The Antigravity ATX20-RS is a lithium-ion replacement for the YTX20-series battery used across Harley-Davidson Softail, Dyna, and older Sportster models, and across Indian's Thunderstroke and Challenger platforms. It delivers 680 cranking amps at 3.8 pounds, roughly a 12 pound saving over the stock lead/acid unit.

The RE-START system monitors state of charge and puts the battery to sleep before it can go completely dead, holding back a reserve of energy. Press the RE-START button, or trigger it through the SAE pigtail with the RE-START Remote, and the bike starts one more time.

A four-terminal design accepts left or right hand negative and positive connections, so one battery covers either tray orientation.

Features

• 680 cranking amps, up to twice the output of a comparable lead/acid battery
• RE-START technology: built-in jump starting from a protected energy reserve
• Full battery management system with over-discharge, over-charge, and thermal protection plus real-time cell balancing
• 3.8 lbs in the standard YTX20 case
• Quad-terminal design fits left or right hand negative connections
• LiFePO4 chemistry with very low self-discharge; holds a charge up to a year without parasitic drains
• Sealed construction, mountable in any orientation

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.
• The RE-START reserve is activated with the button on the battery case, or remotely through the bike's SAE charging pigtail using the Antigravity RE-START Remote.
• Antigravity does not recommend RE-START models for V-twins over 103 cubic inches or high-compression builds because of their higher current draw; the XPS YTX20 and XPS V-12 are the models rated for those applications.
• 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: 680 CA
• Capacity: 20Ah PbEq (10Ah actual)
• Case: YTX20, 6.89 x 3.4 x 5.12 in (L x W x H)
• Weight: 3.8 lbs
• 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.