I received a prompt response and excellent technical support for the remote diagnosis (Oxfordshire) and resolution of my GivEnergy EMS configuration. My GivEnergy issue involved a single inverter and battery that had a loss of calibration, a critical low voltage drop. It needed a recovery and re-calibration, and was supported via email into yesterday evening being resolved within 24 hours. Ron demonstrated a very high level of knowledge and experience in the intricacies of a GivEnergy EMS configuration, even surpassing the understanding of GivEnergy itself when it was still operational. I have already recommended their services to a neighbour as I’d be happy to use their services again based on the fair pricing and the quality of their support.
Sunsynk Battery Not Charging — System Mode, SolarMan and BMS Faults
- Most common Sunsynk issue
- Applies to all Sunsynk hybrid models
- Usually fixed remotely in one session
This diagnostic guide covers every setting that can prevent charging. Work through the steps in order — most cases are resolved by the third step.
Book your free remote diagnosticSunsynk hubSafety: Isolate at the DC switch if you notice any error lights on the inverter or battery.
Ronald was able to organise a brilliant electrician with extensive experience of GivEnergy systems local to me in the SW. I have now got a fully functioning system and suspect that my electricity bill will be substantially reduced or in credit over a year. Also when said electrician discovered an overvoltage in the my local grid, Ronald prepared a very lucid and comprehensive report of the situation which I have now supplied to my local grid. Cannot recommend Ron and Dan enough.
Excellent service from Solar Tech Support. Extremely quick to respond, easy to deal with and clearly very talented engineers. They were persistent throughout a complex GivEnergy battery issue and resolved everything completely. Highly knowledgeable, professional and reassuring support from start to finish. Highly recommended.
⭐⭐⭐⭐⭐ Absolutely Outstanding Service! My GivEnergy system had completely gone down, and unfortunately I was getting absolutely no support from either the original fitter or the supplier. I was left completely stuck with a system that wasn’t working. I contacted Solar Tech Support and they were absolutely brilliant from start to finish. They quickly got to the bottom of the problem, knew exactly what they were doing, and managed to get my entire system back up and running. Hands down, these guys are absolute experts in their field. The level of knowledge, professionalism and customer service was exceptional, especially when I’d already been left without any support elsewhere. If you have a GivEnergy system and you’re struggling with an issue, don’t hesitate to contact Solar Tech Support. I honestly can’t recommend them highly enough. 5 stars all day long! 🌟🌟🌟🌟🌟
Our 3 year old GivEnergy batteries froze. They were showing 0% on the app, but they were fully charged. Some how Ron took over our inverter and remotely cured the problem. We live in King’s Lynn, he is in Leeds I believe. Very grateful.
Ron is incredibly knowledgeable about solar installs in general but knows givenergy products inside out and the key personnel that worked there from the start to the end. My problem was spurious in its nature but Ron spotted it straight away when he understood the installation details. In essence the installers didn’t fit the correct trip switch. He also gave me hope that in the future hardware repairs could be possible but it’s still early days. This guy really is in the know and keen to sucas a business If you need help don’t hesitate
6-step diagnostic process
Work through these steps in order. Most battery charging issues are resolved by Step 2.
Check System Work Mode in SolarMan
Log into SolarMan, navigate to Device → Settings → System Work Mode. If the mode is set to Selling First, this is almost certainly your problem. Selling First mode maximises grid export and does not force charge from the grid or solar. Change to Time of Use (or the mode appropriate for your tariff) to enable charging windows.
Check SoC target and minimum SoC headroom
In SolarMan, check the State of Charge (SoC) settings: target SoC (maximum charge level) and minimum SoC (discharge floor). If the battery is already at or above the target SoC, the inverter will not charge further — there's no work to do. For example, if minimum SoC is 90% and target is 90%, charging will never happen. Set minimum SoC to ~10-20% and target to 90-100% to allow the system to charge from near-empty to full.
Check BMS communication status
In SolarMan, on the Device page, check the battery status. It should display a valid percentage (e.g., 45% SoC, 78% SoC). If the battery shows 0% or Unknown, the inverter has lost communication with the battery BMS. This prevents charging entirely. Check the CAN or RS485 communication cable between the inverter and battery — it may be loose, disconnected, or damaged.
Verify charge schedule times and timezone
In SolarMan, check the Time of Use charge window times. The window must exactly match your tariff's cheap-rate period. Common windows: Octopus Flux off-peak 02:00–05:00 · Economy 7 approximately 00:30–07:30. Octopus Go windows vary by Go variant, so take the hours from your own tariff agreement. Also check that the inverter clock is set to current local time. During British Summer Time (BST), if the clock is still on GMT, the window will fire 1 hour late.
Confirm grid charge is enabled
In SolarMan, find the grid charge settings (usually under Device → Settings → Grid Charge). Verify that grid charge is set to ON for the time windows where you want the battery to charge from the grid. If grid charge is disabled, the battery will only charge from solar generation, not from cheap-rate grid electricity.
Check CT clamp orientation if applicable
If your Sunsynk has a CT clamp installed (for import/export monitoring), check that it's oriented correctly. Portals differ on which sign means import, so do not rely on the sign alone. Test it by behaviour instead. At night, with no solar and the battery idle, note the grid figure in SolarMan. Switch on a kettle. The figure must move further in the import direction. If it moves the other way, the CT clamp is reversed. This can prevent charging from activating correctly.
About Sunsynk charging issues
Sunsynk hybrid inverters (3.6kW, 5kW, 8kW, 12kW models) are widely installed across the UK from 2020 onwards. They integrate directly with SolarMan monitoring (formerly PVMaster) and support native Octopus Agile, Intelligent, and Go tariff integration via Time of Use schedules. However, the SolarMan portal doesn't always clearly surface these settings, and many systems are delivered with factory defaults rather than customer-optimised configuration.
The result: nearly 30% of Sunsynk owners report battery not charging overnight despite having a charged battery and a cheap-rate tariff available. In almost all cases, it's a settings issue — System Mode set to Selling First, SoC headroom exhausted, or timezone mismatches — not a hardware fault.
Sunsynk battery charging questions
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