MPPT 250/100 Solar Charger Voltage Peak every 10 Minutes

Q&A and troubleshooting
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1

I’m observing a strange, very regular behavior on two SmartSolar MPPT 250/100 chargers: the voltage dips exactly every 10 minutes, like clockwork. The attached screenshots show the pattern clearly.

System details:

  • 1x SmartSolar MPPT 250/100, updated to the latest firmware (issue present before and after the update)
  • [Battery type / capacity, e.g. LiFePO4 48 V, 200 Ah]
  • [PV array configuration per charger, e.g. 3 strings of 4 panels in series]
  • [Monitoring via VRM / VictronConnect / GX device]

Symptoms:

  • Voltage dip occurs precisely at 10-minute intervals
  • The interval is so exact that it looks like a scheduled/periodic function rather than a load or irradiance effect
  • I have not yet captured the exact shape and duration of the dip – I plan to hook up a storage oscilloscope to record the transient in detail

What I’ve checked so far:

  • Firmware updated to the latest version – no change
  • Wiring/connections checked

My questions:

  1. Could this be the periodic MPPT panel sweep (the full I-V scan the charger performs to find the global maximum power point)? If so, is a dip of this magnitude on the battery side expected, and can the sweep interval be changed or disabled?
  2. Has anyone seen a similar 10-minute pattern caused by VE.Smart Networking synchronization or a GX/DVCC polling cycle?
  3. Is there any diagnostic data (e.g. via VictronConnect trends or VRM high-resolution logging) that would let me correlate the dips with internal charger events before I set up the oscilloscope?

Any pointers before I start the scope measurements would be much appreciated. I’m happy to provide additional logs or screenshots.

Thanks in advance!

Firmware
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Bildschirmfoto vom 2026-07-06 22-02-53
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Bildschirmfoto vom 2026-07-06 21-57-48
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2

Normal for every Victron MPPT. The MPP algorithm does a broader search every ten minutes.

I dont think its a full scan, wouldnt be necessary anyway, since any panel only has one maximum power point, so by checking the whole range your not getting more information than just above and below the MPP

Expected, yes, since its moving away from the MPP, so a lower power output naturally has to occur. Power output during the sweep is roughly half, at least for what i can see.

No

Its solely caused by the internal MPP tracking algorithm. If the MPPT however operates in U/I limit mode (at the end of a charge cycle for example), then of course theres no MPP to track.

No since its normal operation. But feel free to look at it with an oscilloscope, id be interested as well as to how it actually works “up close”.

For example, a system today saw about 60V PV, while during an MPP sweep it first raised to 70V, then down to 45V, up to 70V, down to 45V, up to 70V, then back to 60V. Pretty sure thats the general profile. Takes about 30s total.

But im sure theres more hidden in the data collection intervall, for example heres a rare (it isnt that rare, looking further at the data) three-dip-sweep. Possibly because it identified a better MPP, since after the sweep the voltage was kept considerably lower

image
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3

Many thanks for the comprehensive answer. For the technicians it would be good to get this information from the Victron documentation.