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Sunsynk · Setup guides

Sunsynk setup & how-to guides

STS engineers explain this setup procedure for Sunsynk systems step by step. Click any topic below for the full guide, or book a free remote diagnostic and we'll tell you what the fix is.
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Had issues with 10yr+ installation. 1 inverter going into alarm mode, unable to access monitoring apps and wanted someone to review and document worthiness of the 2 systems I have. As you will find with older systems, the original installers have moved on, other companies only want to replace and install new, or make up silly prices as they don't want the work, so struggling for 18 month plus trying to source someone to do this. Ronald managed to fit me in the day after contact as he was in the area. Spent a couple of hours on site, found issue with the inverter alarm and he monitoring this to find a total solution, got me back onto the monitoring apps, provided a report on the installations and identified potential areas of concern. These are the people you need for diagnostic reviews of your installations, long term industry professionals, who have a wealth of knowledge gained through working in the industry, know the differing systems and how to contact and approah the companies involved. These are the people you need if you are having issues with installers and / or product and/or supply companies.

M Foster · Jul 2026 Google

Any long suffering Givenergy customers are strongly recommended to use solar tech support. They fixed my battery issue in couple of hours.

Sarma Amirapu · May 2026 Trustpilot

Great service from STS after a power cut and brownout left my GivEnergy inverters effectively useless. After filling the enquiry form out I was promptly given clear instructions by email explaining how to run their diagnostic software and they were working remotely in minutes. Soon after my inverters were back running again. Very helpful and knowledgeable people - thank you.

Dan · Oct 2026 Google

My old solax packed in and was replaced by solar tech support. I am impressed at the very short time scale, sorted in only 3 days. Some were quoting 2-3 weeks. The old unit and all the packing was taken away.

Paul Riddick · Jul 2026 Google

Contacted Solar Tech about my Givenergy battery storage system that wasn't working. Battery status was "idle". Given the company Givenergy had gone bust, I need independent quality technical help. Very patient and clearly very knowledgeable about battery systems Ron diagnosed possible issues and suggested several possible remedies. Worked our way through them and fortunately it began to work. The fault was very specific and only an experienced engineer would have thought to check. Suffice to say I'll be back if I need independent support again. Lastly you only pay if there is a solution. Outstanding.

Mr P · Jun 2026 Trustpilot

Had a problem with my GivEnergy battery which had decided to charge and discharge to a very limited extent. From AI, felt that the problem was probably a calibration issue on the Battery Management System, but which I could not fix myself. So contacted Solar Tech Support, and Ron was brilliant in being able to identify, confirm and fix the issue remotely and very speedily. Thoroughly recommend this outfit

Geoff Henney · Oct 2026 Google

Last updated

What actually needs setting up on a Sunsynk hybrid

On a Sunsynk the hardware rarely needs touching — it is the LCD configuration that decides whether the system behaves. The screen hides a lot behind eight icons (Basic, Battery, Grid, System Mode, Advance, Aux Load, Fault Codes and Li BMS), and the settings that matter most for a UK home all live under Battery and System Mode. Get the battery type, charge schedule and export mode right and the system does exactly what you want; get one wrong and it looks faulty when it is simply mis-set. Our hybrid inverter setup guide walks every screen in the order you would actually configure it.

Three things catch Sunsynk owners out more than any other. The clock does not auto-adjust for BST or GMT, so a one-hour drift quietly shifts your cheap-rate charge window off the tariff. Time slots cannot cross midnight, so an overnight window has to be split into two slots. And on lithium batteries the Protocol number under Li BMS must match your exact battery model, or BMS communication fails and the SoC reads zero. None of these are faults — they are settings.

As independent engineers we are happy for you to follow the guide and set it up yourself for free. If you would rather we did it, a remote setup session is a fixed £145. If something was working and has stopped, or a wrong setting is causing a problem, the remote diagnostic is free and you pay £125 only if we fix it. Anything that genuinely needs an engineer on site starts from £295.

FAQ

Sunsynk setup questions answered

Almost everything that affects day-to-day behaviour lives under two icons. Battery sets your chemistry (Lithium for most UK installs), the charge and discharge amps, and the Shutdown, Low Batt and Restart SoC thresholds that protect the cells — we recommend 20%, 25% and 35%. System Mode controls the rest: Zero Export if you have no export tariff, Solar Export plus the right Max Sell Power if you do, Priority Load so solar covers the house before the battery, and the System 2 timer where you program cheap-rate charging. Under Grid, the mode should be G99/G100 at 50Hz, single phase, 230V, and those are normally set at commissioning and left alone. The full walkthrough is in our setup guide.
Go to System Mode, tap System 2, tick User Timer, then set your cheap-rate window. Octopus Go currently runs 00:30 to 05:30, five hours. Legacy and regional variants exist, including the older four-hour 00:30 to 04:30, so use the times on your own tariff agreement. Either fits in a single slot because it starts after midnight. Set Power to your inverter maximum, SoC to 100%, and tick the Grid box so it charges from the grid. On System 1, tick Zero Export and Priority Load if you have no export tariff. The catch is that slots cannot cross midnight: a window like 23:00 to 05:00 has to be split into 23:00–00:00 and 00:00–05:00. Also check the inverter clock is on the right BST or GMT offset, because a one-hour error is the most common reason a charge window never fires. If you would rather we set it up for you, tariff setup is a fixed £45. If a charge window that was working has stopped firing, the diagnostic is free and you pay £125 only if we fix it.
Yes. If your datalogger is online we connect through SolarMan and configure the same settings you would on the LCD — battery thresholds, system mode, Max Sell Power and your Octopus charge windows — usually in a single session of about 30 to 45 minutes, with the changes confirmed working before you pay. Following the setup guide and doing it yourself is free. If you would rather we did it, a remote setup session is a fixed £145. If something was working and has stopped, or a wrong setting is causing a problem, the remote diagnostic is free and you pay £125 only if we fix it: no fix, no fee. Anything that needs an engineer on site starts from £295.
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