Axle VPP new Grid Services mode, compatible with Home Assistant & Predbat

[archyaxleenergy]

We launched the Axle Energy Virtual Power Plant a few weeks ago, which includes optimisation against your bill + earnings from supporting the grid.

We’ve had lots of great feedback, made a ton of updates, and already paid out hundreds of £ of earnings to users whose batteries have exported to help the grid at key times.

After lots of requests, we’ve now added the ability to sign up for grid services only, keeping your existing optimisation setup.

And yes, this means we are now compatible with Home Assistant, or manual scheduling within the Fox app!

This lets you:

• Keep every day control of your battery, to optimise as you see fit

• Participate in events when the grid is under strain (paid at £1/kWh for energy we export)

• Earn revenue from the VPP whilst combining with your favourite optimisation product such as Home Assistant or Predbat.

https://vpp.axle.energy/landing/grid

Please give it a go (or let us know what you’d like to see that isn’t there!) - we still guarantee at least £10 a month and we’re currently offering a £20 signup bonus to new beta users

[WyndStryke]

Just as an update to this, starting from v8.30.0, predbat has added a component to query the Axle REST API and set itself up appropriately.

[jaylo]

Axle seem to be adding a Schedule to the Inverter - which is fine, I think (I use the FoxESS Modbus integration with HA/Predbat, so don't usually use the Scheduler functionality).
But then the Schedule remains enabled once the event is finished, which I think will force it to discharge at the same time every day from then on.
Can Axle remove (or at least disable) their schedule after the event?

[WyndStryke]

They normally clear it within about 30 minutes of the event ending (and often quicker).

It's not 100%, which is why the email which comes after the event asks users to double-check the schedule and clear it themselves if necessary.

[spmaid]

I'm signed up for the Axle VPP events, and that works fine apart from I have noticed that when an export is scheduled from the Mode Scheduler, I can only get about 5kW of export from the Inverter, if I change the mode to be Forced Discharge, I get the full 6kW.

On the attached image, you can see each time the Axle Mode Schedule kicks in, it drops to 5kW, I then quickly override and it bumps back up to 6kW, until Axle refresh the Mode Schedule.

Any thoughts on why a Mode Scheduled export, which is correctly set to 6000W in the schedule isnt managing 6kW but my Forced Discharge is?

[WyndStryke]

Have you got (relatively) recent firmware? I had old firmware (around Jan 2025), and there were odd things happening with discharge speed. Did a firmware update about 5 months ago and everything started working perfectly with Axle.

[spmaid]

I did check that and I appear to be on the latest Firmware versions for my H1 (Gen 1) and HV2600 batteries.

Version_Master：
1.70
Version_Slave：
1.02
Version_ARM：
1.78

[MaterialBarracuda48]

Over the 1hr discharge window, you go from around 5.2kW to almost 6kW at the end.
Maybe the grid Voltage on your local network is affecting the rate?

[WyndStryke]

Oh one thought - this is just battery discharge, you also have to take into account any PV.

(Ignoring losses for simplicity)

If your inverter is 6kW, and and you are getting 1kW from the array, then it'll only pull 5kW from the battery because the inverter capacity is saturated. That'd give you 6kW of AC.

Then for export, you need to subtract any household load. So if your household load is 200W, then you'd be exporting 5.8kW.

Try doing the same graph again, but also add in the entities for solar generation, inverter power, household load, and feed-in.

Inverter power = solar generation + battery discharge - losses

Feed-in = inverter power - household load - losses


Another thing to look at is how the mode scheduler is being configured by Axle during the event. What's the exact mode, do they specify a discharge power? So if they have configured the mode scheduler to only convert to AC at 5kW then that's all you'll get. There are also some modes which can be scheduled via API which aren't options for normal users. For example, force discharge (BAT) is different from the normal force discharge.

[spmaid]

Over the 1hr discharge window, you go from around 5.2kW to almost 6kW at the end.
Maybe the grid Voltage on your local network is affecting the rate?

That's due to the falling Solar, sorry. When the Mode Scheduler is exporting, I am only exporting to grid around 5kW, but when I force it by changing to Force Discharge, that jumps up a kW.

[spmaid]

Oh one thought - this is just battery discharge, you also have to take into account any PV.

(Ignoring losses for simplicity)

If your inverter is 6kW, and and you are getting 1kW from the array, then it'll only pull 5kW from the battery because the inverter capacity is saturated. That'd give you 6kW of AC.

Then for export, you need to subtract any household load. So if your household load is 200W, then you'd be exporting 5.8kW.

Try doing the same graph again, but also add in the entities for solar generation, inverter power, household load, and feed-in.

Inverter power = solar generation + battery discharge - losses

Feed-in = inverter power - household load - losses

Correct, yes, house use during that time is just under 1kW, and to start there was also about 1kW of Solar I think, hence battery discharge starts around 5kW before reaching nearly 6kW at the end of the session, but note the drops when the Axle Mode Schedule kicks in, then briefly drops to zero as I was manually overriding, it then jumps about 1kW higher, until the Axle Mode Schedule is refreshed by them again. They send it several times over the hour session.

[WyndStryke]

During the next event, try grabbing a screenshot of the mode scheduler so that you can see the exact way it has been configured. There are a couple of things which might affect it.

Alternatively, you could drop a line to Axle support asking them to look at the mode & discharge rate which was set for your system (it is a beta test, after all).

[spmaid]

During the next event, try grabbing a screenshot of the mode scheduler so that you can see the exact way it has been configured. There are a couple of things which might affect it.

Alternatively, you could drop a line to Axle support asking them to look at the mode & discharge rate which was set for your system (it is a beta test, after all).

I think I might have, I'll take a look, it all looked ok, and I was able to replicate it, and get the same result, i.e. only 5kW of export (combined battery discharge and PV)

I have added PV, Grid and house load to the chart, and marked up the graphs, in white where I was forcing the discharge (white) then where the Mode Schedule kicked in (pink) showing the export to grid drops to match (ignoring the house loads which also cause dips of course)

I'll mention it to Axle, but I am guessing this is a Fox issue as I can replicate by doing the same, and I just checked the Schedule, it's still there from last week, as it doesnt deleter or even disable once the session is over, I have to manually do that, also attached that.