The Antigravity ATX20-HD is the Heavy Duty version of the YTX20-size lithium battery, built for bikes that need more usable capacity: accessory-heavy baggers, audio builds, and touring bikes that sit between rides. It carries a larger cell pack than standard lithium batteries in the same case, delivering 780 cranking amps and 30Ah PbEq capacity.

Unlike the RE-START models, the ATX20-HD allows a deeper level of discharge for more usable capacity and sustained cranking power. A voltage indicator button on the case gives a quick charge-level check, and the Bluetooth Battery Tracker adds remote monitoring from a phone.

Features

• 780 cranking amps with 30Ah PbEq capacity, roughly double the capacity of comparable lithium batteries in this case size
• Deeper allowable discharge than RE-START models for more usable energy
• Full battery management system with over-discharge, over-charge, and thermal protection plus real-time cell balancing
• On-case voltage indicator test button
• Standard YTX20 case, drop-in fit with quad-terminal design
• LiFePO4 chemistry with very low self-discharge

Installation Notes

• Charge only with a lithium-compatible (LiFePO4) charger such as the Antigravity SC-2 or SC-4 Super-Charger. Lead/acid chargers, especially those with desulfation or recondition modes, can damage lithium batteries.
• No built-in RE-START jump starting on this model; keep a maintainer connected during long storage or add the Bluetooth Battery Tracker to watch voltage remotely.
• Check state of charge every 4 to 6 months if the bike carries parasitic drains such as alarms, trackers, or always-on accessories.

Specifications

• Voltage: 12V
• Cranking amps: 780 CA
• Capacity: 30Ah PbEq (15Ah actual), 192Wh
• Case: YTX20
• Chemistry: LiFePO4 with full BMS

Fitment

Direct replacement for the YTX15, YTX20, YTX20-BS, YTX20L, YTX20L-BS, YTX20H, YTX20H-BS, YTX20HL, YTX20HL-BS, YIX20HL, GYZ20H, GYZ20L, and GYZ20HL battery positions. Covers the Harley-Davidson 65989-90B and 65991-82B series batteries in Softail, Dyna, and 1979-2003 Sportster models, and the Indian OEM 4081841 battery in 2014-2024 Thunderstroke and Challenger-platform models.