I came across this issue with Victron Solar Sense 750 today. The instantaneous readings are recording in various data systems (VRM/Node-Red/Influx). However, in one unit today, the Daily Yield total which is a cumulative data field reset to zero. In the first screenshot, the top graph is the instantaneous recording of W/m2. The Graph below is the cumulative yield field and just after 1200 hrs it drops from a cumulative of 2kW to 0 kW. Daily Yields SS & MPPT - Grafana.pdf (384.1 KB)
A screen print from the VRM portal show the same occurrence with the red Graph Line. The green graph line which is another Solar Sense unit is showing small losses from the cumulative data field but not resetting to zero as one of the units did today. VRM Daily Yields Graph.pdf (342.8 KB)
Is anybody else encountered a similar issue? I will send the information through to the dealer on Monday.
Hi @McKillop, this behaviour indicates that the SolarSense has lost its real-time clock timestamp somehow. Instead of relying on the RTC, the SolarSense falls back on irradiance-based determination of when a new day starts.
If you reconnect to the SolarSense using VictronConnect, the RTC will be resynchronized and the misbehaving unit should behave identical to the other units.
What are the first four digits of the serial number of this unit? (e.g. HQ2544 or HQ2613)
Hi Luc,
The first 6 digits of the serial numbers for all 3 unit are HQ2606.
I sent some information to the supplier this morning and it covered 4 weekly time periods spanning both June and July 2026. I did a firmware update to the units somewhere around 1 July 2026 to version 1.02. This should have resynchronised the units at that time. The behaviour that I referenced is evident both in June and July.
I have resynchronised again just now and I will see if the behaviour continues.
I am attaching a screenshot from 17 July 2026. One solar sense unit resets itself to zero (red Graph line) a few minutes past noon. The unit represented by the (Green Graph line) does not reset to zero but drops a small increment between 0.1-.02 Watts on two instances.
As you state, this may be related to the time clock, so the resynchronisation that I did today may indeed address this matter. VRM Daily Yields Graph.pdf (342.8 KB)
Yesterday I connected to the Solar Sense units via Victron Connect. They all reset the accumulated Yield to zero at a synchronised 0001, or so, hrs. Today however one of the three units reset twice to zero as per the attached screenshot. 2026-07-21 at 12.07.50.pdf (275.5 KB)
It would appear that connecting to Victron Connect for a RTC synchronisation did not achieve the desired result of the units recording accumulated daily yield data consistently.
Hi @McKillop, in that case, something is wrong with this unit. Seeing as you’re already logging to Grafana, can I ask you to record the TimeSinceLastSun and BatteryVoltage topics?
My hunch is that the unit is unexpectedly reset for some reason, with a battery disconnect seeming the most likely.
Can you also send me the Battery Voltage graph from the History page in VictronConnect?
Hi Luc,
I wasn’t logging the TimeSinceLastSun to Influxdb and as such cannot get you the historical records for this immediately. I altered the .conf file and will be able to get you the data record from here onwards. I will give it three days of data and will then attach the records for you. Let me know if you would like something sooner or if a longer record period than 3 days is preferred.
I have attached the battery Voltage for the past week.
The Victron Connect History graph for Battery Voltage is greyed out and cannot be selected.
Hi @McKillop, thank you for the assistance. (Un)fortunately there is no clear dip in battery voltage, although /20/ does seem to swing a tiny bit more. /20/ is the misbehaving unit correct?
It might be the case that battery voltage is only available on the VictronConnect beta. At least I can see it on v6.40beta9. Note that the info is under the “History” tab, not the “Trends” tab.
Hi @CZvacko, yes TimeSinceLastSun should work as far as I know. If there is a lot of light pollution it might be that the irradiance never drops below the “No sun” threshold, but then I hope you have some good blinds on your windows.
I works by recording the time since the last sun. During the day the record is zero. The time count begins from when the unit records no sunlight and continues until first light is recorded. The attached graph is from the early posting to Influxdb before I rationalised the data collection. 2026-07-21 at 12.07.50.pdf (275.5 KB)
My error, I was looking under trends and failed to see the graphing under history. The voltage for the unit is attached. It covers 6 July to21 July (Today. VictronConnect SS Voltage.pdf (313.9 KB)
Oh, so that’s for sunset, not sunrise. Somehow I overlooked the fact that it was meant the opposite way. Then it works correctly. At night, Grafana displays some numbers.
Hi @McKillop this plot seems to indicate an unscheduled reset at 05:00 on July 16th, but the battery voltage does not dip so the reason why I do not know. Can you zoom in to see if there is a period of “missing” advertisement packets?
When I go to a data table view all three units record roughly every 1 minute at a minimum but there are many records in each of the three where the data record is only 10 seconds apart, others are spaced 20 seconds apart, some 40 seconds, some 50 seconds. This was only a quick view of the records for the past 3 hours.
The Solar Sense units performed without anomalies for the past 4 days up until 1100hrs today. Since installation 6 weeks ago, one unit has performed without error. One unit performed with errors but has not had a performance issue in the past 4 days (since connecting via Victron Connect). One unit has continued to have intermittent issues. I have attached graphs with the recorded data over varying time periods covering the last 4 days. 1HR Voltage Yield.pdf (343.4 KB) 7 Minute Battery:Yield.pdf (264.8 KB) 60 Hr Voltage Yield.pdf (378.3 KB) 60HR W:m2 - Time since last Sun.pdf (413.1 KB)
I also noticed something strange about the daily yield reset. I retrieve data from Cerbo via MQTT. For the first 14 days after installation, the peak daily value was observed at 0:00 (technically the next day), and then it reset. But now, for the last 4 days, the peak daily value has been observed at 22:30 or 23:00 (on the same day). This has caused some queries and calculations in Grafana to stop working.
@Luc It also looks like an RTC issue. The reset does not occur at a predictable time. Or has the Cerbo somehow affected the process of resetting the data?
My observations are that the Solar Sense is a one way communication system similar to the Battery Sense and that the Cerbo has no control over the unit, it simply receives the data via BLE.
My information in the past few weeks has indicated 2 issues. The first is a reset to zero between 2230hrs and 0001 hrs. The second issues is resetting the cumulative yield at random times during the day but not always resetting to zero.
If it is a RTC issues then this would explain both occurrences.
My gut feeling is that it is an issue with one of the components on the logic board of the Solar Sense. Possibly related to a RTC or a memory function controller. This is purely unsubstantiated guessing. I can find no correlation to any weather conditions at the times of the issues. Additionally one of the units has not had a single fault and none of the units has had issues at concurrent times.
Then it works correctly. At night, Grafana displays some numbers.