ST-550 American Bass Audio Stealth 550 | 55Ah AGM Battery | Maintenance-Free, Sealed Power for Car Audio & More

Stealth 550 — 55Ah AGM Car Audio Battery for Serious Builds

The Stealth 550 is where the Stealth Energy lineup by American Bass steps into serious territory. With 55 amp-hours of capacity and support for amplifier setups up to 1500 watts, this sealed AGM battery delivers the kind of deep reserve power that multi-amplifier builds, and high-output subwoofer systems depend on — stable voltage, fast recovery, and the headroom to keep everything performing at full potential during sustained, hard-hitting playback.

Engineered with Absorbed Glass Mat technology inside a fully sealed, maintenance-free ABS enclosure, the ST-550 provides clean, reliable 12-volt power with zero maintenance. A 660A max discharge current (5-second burst) and an ultra-low 7.5mΩ internal resistance translate to fast energy delivery with minimal voltage sag — exactly what your amplifiers need to stay out of clipping and protect your speakers.

Why Choose the Stealth 550?

The ST-550 occupies the performance sweet spot for builders who are running real power. It has the capacity to anchor a dedicated sub amp plus a four-channel setup, or to serve as a beefy secondary battery alongside a stock or upgraded starting battery. At 35 lbs and a 9.02" × 5.43" × 8.31" footprint, it's significantly more powerful than the mid-range options in the lineup while still fitting comfortably in most trunk and cargo area installs. If your system is pushing past 1000 watts and you're noticing dimming lights or inconsistent bass output, the Stealth 550 is built to solve that problem.