@johnnyb I would say that is normal. Inverters I believe, control current flow by adjusting voltage levels so the power from various sources is directed into your home. Unfortunately the voltage on the grid also fluctuates which causes momentary imports from the grid into your home instead of from your batteries, however the inverter should react to this and adjust itself to get the battery back supplying your house.

This happens on my solar / battery system and is normal I would say. I also see on occasions power actually being exported to the grid for brief moments ( 2 to 8 seconds ) again due to voltage fluctuations on the grid etc. Up until today however I was not getting paid for the exports! 😀

Regards

Posted by: @johnnyb

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I've recently had a Solis hybrid inverter fitted, with a battery, and I am surprised to see that my energy use in the Octopus app shows between 130 and 300W used every half hour of the day while running off the battery/solar. This is average out at around 400Wh use all the time, plus the amount I have used overnight to charge the battery.

This doesn't seem normal, it seems a lot of energy to use.

The electrician who fitted it is coming out on Friday so I wanted to ask what other people are seeing on their bills before he comes.

Yes, you will have some import unfortunately.

The inverter as mentioned above will sometimes overshoot as it tries to balance the demand.

You may also exceed your inverter rating if the demand is greater.

300w is very high though every half hour (unless your inverter rating is maxed out and additional import is needed).

My inverter tends to overshoot on average by about 20w an hour (and undershoot also, but I don't have an export licence and can't claim that back).

@bash If I am to believe the Tesla app, the Gateway will ‘phone home’ and sniff the grid every so often during the hours set to use battery power (higher rates of tariff). Perhaps @transparent may know, if this is some form of ‘housekeeping’ routine to keep the system in sync with the grid perhaps. The connections shows a draw of 0.1 kW for perhaps 5 seconds or so then ‘hangs up’ again. Regards, Toodles.

Posted by: @toodles

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@bash If I am to believe the Tesla app, the Gateway will ‘phone home’ and sniff the grid every so often during the hours set to use battery power (higher rates of tariff). Perhaps @transparent may know, if this is some form of ‘housekeeping’ routine to keep the system in sync with the grid perhaps. The connections shows a draw of 0.1 kW for perhaps 5 seconds or so then ‘hangs up’ again. Regards, Toodles.

I don't know Toodles. We have a Solis inverter, very similar to @JohnnyB and I was referring to this more specifically. I am not familiar with the Tesla Powerwall.

@bash I was thinking that maybe this might be a generic practice for systems attached to the grid, hence my asking if @transparent might know. Toodles.

Yes @toodles - I believe that the majority of grid tied equipment with the potential to export do indeed draw small quantities of power from the grid.

In the Sunsynk inverters, which are relatively new to me, I notice that there is a parameter which can be configured to say how much this Trickle Current can be.

I'm not wholly convinced that the reason stated by Sunsynk is the entire story.

However, I can imagine that all inverter manufacturers would err on the side of drawing enough electricity to prevent pre-paid meters cutting power to the home.

Posted by: @johnnyb

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I've recently had a Solis hybrid inverter fitted, with a battery, and I am surprised to see that my energy use in the Octopus app shows between 130 and 300W used every half hour of the day while running off the battery/solar. This is average out at around 400Wh use all the time, plus the amount I have used overnight to charge the battery.

This doesn't seem normal, it seems a lot of energy to use.

The Solis S6 has various modes of use. I currently have it self to prioritise self use. I created a soliscloud account and use the app to change the config (a bit more is available via the buttons on the inverter). There is also browser based access to soliscloud.

This is set under "Storage mode". In that same user menu, you also find various settings like export controls, calibration (I left at the default -30), whether the battery can or not be charged from grid, etc.

I find the app useful to check what is happening (in the attached screenshot, the power being used by the various circuits is shown). By default, it only updates info every 5 minutes, but you can ask Solis to change this. 

This isn't working out as a small amount.  I've downloaded the half hourly import readings from Octopus this evening and it is averaging 370W per hour when the battery is discharging, or 6.6kWh or nearly £2 worth in the 18 hours the battery isn't charging. I think there is something wrong as that is rather a lot of electricity.

If anyone else has half hourly bills or can download their use in a spread sheet it would be interesting to here what is normal.

@johnnyb I added that to the Solis inverter thread

I get 0w import during the day

@batpred I may be asking you for more info in how you have your inverter set up as it seems a similar model to mine.  I have just seen your post with the screenshot of your Octpus account and no import during the day.  That is reasurring as mine looks quite different to yours at the moment.

The electrician so coming out tomorrow to run through a few things with me and I will ask him if there is anything he is aware of that needs changing.

Edited to add:

I see we posted at similar times. I am going to read through your posts about your inverter and see what info I can glean.  Thanks.

@johnnyb I have a Growatt, and I download my half hourly data from Octopus and analyse it every month. Other than peak winter when heat pump is running, we don't import from the grid outside the off-peak hours. Maybe, occasionally like 20 Wh. and that too only briefly. But, not to the tune of 6.6 kWh in a day.