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Solis OV-DC: DC Overvoltage

Updated June 2026 · Reviewed for technical accuracy · ~3 min read

OV-DC (DC overvoltage, code 1020) means the voltage coming from your solar panels has exceeded the maximum the Solis can safely accept. This matters: over-voltage on the input can damage the inverter, which is why it stops. The common cause is a string with too many panels for the inverter's window, and it shows up most on cold, bright mornings.

Why PV voltage goes too high

  • Cold weather. Solar panels produce a higher voltage when cold, so a string that is fine in summer can spike over the limit on a freezing, sunny morning.
  • Too many panels in a string for the inverter's maximum input voltage. This is a design issue if it happens regularly.
  • A transient spike at start-up.

What to do, safely

Over-voltage can damage the inverter. If OV-DC is showing, the priority is to stop pushing high voltage into it. Turning off the DC isolator is the safe action; measuring string voltages and changing the array is an installer's job.
  1. Turn off the DC isolator. This disconnects the panels and stops the over-voltage reaching the inverter.
  2. Note the conditions. Did it happen on a cold, sunny morning? That strongly points to PV string voltage, and it may ease as the panels warm up.
  3. Do not just keep reconnecting. Repeatedly feeding over-voltage into the inverter risks damage.
  4. Call your installer. They measure each string's voltage with a meter and, if a string is over the limit, redesign it with fewer panels per string. That is the real fix for a recurring OV-DC.
When to bring in a professional A recurring OV-DC means your array voltage is exceeding the inverter's input limit, which your installer needs to correct by checking the string design. Don't keep reconnecting a system that is over-volting the inverter.

Related Solis codes

UN-BUS, DC bus low Reve-DC, Reversed DC DC-INTF, Abnormal DC current

FAQ

Why would cold weather cause OV-DC?

Solar panels produce a higher open-circuit voltage when they are cold. On a freezing, sunny morning a string can briefly spike above the inverter's input limit, triggering OV-DC until the panels warm up.

It only happens occasionally. Is that fine?

An occasional, weather-driven OV-DC that clears can be manageable, but because over-voltage stresses the inverter, it is worth having your installer confirm the string sizing is within the inverter's input range.

Sources

  • Solis inverter alarm-code list (OV-DC = DC overvoltage; check input voltage does not exceed maximum).
  • Solis installer documentation.
⚠️ Safety disclaimer. Solar inverters carry lethal DC and AC voltage even when "off", and PV inputs are live in daylight. This guide covers turning off the DC isolator only. String measurement and array changes must be done by a licensed installer.