Battery discharge is greater than charge

[mjb1416]

I've had my system installed for almost a year now. It all works fine but one thing seems odd. When I look at the Battery Analysis Graph in the FoxESS App for last year, nearly all months show a larger discharge amount than the charge. The flow directions are correct so I don't understand how this can be happing.

[MaterialBarracuda48]

Hello Mike,

Datamonkey posted similar yesterday about numbers not adding up.
viewtopic.php?p=13812#p13812

If you see my reply in the 2nd post, my SoC was 56% from a discharge (from 100%) and after a few hours it increased to 71%.

My system is just over a year old also, it reports 2414.00 kWh battery total charge, and 2165.70 for the discharge.


Either I have Depleted Uranium for battery cells, or more likely the system is inputting some PV energy but not showing it in the logs is one option.

The sensors are just that bad, that they don't add numbers up correctly, which is where you, and I are seeing the difference.

[evilbunny]

My system is just over a year old also, it reports 2414.00 kWh battery total charge, and 2165.70 for the discharge.


Either I have Depleted Uranium for battery cells, or more likely the system is inputting some PV energy but not showing it in the logs is one option.

We have 2 solar arrays, the older system is AC coupled, so that complicates the maths because when the battery is set to charge from the grid at 1W, it still charges from the solar array that's DC coupled.

So yield reports are only production figures from the DC coupled system even though it may have also charged from the older inverter when in self use mode for free too.

I'm not blaming Fox ESS for only reporting the yield from 1 system, I just to make people aware that solar production before and after the battery is installed won't align or add up like it used to.

[mjb1416]

Thanks for the replies. I think the numbers are just wrong and I'll have to live with it. As I said, it's not affecting the operation at all.

[evilbunny]

Thanks for the replies. I think the numbers are just wrong and I'll have to live with it. As I said, it's not affecting the operation at all.

If you're able, you should poke about the API as there is a lot more information collected, stored and able to be reported compared to what is visible in the app or websites.

For example the history API returns 5 minutely values, the data I'm interested in comes as a cumulative total since installation or reset.

Code: Select all

variable: generation
min: 348.1kWh
max: 352.7kWh
diff: 4.6kWh

variable: feedin2
min: 82.7kWh
max: 85.0kWh
diff: 2.3kWh

variable: PVEnergyTotal
min: 299.4kWh
max: 303.7kWh
diff: 4.3kWh

I'm not sure how often or where generation comes from as it keeps reporting as 4.6kWh in other API calls too and doesn't seem to be going up like the other 2.

[mjb1416]

Thanks