Backup Hours: Blackout Time
Hours of battery you have left, based on whatever you have actually got running.
Download on the App Store
Screenshots
Features
A number in the middle of a blackout
Bushfire season knocks the power out and the question is always the same: how long have we got? Tick what is running and Backup Hours estimates the hours the battery should give on that load.
Enter the inverter once and forget it
Capacity in amp-hours, system voltage, battery type and how far down you are happy to take it. Every blackout after that is just ticking boxes.
Know what the aircon is costing you
Untick it and the remaining hours jump before you have touched the remote. Choosing what to shut down is easier when you can see the trade.
Sitting on the Lock Screen
A Live Activity keeps the countdown visible, so nobody is unlocking a phone in the dark to have a look. The widget shows the same thing on the Home Screen.
Tuned to your battery, not the sticker
A battery three summers old will not hold what the label reckons. Log how the last blackout really went and the app works the usable capacity out of your own history.
Peukert built in
Pull hard on a lead-acid bank and it gives up less than the plain sum promises. The estimate allows for it, and heat out here does not help either.
The power just dropped out. Backup Hours answers the only question that
matters right then: how many hours is the battery good for, with the
appliances you have actually got running?
Enter your inverter or UPS once — battery capacity in Ah, system voltage,
battery type (flooded, AGM, gel or LiFePO4) and how deeply you are
willing to discharge it. From there you just tick whatever is running.
The remaining time recalculates with every tick, so you can see what
turning off the aircon buys you before you turn it off.
A Live Activity keeps the countdown on the Lock Screen, so you are not
unlocking the phone in the dark just to have a look.
Batteries age, and a three-year-old battery does not hold what the label
reckons. Log what actually happened after an outage and the app works out
your battery's real usable capacity from your own history, instead of
trusting the number printed on the case.
The estimate applies the Peukert relationship, so a heavy load is not
simply capacity divided by watts — pulling harder takes more out of a
lead-acid battery than the plain sum suggests.
It is all an estimate to help you plan, never a guarantee. Battery
condition, heat and wiring all move the real number. Nothing is measured
by the phone, no sensor is needed, and all data stays on the device. Do
not rely on this app to keep medical equipment or any other life-critical
gear running.