Trying to reconcile various energy figures - and nothing adds up

Energy
1

Hi,

I’m hoping for a quick bit of assistance from anyone with a little more experience than me. Even if that assistance is “That’s how things work, they’ll never add up, just use the AlphaESS for everything”

Very quick bit of background. I’ve just had a battery connected to my solar solution. It’s an AlphaESS one (no idea of model I’m afraid, and I’m using the CharesGillanders integration to read the API). The rest of my solution consists of a Hildebrand Glow IHD connected to my smart meter pumping info via MQTT and a Solax X1 meter which I poll the cloud APIs for via node-red. As a minor complication my meter doesn’t report export over MQTT for some reason, so I’m using node-red trickery to guesstimate (with a reasonable accuracy compared to reading the LCD panel) the export when instantaneous power drops below 0

My issue: None of the numbers add up. Here are yesterday’s figures:

Smart Meter reported consumption: 7.15kWh
Solax reported PV generation: 3.1kWh

AESS Solar generation: 3.6kWh
AESS GridToBat: 0.5kWh (And was 0.7kWh at one point and came back down)
AESS GridToLoad: 6.8kWh (giving a total grid consumption of 7.3kWh)
AESS SolarToGrid: 0.07

So, the battery is reporting 15% higher PV generation and 2% (okay, that’s not so bad) higher grid usage.

I guess my questions are:

  • Why does the battery report different input amounts from the Panels/Grid vs the dedicated devices on those channels? Can I correct this?
  • Given the difference, which reading would be the best to use? The on-channel one for accuracy, or the AlphaESS one for consistency?
  • Why is my battery charging from the grid despite being configured not to?
  • How come I’ve exported some power (albeit a tiny amount) when solar production never went above 0.6kWh, and battery %age didn’t get anywhere near 100%?
  • I’ve got the technical chops to implement MITM proxies for the Solax/AlphaESS devices and not rely on cloud polling. Is this likely to help? (My gut says no - I’ll just get the same figures, but it’s worth an ask)

Any help or advice would be appreciated :slight_smile:

2

In case anyone was wondering, I’ve gone out and had a look at the battery (first real chance since it was installed) and it looks like the battery is reading the main and solar output via CT clamps. This goes a long way, in my mind, ti explaining pretty much everything.

Although discovering the meter on the wall (for reading solar production) doesn’t match the Solax unit - or the Solax App (and, yes, they don’t match each other either) is equally distressing. But I think I’ll just cope with knowing nothing will ever add up 100% and just use the amounts published by the dedicated devices.