Understanding Axle's Battery Optimisation
This guide explains how our optimisation works, what you should expect to see day-to-day, and how to know if everything is working correctly.
- We use your tariff, energy usage, and solar forecast to save you money
- A fresh plan is sent to your battery around midnight each day
- Schedules are simpler for dual-rate and complex for dynamic tariffs (like Agile)
- Grid events add extra earnings - your schedule adapts to these when profitable
- Battery health is protected by limiting cycles & respecting state of charge limits
Our Goal: Maximise Your Savings
Our primary goal is to maximise your financial savings from your battery system. We do this by intelligently managing when your battery charges and discharges, based on several factors. In order, we prioritise:
- Your bill: We try and reduce your energy costs as much as possible, based upon your import & export tariffs, local solar production, and household consumption.
- Battery health: We manage your battery to ensure a long and healthy life.
- Grid earnings: We look for opportunities to earn you extra money from grid services.
How We Create Your Schedule
Every day, our optimiser creates a custom plan for your battery. This plan is based on:
- Your Electricity Tariff: We use your import and export prices for every half-hour of the day.
- Your Household's Energy Use: We look at your recent consumption patterns (from your smart meter and battery) and other forecasts to predict how much energy your home will need.
- Solar Forecast: We use a weather forecast for your specific location to predict your solar generation.
- Your Battery's Status: We take into account its current charge level, capacity, and power rating.
What to Expect Day-to-Day
The main event happens every night, typically around 00:15 UK time which will last for the next 24 hours.
Intra-Day Adjustments
Often, we need to update your schedule during the day. This can happen if there's an opportunity to participate in a paid grid service event, if the solar or demand forecast changes, or if your battery reconnects after being offline. You can expect a few of these intra-day adjustments on a busy day.
Single & dual-rate tariffs
If you have a tariff with a simple peak and off-peak structure, your schedule should be relatively straightforward. Your battery will charge from the grid during the cheap overnight period. During the day, you'll use your stored energy (and any solar) to power your home, avoiding expensive peak electricity. We also look for opportunities to use your battery for paid grid services, which can lead to extra charging or discharging through the day for which you’ll be compensated. We will never participate in those services if it would leave you in a worse off financial position.
Daily schedule view
Example dual-rate day
Real-world timings vary slightly with your tariff.
| Time | Action |
|---|---|
| 00:30 – 06:00 | Charge at 7p/kWh (cheap night rate) |
| 06:00 – 23:00 | Self-use (battery powers the home all day) |
| 23:00 – 00:00 | Discharge take advantage of energy left and grid services |
Dynamic tariffs (e.g., Octopus Agile, Flux, Cosy)
If you have a dynamic tariff where prices change multiple times in a day or even every half-hour, your schedule will be much more active. Your battery will charge when prices are lowest, which might be overnight or even during the day if prices dip. It will discharge to power your home when prices are high, and may even export to the grid if you have a compatible tariff and export prices are attractive. Expect the schedule to be different every day as it adapts to changing prices.
Daily schedule view
Example Dynamic tariff day
Real-world timings vary slightly with your tariff.
| Time | Action |
|---|---|
| 00:00 – 02:00 | Self-use (overnight) |
| 02:00 – 05:00 | Charge at 6-9p/kWh (cheapest periods) |
| 05:00 – 08:00 | Self-use (morning demand) |
| 08:00 – 16:00 | Feed-in (solar exports, battery holds charge) |
| 16:00 – 18:00 | Discharge for high export tariff and grid services (evening peak) |
| 18:00 – 00:00 | Self-use (Evening) |
A Checklist of Expected Behaviour
It can take some getting used to a battery that operates automatically. Here’s a friendly guide to what typically happens and the moments when a quick check-in helps.
What a healthy day looks like
- Night top-up usually means a planned charge during your cheap-rate window (often 00:00–05:30).
- Evening cover keeps discharging across the late afternoon and evening peaks, sometimes finishing with a brief export burst.
- Predictable rhythm brings around 4–6 mode shifts a day (charge, self-use, export) to keep the optimiser aligned with prices.
- Midday opportunities add extra charging or exporting around solar peaks or grid-service windows on purpose.
- Short idle spells hold between 50–70% state of charge during the day to protect battery health.
When to get in touch
- No charging for more than a day even though you have a cheaper rate overnight.
- Rapid back-and-forth mode changes every 30 minutes for several hours.
- State of charge staying below 15% or above 95% for most of the day.
- Charging during the most expensive half-hour blocks on your tariff.
- Your OEM app showing offline status or missing data for longer than six hours.
What You'll See in Your Manufacturer's App
The way our schedule appears can vary depending on your battery brand
FoxESS
In the FoxESS Cloud and Fox mobile apps, open Devices > Battery > Mode scheduler to view the plan Axle has created.
- You will see Force Charge, Feed-in, and Self Use segments that mirror the overnight charge, daytime self-consumption, and export windows from Axle's plan.
- It is expected that some scheduling segments are toggled off depending on your optimisation plan.
- Short Feed-in blocks around the evening peak or grid service alerts are expected.
GivEnergy
On the GivEnergy portal, go to Portal > Inverter > Remote control (cog) > Remote control history to review Axle's actions. In the mobile app, open Battery tab > Settings to reach the inverter schedule. Here you'll see, in each mode dropdown, the schedule Axle is setting.
- Night-time Charge slots should target 95–100% so you start the day full.
- Discharge or Export windows line up with the expensive half-hours and may appear in clusters in the evening.
A Note on Battery Health
We take battery health very seriously. Our optimiser is designed to:
- Limit cycling: We aim for roughly one full cycle (one full charge and discharge) per day.
- Respect limits: We always operate within the minimum and maximum state of charge levels recommended by the manufacturer (e.g., 10-90%).