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Maximising feed-in
Posted: Tue May 16, 2023 10:31 am
by AdamT
Hi,
We had our panels installed about 2 weeks ago and it's all looking great. So good in fact that we're interested in the Octopus Flux tariff when we get our grid paperwork through. We've got 6 panels facing east, and 9 facing west, which is when it looks like we could get a very good feed-in price. My question is about whether it's possible to maximise our grid feed-in at peak times (4-7pm), by setting the battery to discharge some of its' energy during this peak time?
Thank you.
15 solar panels, 6kW
Fox Ess 3.7kW hybrid inverter
20.5kWh Foxx Ess battery system
Kia e-Niro EV
Zappi EV charger
If I could add to the above, we're now on Octopus Flux - much quicker and easier than I thought, so, thank you Octopus. I'm now going to charge the car with surplus energy from 11-4pm, which may be enough during the summer. However, I did notice yesterday that during peak feed-in time, the battery was charging up. Even if it's not possible to force it to discharge, would there be a way of just stopping it from charging? Thank you
Re: Maximising feed-in
Posted: Tue May 16, 2023 4:35 pm
by asyrop
This query seems to be popping up in various posts.
For example in:
viewtopic.php?t=288
My reply then was:
Sat May 13, 2023 10:02 am
Hi All,
Unless I have it wrong, there are 2 aspects to this question. Currently, I can stop the solar PV being used to charge the battery during peak Flux hours in the afternoon by selecting the "Feedin" option on the website control, and indeed it uses the same password as for the website (and app) as set by my installer. So all is as described in this post.
However, this only stops excess solar from charging the battery is does not force the battery to discharge during this period. I believe the work mode listed to achieve forced discharge is/wiil be "Power Station". Everytime I have tried to select this mode, the response is one of invalid parameter, which I take to mean that Fox have yet to enable this feature.
You may be aware from the published datasheets and manuals that Fox specifically report that their system does not allow a battery to discharge to the grid, but only to support the "house" demand when needed (work mode "Self use). Clearly, to make good use of the Octopus Flux tariff, Fox need to change this aspect the firmware which I am hopeful about with the appearance of a "Power Station" option even if it is yet to work.
There are parameters that an RS485 connection, via the dedicated serial port, and suitable external control can do that Fox currently do not provide control of via website or app.
Does anyone know when they might update this side of their controls ? or have I missed something ?
Alan
Hopefully this gets you started on your options - I am waiting on any contradictions or additional comments to my post just now
Alan
Re: Maximising feed-in
Posted: Tue May 16, 2023 4:46 pm
by Ched
AdamT wrote: ↑Tue May 16, 2023 10:31 am
Hi,
We had our panels installed about 2 weeks ago and it's all looking great. So good in fact that we're interested in the Octopus Flux tariff when we get our grid paperwork through. We've got 6 panels facing east, and 9 facing west, which is when it looks like we could get a very good feed-in price. My question is about whether it's possible to maximise our grid feed-in at peak times (4-7pm), by setting the battery to discharge some of its' energy during this peak time?
Thank you.
15 solar panels, 6kW
Fox Ess 3.7kW hybrid inverter
20.5kWh Foxx Ess battery system
Kia e-Niro EV
Zappi EV charger
I don't believe it's very easy to discharge the batteries during the peak export rate - there are various hacks like fiddling the CT clamp and there is a HA addin that gets RS485 data and I believe can change modes but I haven't tried that.
One thing you can do very easily is set a force charge before the peak to ensure your batteries are full, then all excess solar will be exported. That's what we have been doing and our first month on Flux worked out at about 21.06p/kwh import and 25.4p/kwh export. We do also run washing machine and dishwasher on the cheap rate overnight and always charge the batteries on the cheap rate too. That way as soon as we start generating it goes straight to export.
Re: Maximising feed-in
Posted: Wed May 17, 2023 5:15 pm
by AdamT
Thank you both, Alan and Ched,
Very interesting and helpful. So for the time being, I'll need to try to make sure battery is at 100% at 4pm, and at some point in the future there may be an upgrade that helps.
Many thanks,
Adam
Re: Maximising feed-in
Posted: Fri Sep 01, 2023 5:07 pm
by CraigHUk
Hi Guys, sorry for rekindling this post, but what is your opinion of the flux tariff, do you make it work for you? I have been analysis my bills and also my usage via octopus api's to check Agile, and from what I can see its hands down cheaper for us without taking into account battery discharge etc (which it looks like isn't possible on FoxEss systems without trickery). I am yet to compare the flux alternatives, but thinking where possible I want to drive down our costs and make the most use out of the cheap overnight rates where possible.
Re: Maximising feed-in
Posted: Sat Oct 14, 2023 2:05 pm
by UK_KH_User123
Hello... I also might want to do some battery feed-in from my KH 10.5 inverter.
I just wanted to post that the RS485 connection does provide some more options (and much quicker updates) than the web site interface, but it does not provide any controls that are not also available from the front panel menu system of the inverter. So, if the inverter doens't let you choose 'Power Station' mode on the front panel, the RS485 won't let you either.
https://github.com/nathanmarlor/foxess_modbus
Re: Maximising feed-in
Posted: Mon Oct 16, 2023 10:04 am
by calum
My Mum has recently had a Givenergy system installed, with the option to force discharge her battery on a schedule, but it seems Givenergy are significantly ahead of Fox when it comes to the more "advanced" options. But it shows there's nothing stopping it in principle, I assume they are just not that quick when it comes to firmware development.
And yes, the RS485 is no magic bullet, other than it lets you automate things via HA or NodeRed or whatever. But everything it does could be achieved by pushing buttons on the front panel of the inverter.
Re: how to set up battery to import from the grid
Posted: Sun Oct 06, 2024 10:08 pm
by Mitch23232323
CraigHUk wrote: ↑Fri Sep 01, 2023 5:07 pm
Hi Guys, sorry for rekindling this post, but what is your opinion of the flux tariff, do you make it work for you? I have been analysis my bills and also my usage via octopus api's to check Agile, and from what I can see its hands down cheaper for us without taking into account battery discharge etc (which it looks like isn't possible on FoxEss systems without trickery). I am yet to compare the flux alternatives, but thinking where possible I want to drive down our costs and make the most use out of the cheap overnight rates where possible.