Sunsynk Inverter Support — Battery Charging, Octopus Tariffs & Solarman Faults
Battery not charging overnight, cheap rate not working, Solarman offline, grid disconnections — we diagnose Sunsynk hybrid systems at the engineering level. Remote-first using Solarman data and charge schedule logs. Independent from Sunsynk and your installer.
Most Sunsynk configuration issues are fixed remotely in a single session. Tell us what you're seeing and we'll work it out.
Book Remote Diagnostic — from £75 → See the Solar Health PlanSafety: If your battery is showing error lights or unusual behaviour, isolate at the DC switch before investigating.
Common Sunsynk problems we diagnose
Every fault below has a proven diagnostic path. Click through for the specific page or book a diagnostic if you're unsure.
Charge window set correctly in Solarman but battery stays at minimum SoC overnight. Often a TOU configuration error, grid charge disabled, or battery SoC minimum threshold too high. Very common after Octopus tariff changes.
See diagnostic guide →The Sunsynk inverter has native Octopus Agile, Intelligent, and Go integration but requires precise schedule configuration. Common issues: charge windows offset by BST/GMT, grid charge enable toggle, SoC target not set high enough. We configure the full schedule remotely.
See diagnostic guide →Battery not powering the house during peak times or grid outage. Could be a discharge schedule configuration error, SoC minimum threshold set too high, or an EPS/backup power circuit issue.
See diagnostic guide →Sunsynk hybrid inverter powered but not generating. Check Solarman for DC input voltage and error codes. Common causes: DC isolator tripped, string fault, or grid connection fault.
See diagnostic guide →Inverter trips off grid due to AC voltage or frequency exceeding G98/G99 limits. Common in areas with many solar systems on the same substation. Reconnects automatically but may need export limiting to prevent repeat trips.
See diagnostic guide →Sunsynk supports EPS (Emergency Power Supply) mode but it must be correctly wired and configured. If the house lost power during a grid outage despite a charged battery, EPS is likely disabled or the load circuit isn't connected to the EPS output.
See diagnostic guide →Solarman (formerly PVMaster) shows no data. Usually caused by the inverter's WiFi/4G datalogger losing connectivity. The inverter continues operating normally. Router changes, password updates, or logger hardware failure are the most common causes.
See diagnostic guide →Sunsynk dataloggers require 2.4GHz WiFi. Many 'monitoring not working' reports after router upgrades are caused by the new router defaulting to 5GHz or using band steering. We reconfigure the datalogger remotely.
See diagnostic guide →Sunsynk fault code index
Sunsynk fault codes appear in the Solarman app and on the inverter display. Common codes relate to: grid voltage faults (E02X series), battery communication errors, DC bus faults, and temperature protection trips. Share your exact code when you book — we identify the root cause as part of the remote diagnostic.
What we do for Sunsynk owners
Remote Sunsynk Diagnostic
We review Solarman data, TOU schedules, and error history to identify the exact fault without a site visit.
Sunsynk Tariff Configuration
We configure your Sunsynk charge schedule from scratch for Octopus Agile, Intelligent, Go, or Flux. Most configuration faults are resolved in a single remote session.
On-Site Sunsynk Repair
EPS circuit verification, DC cable fault location, CT clamp correction, component replacement.
Sunsynk datasheets, manuals & warranty PDFs
Download datasheets, installation manuals, warranty documents and app guides for Sunsynk hybrid inverters and ECCO batteries. Self-hosted and always current.
Sunsynk fault code index
Seeing an error code on your Sunsynk inverter display or app? Our fault code index explains what each code means, common causes, and safe next steps.
About Sunsynk systems — what you need to know
Sunsynk makes hybrid inverters that are particularly popular with UK installers for their flexibility and strong tariff integration. The inverter handles both solar generation and battery storage, with a built-in grid charger that allows the battery to be charged from the grid at cheap-rate times. Sunsynk integrates directly with Octopus Agile, Intelligent, and Go tariffs through configurable Time of Use (TOU) schedules — but this only works correctly when configured precisely. Many 'battery not charging' complaints are actually configuration errors, not hardware faults.
Monitoring is provided by the Solarman app (formerly PVMaster) and the SolarmanPro platform for installers. The inverter's WiFi or 4G datalogger must maintain a stable internet connection for remote data access. The most common searches we handle for Sunsynk: Sunsynk battery not charging, Sunsynk cheap rate not working, Sunsynk Solarman offline, Sunsynk grid disconnect, and Sunsynk Octopus configuration. STS provides independent Sunsynk support — not affiliated with Sunsynk Energy.
Sunsynk questions answered
The most common causes are incorrect Time of Use (TOU) schedule settings, a grid charging setting that is disabled, or the battery SoC minimum threshold being set too high. Sunsynk integrates with Octopus Agile, Intelligent, and Go tariffs but requires correct configuration of the charge windows and grid charge enable settings.
Solarman (formerly PVMaster) requires a stable WiFi connection from the inverter's datalogger. After a router change or password update, the datalogger needs reconfiguring. The inverter continues operating normally even when Solarman shows offline — only monitoring is affected.
The inverter has disconnected from the grid due to a voltage or frequency excursion outside G98/G99 limits. This is common in areas with high solar density. The inverter reconnects automatically once grid conditions normalise, but if trips are frequent, an export limit configuration may be needed.
Yes. We configure the TOU charge schedule, peak shaving settings, and grid charge windows to correctly use your chosen Octopus tariff. This often resolves 'battery not charging overnight' complaints that aren't actually faults — just incorrect settings.
STS supports all major inverter and battery brands — not just Sunsynk. If you have a mixed-brand system or are comparing options, visit the brand hub.
Browse all 19 brands →Ready to fix your Sunsynk system?
Tell us what's happening. We'll review your details and come back with a clear diagnosis path — usually same day.