Solar panel puzzle

[royb]

I have a query about how my solar panel system works. The system was professionally installed and does appear to be working satisfactorily, including selling energy back to the grid. However there is one thing it does that puzzles me. It quite regularly, throughout the day and night it appears to be charging the batteries directly from the grid. This is shown both by my smart meter indoor monitor and on the mobile phone app., typically 3kW being consumed, even when I am not using any appliance in the house. This effect is also sometimes be triggered by switching on an appliance, a 1kW load for example, and the smart meter monitor jumps to around 4kW. Switching off the battery controller off (and then back on) restores the consumption reading to the expected 1kW.

Is this effect normal? It seems odd to me that the system is exporting energy and then buying it back at a higher price – but maybe I am misunderstanding how the system works.

The system comprises: 12 x 390W panels (east/west facing); FOX-ESS inverter; 2 x FOX ESS 2600 Batteries Modules and BMS controller.
In the phone app, the setting “enable charge from grid” is set “off”

Roy

 

[Murdoch]

Have you contacted the installers for their opinion ?

 

[royb]

Have you contacted the installers for their opinion ?

Yes, but they have forgotten how to answer the phone

 

[Murdoch]

Yes, but they have forgotten how to answer the phone

Then give them a polite rubbish review on the internet and send them a link to it.

Companies like this don't deserve to stay in business.

 

[binky]

Yes, but they have forgotten how to answer the phone

No need, the subject of using energy unexpectedly has been discussed on here several times. Have a look through the solar posts, it's basically down to inaccuracies of the amp clamp.

 

[Mr Aargh]

Or it could be that it is set up to top up the battery from a night time low cost tariff like Octopus Go. That may be due to minimum and maximum discharge levels. You can (people do) get a battery and no panels and simply load it with cheap power at night and sell it back for a problem fit at peak.

Octopus Flux is similar.

 

[royb]

I don't think it is to do with the low cost tarrif because the charging takes place during daytime as well as at night.
I shall investigate the idea of the amp clamp but I may have to get the experts in as I have no idear how this works.

Thanks

 

[bladerunnerpv]

If you could post some graphs from your monitoring app that would be helpful to understanding what's going on

 

[Andy1733]

Check your inverter for timed charge. If you Google your inverter there's usually a walk through as to what the settings should be.
Just check them all.

 

[Andy1733]

Also check the times it's charging from the grid. Is there a pattern?

 

[yessuz]

could it be that your inverter reports usage incorrectly?

 

[royb]

Andy ... The timed charging feature is switch off, (in the app.)
The charging from the grid is not regular but tends to occur when battery is is low (below 50%)., even though there is enough sunshine.

Bladerunerpv: ... I will try to post some graphs but will wait for a typical day .. today it is overast here in Scotland.

Yessuz: ... I don't think this is the problem because my smart meter monitor is also reporting it.

 

[binky]

Andy ... The timed charging feature is switch off, (in the app.)
The charging from the grid is not regular but tends to occur when battery is is low (below 50%)., even though there is enough sunshine.

Bladerunerpv: ... I will try to post some graphs but will wait for a typical day .. today it is overast here in Scotland.

Yessuz: ... I don't think this is the problem because my smart meter monitor is also reporting it.

what work mode is it set for?

 

[royb]

Bladerunerpv: Here are some graphs from the Fox-ESS controller box. There were two occasions during the day when my smart meter indoor display indicated that the battery was being charged from the mains at 12.30 and again around 2pm. I must admit that I do not fully understand all these graphs but there are a couple of peaks in some of that graphs corresponding to these times.

binks: What work mode is it set for? On my phone app is says "Work Model" = "Self Use"

 

[royb]

Oops.. forgot to attach the graphs
Here they are

 

[binky]

binks: What work mode is it set for? On my phone app is says "Work Model" = "Self Use"

that's the one it should be on.