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 usage from recent days and re-plans every 5 minutes from what your home is actually using, so it adjusts as the day goes. If you know about a big one-off load in advance, such as cooking for guests or a long tumble-dryer run, add it as Planned Usage on the Dashboard's Manual card and PredBat will plan around it. Lasting changes, such as a new heat pump, are picked up automatically over the following days.
New accounts start in Demo mode: PredBat shows its plan but sends no commands to your inverter, so your inverter keeps running on its own settings. If you switch from Control back to Demo, PredBat first resets your inverter once to safe defaults: it clears its charge and export schedules, sets the charge target to 100% and sets the reserve to your minimum reserve. After that it stops sending commands, and your inverter falls back to its own built-in behaviour. When you switch back to Control, PredBat takes over again 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, use Validate API Keys on the Service Status card on your Dashboard 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's or inverter manufacturer's cloud, not a problem with your PredBat subscription. PredBat retries automatically and carries on once the service recovers, usually within minutes; meanwhile your inverter keeps the last settings PredBat sent. If errors last more than a few hours, use Validate API Keys on the Service Status card on your Dashboard, and check your keys in Settings → Energy Provider API Keys (for your tariff) or Settings → Battery System (for your inverter).
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" stops the battery charging and sends spare solar to the grid instead of storing it (if solar falls short, the battery still covers your home) — 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.
Mostly, yes. If you're signed up to Octoplus and Saving Sessions (now called Power Down) in the Octopus app, PredBat joins each session for you and plans around it, exporting from your battery if you have an export meter; you can ask the assistant to turn automatic joining off. Most Octopus free electricity sessions are picked up automatically too. For Super Sundays, you choose your free hour in the Octopus app and PredBat then plans around it.
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, Solis, Sigenergy and Tesla Powerwall systems are supported, and you can also connect through a PredBat Hub. DEYE, Sunsynk and Enphase are in beta. We're constantly adding other manufacturers, so contact us if yours isn't listed.
PredBat plans your home battery around your car. On Intelligent Octopus Go, Octopus schedules your car's charging and PredBat plans around its slots. If you link a supported charger, such as Ohme, myenergi Zappi or Wallbox, in Settings → Electric Vehicle Setup, PredBat can see when your car is charging and stops your battery discharging into it. Letting PredBat set your charger's schedule itself is currently a beta, enabled one customer at a time.
Yes. On Intelligent Octopus Go, PredBat picks up every car on your Octopus account automatically. Otherwise you can add each car in Settings → Electric Vehicle Setup (car details are currently a beta, enabled one customer at a time). PredBat works with one car charger at a time; multiple chargers aren't supported yet.
Yes. Many customers run PredBat alongside a heat pump. PredBat learns your household's usage patterns, and that includes your heat pump, so your plan allows for the energy it uses. If the weather changes suddenly, such as the first cold snap of winter, it can take a day or two for PredBat to adjust. We're also exploring tighter heat pump integrations for the future.
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.
Yes. On the Dashboard's Manual card, set Minimum under Battery reserve: PredBat never plans to take your battery below it, so you always have backup power for emergencies, which is particularly important in areas with unreliable grid supply. Bear in mind that a higher reserve can reduce the savings PredBat can make for you. You can also turn on Weather Alerts in Settings → Optional Features: when severe weather is forecast for your area, PredBat automatically increases your battery charge beforehand in case of power cuts.
“Keep for peak” asks PredBat to still have some charge left when the expensive evening period arrives. It is the blue handle on the Battery reserve card, and it is a preference rather than a lock: nothing is held back by force. PredBat treats going below that level as though it costs money, so it will still go below it when the saving is worth more, and it never imports from the grid to top back up to it — which makes it quite different from the Minimum beside it, a hard floor your inverter will not cross. The name misleads, so to be blunt: raising it usually costs you money, because charge held back is charge not exported into the evening peak or used to avoid importing. On an export-led tariff such as Octopus Flux the right value is normally 0, and a small buffer of 5–10% is something you are paying for rather than saving with. Setting it near your battery's full capacity is actively harmful: the penalty for discharging can then never be satisfied, so every slot in your plan becomes “Hold Charge”, the battery sits full and your house runs on peak-rate grid all day. If your plan looks like that, check this setting first. The dashboard warns you at 10% and again at 90% for exactly this reason.
The most common cause is another system also controlling your inverter, such as Home Assistant, GivTCP or an automation in your inverter maker's app, so the two keep overwriting each other's settings. Only one system should control your inverter: turn off the other one's control (it can still monitor). Some inverter firmware can also reset the reserve after a power cycle or update; PredBat re-applies its settings every few minutes. To keep a higher reserve for backup power, set Minimum under Battery reserve on the Dashboard's Manual card.
Yes. Your export limit is set in your inverter, normally by your installer during commissioning. PredBat reads it from your inverter and plans around it, so it won't schedule exports above it. If PredBat can't read the limit on your system, our support team can set the value PredBat uses. We can't change your inverter's limit itself: that's a matter for your installer.
Yes. Link your Ohme in Settings → Electric Vehicle Setup. PredBat can then see when your car is charging and stops your battery discharging into it, and on Intelligent Octopus Go it plans around your car's charging slots. Letting PredBat set your Ohme's charging schedule itself is currently a beta, enabled one customer at a time.
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 at any time from Account → Subscription → Manage Subscription. There are 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 with your battery size, tariff, solar and usage, but most of our customers save more than their subscription costs, and some save much more. If, after 12 paid months, your savings don't cover your subscription, our savings guarantee credits you the difference; see the Terms of Service for the conditions.
Your data is encrypted at rest and in transit. We never share your data with third parties. Each customer environment is fully isolated.