Power & Electrical
Alternators, batteries & big-3
Alternator Sizing
Calculate total demand and recommended high-output size.
Open →Battery Sizing
How much Ah you need for engine-off playback.
Open →Big-Three Wiring Upgrade
Three cables, lengths by vehicle type, gauge by wattage.
Open →Solar & Dual Battery
Days of autonomy + charge time.
Open →Why these numbers matter
Are these accurate enough to build from?
They use the same formulas the trade does — Thiele/Small for enclosures, voltage-drop tables for wire, load math for charging. Treat the output as a starting spec, then sanity-check against your gear’s manual before you cut wood or crimp lugs.
Do I need an account?
No. Every calculator is free and works without signing in. A free account saves your results so you don’t re-enter numbers at the next show — and gets you partner discount codes.
Why does the alternator calculator recommend so much output?
Alternators make their rated amps at cruising RPM, not idle — output can drop 30–50% sitting still. Since that’s exactly when you’re demoing in a parking lot, the math sizes for idle reality.
A capacitor is cheaper than a battery — why does it say otherwise?
Caps handle millisecond transients; sustained bass draw is a reserve problem. That’s stored energy, which means a battery. The capacitor calculator says so out loud rather than selling you the wrong part.
Want the reasoning behind the math? Read the guides — or find a show to go put the build to work.