FoxESS Community - Owners & Installers Forum

Hello,

I had a Fox system installed last month (7 panels, 2xEP11 batteries and a 5kW H1 hybrid inverter). I've also got a Zappi EV charger.

I see on my Fox usage graphs that there is a line called Meter2. From reading this forum, this looks like it's for if you have another set of solar panels that you want to incorporate into the Fox system?

But would it be possible for me to use it to monitor the load to the EV charger, so I can see that separately from the load to the house? Can this trace be set to be "usage" rather than "supply", and is it possible to have two loads like this? (I guess I would have to have the Load clamp moved somewhere so it no longer included the EV charger.) Or must the Load trace always be the total house load including the EV charger? Could I still at least monitor Meter2 and subtract it from Load to get the house usage without the EV?

I'm on Intelligent Octopus Go, so will be force charging my batteries at the same time that I charge the car overnight.

Thanks for your help.

Meter2 is only used to measure an external generation source - the inverter does quite a bit of maths around this metric both locally and in the cloud so it’s usage is strictly limited to that.

If your EV charger load is being seen by the inverter then it will attempt to balance the load from the home batteries so the only way to get round that is to set a charge period at the same time as the EV is charging which is difficult with Intelligent GO. The only way to correct this is to re-configure the wiring so the EV charger is not seen, this could just mean moving the CT clamps location but often it needs a Henley block installing to split the feed just after the smart meter to feed the house/inverter and EV charger on separate feeds.

Thanks for the reply. I thought there might be a limitation like that. It makes sense that it's not just for measuring something, but that it will actually do something based on that measurement.

I don't use the Intelligent Octopus Go app for charging due to one time when my car (an MG4) thought it was a mile or two up the road (though the satnav was fine), and apparently Octopus do a location check before charging, which it then failed as they thought I was trying to use a public charger(??), so it didn't charge. I couldn't risk waking up to an uncharged car again, so I just charge using the charger's app set to 23:30-05:30. I might miss out on the odd extra daytime hour of cheap EV charging from Octopus, but that doesn't really matter.

So setting the Fox battery to force charge from 23:30 to 05:30 won't be a problem to stop the car draining it - I'll be force charging the Fox battery each night anyway. And maybe it'll be useful one day to be able to charge the car from the Fox battery in an emergency?

It was more that I was looking for a way to analyse the load and work out how much just the house uses each day (and hence the cost) so I could compare easily with not having the solar/battery. I wanted to treat the car as a separate expense entirely. I guess I can just export the EV charger's data, which does separate out the EV charger load from the house (even if what it thinks is "home load" is now actually just "grid import" - "EV charger"). It just does this hourly, but I should be able to work from it.

There is always a home assistant, there are really good integrations (programs) to interface the Fox system, Octopus and also for the EV chargers themselves - it’s a bit fiddly to setup and a total rabbit hole once you are into it, and you’ll be measuring and controlling everything possible in the house - but it’s really good at getting a holistic view of total house usage.

Thanks so much for this. Sounds like some interesting, if time-consuming rabbit holes to go down! I'm hoping for something where I can tell people "It saves me X per month, so it will pay off in Y years".

Is it home-assistant.io that you mean?

Yep that’s the one - you can buy a home assistant green which is pre-built and saves all the build and up front learning curve, a few people build their own system which isn’t too difficult if you are tech savvy but it all takes time.

Will has done some videos over the years on setting up - here’s one https://youtu.be/kE_6HtzcyXg?si=2vuGZ9RyRChEjrj9 but take a look at his channel he is an amazing source for information

Excellent - I'll take a look.

Though I think the latest Fox app as of yesterday seems to have a working Revenue feature that I'll also check out as I think it might do what I want.