2025. It has Two 100 AH Battleborn batteries. All Victron products firmware is up to date. I just finished dry camping in the Redwoods at Jedidiah Smith SP. There was little sun. The batteries SOC when we departed the campground was 23%. It is a cloudless day. We arrived at or next destination SOC was 20%. The solar controller never attempted to charge the batteries. We have been on a 5 week trip mostly plugged in to shore power. During our transits in good solar conditions I have noticed the solar output has been diminishing. September 8-10 cloudless skies with few obstructions. How can I troubleshoot to ascertain if the panels are bad or the Victron MPPT has failed. Is it possible to reset the MPPT?

Here is a screenshot of the MPPT history

Horigan · September 11

On a sunny day I would use a voltmeter to confirm the solar panel voltage reading from the Victron app matches what you get when you probe the solar input terminals at the controller. If they match and it shows very low voltage, as shown above, I would check the fuse on solar power line and also check the voltage on the input side of the fuse holder. If those all read low, then that would point to the panels being bad.

If the measured solar input voltage is different from what the Victron app shows, then the controller is bad.

aditto · September 12

Our 2025tab 400 bd solar panels went bad and are currently being replaced by the dealer. Could you show the app screenshot where it shows hourly solar generation chart from a clear day? We found that our panels won't charge in the middle of the day between 12-3pm. In California also. Fell free to message me

pilot1each · September 13

Here is a screenshot of the last 30 days

Solar Panels not working

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