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Power Budgets
Why battlebot weapons brown out, and how to stop it.
100%
WEAPONS OFFLINE
Battery
120 u
Net while firing
0 u/s
Sustained run
unlimited

How a power budget works

Every battlebot runs on a battery. It holds a fixed amount of energy (its capacity), and it slowly recharges over time. Your weapons draw energy out of it. (Driving is free in the arena, so only weapons drain the battery.)

Think of it like a sink with the tap running and the drain open at the same time. The tap is your recharge; the drain is your weapon draw.

The one rule

If your weapons draw more power than the battery recharges, the battery empties. When it hits zero, your weapons brown out: they cut off until the battery refills. A spinner spins down, a hammer stops swinging, right when you need them.

Sustained run = Battery capacity ÷ (Weapon draw − Recharge)

If your draw is less than or equal to your recharge, the bottom of that fraction is zero or negative, so the answer is unlimited: your weapons never run out.

Where you see this in BotForge

The Stats panel shows a Sustained run stat. That is exactly this number. If it is short (a few seconds), your weapons will die mid fight. That is the single most common mistake when building a bot.

Heavier weapons and faster spinners draw more power. A big battery costs mass (slower bot). Every strong bot is a balance.

Three ways to fix a brownout

  • Bigger battery: more cells = more capacity and faster recharge, but more weight.
  • Lighter or slower weapon: less draw, so the recharge can keep up.
  • Fire less: use one weapon at a time, or pulse it instead of holding it on.

Open the Power Lab tab and try it: push the weapon draw above the recharge, hold fire, and watch the battery die.

Check your understanding