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Battery Simulation

Battery Simulation

Update 0.10.13 introduces a new optional feature: battery simulation. Managing your battery is a tactical component in races that until now has been missing from Liftoff. With this new feature, not only are you limited in how long you can fly on one LiPo, but also in how long you can keep pushing before you destroy the battery. For now the effect is simply an option that can be toggled on or off. Later we will be looking into integrating it into its own game mode.

How does it work?

Since the very beginning of Liftoff we’ve always tried to simulate all internal workings of the drone. This was a big help in simulating the battery. There are two main aspects of battery management: Charge and Voltage.

  • Charge is what most people are familiar with (Think: the battery icon on phone or laptop). Charge drains based on how much power you are drawing. Slow flight will give you several minutes of flight, whereas pushing your drone will bring that down to a minute or less. Extreme maneuvers will also ask more power and drain the battery faster.
  • Voltage might be less obvious and correlates with several other factors. Firstly, a fully charged battery will provide more voltage for a short while. This means that you will have a boost in power at the start of a race. However, this effect slowly fades away and stabilizes. When the battery is about to run out of charge, the voltage will start dropping steeply, greatly reducing the power of the drone — this is the point where you’d want to land your real-life drone. Secondly, voltage is also affected by how much you are asking of your drone. As you push your battery too hard, the voltage will drop below what it should be. This means pushing your drone will negatively impact performance later in the race. Keeping a lower pace after pushing will give the battery some time to recover, and raises the voltage a bit again.

Both charge and voltage are limiting factors in how long you can fly. You can fly slow and steady until you run out of charge, or you can push the drone until the voltage drops below critical levels — and, in future updates, this will destroy your battery in wonderful clouds of smoke.

Visualization

As soon as you enable battery simulation from the main menu, you’ll notice the battery icon in the drone’s OSD. The battery image will show how much charge is left. Next to this, you’ll see the voltage and an arrow. A downward arrow indicates you are pushing the battery too much and voltage is dropping. An arrow pointing up means that the battery is below its limit and is slowly restoring voltage. You can use this as a guide to find the sweet spot in throttle. (Note that voltage will still taper off with charge, so you cannot restore it above that.) We’re displaying the voltage as the actual number, as it would appear in the OSD in a real drone, but we have our concerns about how clear this is for new pilots. It would be great if they can learn new things this way, but we don’t want to leave them confused. We’d love your feedback on this.

Future work

You might notice that some of the built-in races are impossible (or really hard) to finish with battery management on. In particular, the first Hannover race is currently too long at over 2km per lap. We did manage to complete the race in almost 8 minutes of mind-numbingly slow flight, so there’s a challenge for you. We’ll be looking into fixing this in the near future, perhaps by adding battery swap areas.

We’ll also be adding a “Purist” mode, with its own leaderboards. We don’t want to take away the rush of going all-out and not having to worry about such realistic concerns as overdrawing power, but we also don’t want an unfair disadvantage –or advantage in short races– for people flying with battery management.

Last but not least we’ll be implementing a visual indication for a burning LiPo, so it will be immediately obvious what’s going on.

Feedback!

We would love your feedback on every aspect of battery management. Do the flight time and the difference in power feel correct? Is the visualization clear? Do you think this will add more tactics to races? Let us know what you think!