Answers about battery optimisation, smart tariffs, supported devices, subscriptions and account security.
This can be alarming at first, but it's intentional. PredBat calculates the optimal battery level based on upcoming solar generation, electricity prices, and your typical energy usage. If it predicts sufficient solar generation or cheaper rates before you need the power, it may allow batteries to discharge to maximise overall savings. The system is designed to ensure you have power when you need it during expensive periods.
PredBat makes decisions based on the overall cost optimisation across the day, not just individual cheap periods, whilst considering the health of your battery. Continuous cycling can reduce battery lifespan and may not always result in the best financial outcome when considering round-trip efficiency losses and upcoming usage patterns. You can choose to set your system to cycle more for maximum returns or cycle less for extended battery life.
The savings shown on your PredBat dashboard are calculated by our Savings Calculator. The calculator compares the savings generated by PredBat over a 24-hour period, compared to what you would have saved had you left your inverter in its self-use setting. On most inverters, this setting automatically uses excess solar to charge the battery and then discharge that stored energy to power your home when solar production drops, aiming to maximise self-consumption and minimise grid imports.
PredBat uses its own sophisticated forecasting model which continually calibrates by comparing your actual solar generation over the previous few days with solar forecasts. If you see a disparity between your actual solar generation and what PredBat predicted, don't worry, this is likely due to current irregular day-to-day weather conditions. These disparities are unlikely to significantly impact PredBat's performance. We monitor overall performance to make sure that your ongoing savings are as good as they can be.
PredBat learns your typical energy usage patterns, but we understand life isn't always routine. We're working on features that will allow you to manually schedule high electricity usage events (like cooking for guests or running the washing machine) so PredBat can factor these into its optimisation.
When you switch to Demo mode, PredBat immediately resets your inverter to safe defaults: the scheduled charge window is cleared, reserve is set to 0%, and the SOC target is set to 100%. After that one-time reset, PredBat continues to calculate and display a plan but stops sending any commands to your inverter — your inverter falls back to its own built-in behaviour. When you switch back to Control mode, PredBat resumes sending commands on its next planning cycle (within 5 minutes).
An 'Unhealthy' status usually means PredBat couldn't retrieve data from your inverter or energy provider in the last few minutes. This often resolves itself — wait 5–10 minutes and refresh. If it persists, go to Settings and use 'Validate API Keys' to check your connections. Common causes: inverter briefly offline, energy provider API being slow, or a network blip at your home. If validation passes but the status stays red for more than an hour, contact support.
Temporary API errors are almost always caused by a brief outage at your energy provider or inverter manufacturer's cloud API — not a problem with your PredBat subscription. PredBat automatically retries and resumes normal operation once the external API recovers, typically within minutes. If errors persist for more than a few hours, go to Settings → API Keys and re-enter your key to force re-validation. Battery optimisation continues from the last known plan during short API outages so your system isn't left unmanaged.
Each row of the Energy Plan shows what PredBat intends your battery to do in that half-hour slot. "Demand" is normal running — your home is powered by solar and/or battery, and any spare solar tops up the battery or is exported once it's full. "Charge" means PredBat is charging the battery from the grid, usually during a cheap period. "Export" means the battery is being discharged to sell power to the grid during a high export price. The "Freeze" and "Hold" states all mean PredBat is deliberately keeping your battery level steady rather than charging or draining it: "Freeze Charge" holds the battery at its current level — it won't be drained, and only surplus solar is allowed to top it up (useful just before you'll need that energy, or when importing is cheap). "Hold Charge" is PredBat's automatic version of the same thing — it aims for a level at or below where you already are, so nothing actually charges and the battery simply holds. "Freeze Export" keeps the battery at its current level while sending spare solar to the grid instead of storing it (if solar falls short, the battery covers the gap) — you'll often see this around a good export window or an Octopus saving session. The small symbol beside each state (for example a snowflake for the freeze modes) is just a visual marker for that mode.
PredBat integrates seamlessly with IOG, automatically detecting your cheap rate periods and optimising battery charge/discharge around them. It monitors your IOG schedule and adjusts its plans as Octopus updates your cheap rate periods based on your EV charging needs.
Yes, PredBat can always see what tariff you are on so as soon as Octopus confirms your tariff switch, PredBat will adjust its plan accordingly.
Yes, PredBat can see upcoming Savings and Free Sessions and will build them into your plan to maximise your savings.
PredBat integrates with Axle Energy VPP dispatch events. When an event is scheduled, PredBat factors it into its battery plan — holding charge for export during high-demand windows or pausing discharge as required. Your battery automatically returns to normal optimisation after each event. If you're using a different VPP or demand response provider, contact support so we can confirm compatibility with your specific service.
GivEnergy, Fox ESS, SolaX, and Solis inverters are currently supported. We're constantly adding compatibility with other manufacturers so watch this space.
Currently, PredBat focuses on optimising your home battery and solar system. While it's aware of your EV charging schedule (particularly when on Intelligent Octopus Go), it doesn't directly control when your car charges. You'll need to manage EV charging separately, though PredBat will factor your EV charging habits into its planning decisions.
We're working on enhanced vehicle management features that will allow you to specify which vehicle is plugged in for better optimisation.
Many users successfully run PredBat alongside heat pumps. PredBat factors your heat pump's electricity consumption into its optimisation decisions. We're exploring enhanced integration features to better optimise heating costs during winter months.
No. PredBat Cloud at predbat.com is a fully managed, paid cloud service — no Home Assistant or technical setup is required. Just connect a supported inverter and energy account. It is distinct from the open-source Predbat project, which is commonly self-hosted as a Home Assistant add-on.
From the PredBat dashboard, you can set a minimum battery reserve that will help ensure you always have backup power available for emergencies, which is particularly important in areas with unreliable grid supply. It is worth noting that increasing this reserve limit can reduce the potential savings that PredBat can generate for you. There is also a Storm Watch function which means PredBat will know when a storm is forecast and plan to charge your battery a little more than average before the storm hits in case of power cuts.
Some inverter firmware versions (particularly older GivEnergy models) automatically reset the battery reserve to a default value after a power cycle or firmware update. PredBat re-applies your configured reserve on every planning cycle (every 5 minutes), so any firmware reset is corrected quickly. If you need a consistently higher reserve for backup power, set 'Reserve Min' in your PredBat Settings — this ensures PredBat will always restore your preferred reserve level after any reset.
PredBat works within whatever export constraints your inverter hardware enforces. You should configure your G99 maximum export rate directly in your inverter settings (not via PredBat) — your installer will have set this up during commissioning. Once the hardware cap is in place, PredBat's optimisation automatically works within that limit. If you're unsure what limit applies to your installation, check your G99 approval letter from your DNO or ask your installer.
PredBat is aware of your Ohme charging schedule when you're on a supported smart tariff such as Intelligent Octopus Go. It factors your planned EV charging load into its battery optimisation decisions so it doesn't try to export or deplete the battery during your scheduled Ohme charge sessions. Direct on/off control of your Ohme charger is not currently available from PredBat, but the integration ensures the two systems don't conflict with each other.
After your trial ends, your subscription will begin automatically. You can cancel at any time before the trial ends and you won't be charged.
Yes. Cancel from your account settings at any time. No cancellation fees or lock-in periods.
If after 12 paid months your savings don't cover the subscription cost, you'll receive a credit for the difference. See our Terms of Service for full details.
Savings vary based on battery size, tariff, and usage. Typical users see their subscription pay for itself within the first few weeks.
Your data is encrypted at rest and in transit. We never share your data with third parties. Each customer environment is fully isolated.