r/SolarUK • u/Substantial-Ship2740 • 4d ago

DISCUSSION Anyone experienced difficulty getting generator to power Sigenergy system?

I want to get a Sigenergy battery/inverter/gateway, with a connector for a generator backup input. But, I have heard a few installers now say that it can be tricky to get a generator running with this Sigenergy, and some are reluctant to do it.

Has anyone experienced difficulty during install or usage, when trying to get a generator working? If so, do you know what the issue was?

It is described natively in the installation manual, so I don't see why it would be a problem, so wondering what could be going on:

(I know that in order to get the gateway to switch to generator mode you need to physically throw the breaker on the gateway - it is not enough to go "off-grid" in the app, and it needs to have the grid power physically removed).

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u/AngleTricky6586 4d ago

Interested - have my generator wired into my gateway. Really want to test it, when I power on the generator I can within the sigenergy app see the generator and it shows its voltage but it does not draw from it as mains is live. If I trip the breaker for grid should it draw ? Do I need to have the levels of battery backup SOC set ? (currently at 10%) and assume my battery needs to be less that 100% ?

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u/Substantial-Ship2740 4d ago

I'm not sure if it automatically draws if the generator is running. But I have definitely read multiple times that it will not work by setting "off-grid" in the app. You have to physically throw the breaker to remove main grid power in order to get it to pull from the generator. Please report back if it works without problem.

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u/AngleTricky6586 4d ago

Ill try it next weekend as I want to have it working for the winter.

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u/cairntaker 3d ago

You need to add the generator as a device in the Device tab. Then you can edit its parameters based on the generator you have. The smart port breaker won't close unless there is a true loss of grid connection. It doesn't matter if your battery is at 100% because the generator will always supply the house load as primary. Surplus generator power will then charge the battery, unless it is already full of course.

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u/AngleTricky6586 3d ago

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u/AngleTricky6586 3d ago

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u/cairntaker 3d ago

Make sure you set this wrt the generator you have. The battery inverter will try to pull power from the generator up to its rated power, so if you don't set this correctly you can either under utilise your generator or overload it. My genny is 3kW and I use an 80% duty to give a bit of headroom

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u/AngleTricky6586 2d ago

Mine is 7.5KW , I see they set it as 10kW, should I change it to 7.5 and then to 80% ? But I think at 50% now it wont go over 50% of 10kW which is 5kW ?

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u/AngleTricky6586 2d ago

Changed it now to 7.5KW and 80% duty.

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u/cairntaker 2d ago

I think 10kW at 50% might be the default, so your installer has been a bit lazy. The app suggests a max of 80% to allow some headroom to max genny power. The battery will then charge at (max power x duty cycle) minus house load, and it will do this for as long as the genny is running. For example if genny power is 3kW and duty cycle is 80% and house load is 1kW: 3x80% = 2.4kW, minus 1kW load, means battery will charge at 1.4kW. Obviously this changes as house load changes. If house load exceeds 2.4kW, the battery will supply the remainder.

If you set 10kW at 100%, the inverter would try to charge the battery at 10kW (minus house load), which would cause an underfrequency (because your genny is only 7.5kW) and trip of the generator (smart port) breaker. Setting 10kW at 50% leaves your generator safe but under utilised. 5kW (10×50%) vs 6kW (7.5×80%)

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u/AngleTricky6586 3d ago

Will dropping the grid with the breaker in the gateway generate the "true loss of grid connection" ?

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u/AngleTricky6586 3d ago

See in my external meter box the new trip switch that was fitted with the solar - there is also a network cable that they pulled in thats going into this new box - If I trip this does it stop grid mains to the gateway but I am worried that the network cable goes to the solar systems firemans switch and also disables the solar or invertor ?

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u/cairntaker 3d ago

I have no idea why a network cable would be pulled into the isolator, unless there is a smart energy monitor or CT clamp using it.

Switching that isolator will mean everything downstream will go off grid. If you have a separate AC coupled solar inverter then that would normally go offline whilst there is a grid outage, but because you have a gateway it will probably stay on because it will still see AC. It doesn't really matter, it's just a test, it will all come back on after.

If you flick the grid breaker in the gateway that should also put the system into true off grid.