Antigravity ATX20 guide for RS and HD lithium powersport batteries

What the Antigravity ATX20 is

The Antigravity ATX20 name does not refer to one fixed battery specification. In current product information from Antigravity Batteries, it commonly refers to two YTX20-size lithium iron phosphate powersport batteries: the ATX20-RS and the ATX20-HD. The ATX20-RS is built around the brand’s RE-START function, which is designed to reserve enough energy to recover from an over-discharge event. The ATX20-HD gives up that built-in jump-starting feature in exchange for higher stated capacity and stronger cranking output. For riders, racers, and shop users comparing compact 12-volt lithium batteries, the useful question is not whether the Antigravity ATX20 is “good” in general. It is which version matches the vehicle’s electrical load, charging system, battery access, and storage pattern.

That distinction matters because lithium starter batteries are often sold on weight savings and cranking numbers. In practice, the harder decisions involve charging voltage, parasitic draw, fitment, accessories, and cold-start expectations. This guide summarizes the current manufacturer-stated specifications and explains how to read them before using an ATX20 battery in a motorcycle, UTV, ATV, track car, or other powersport application.

ATX20-RS vs ATX20-HD at a glance

Antigravity’s own materials separate the ATX20-RS and ATX20-HD by function. The RS model is the RE-START version. The HD model is the heavy-duty version. They share a similar YTX20 case footprint, but they are aimed at different priorities.

Specification	Antigravity ATX20-RS	Antigravity ATX20-HD
Battery chemistry	Lithium iron phosphate, 12.8V nominal	Lithium iron phosphate, 12.8V nominal
Main purpose	Built-in RE-START recovery feature	More capacity and cranking power in the ATX20 case size
Cranking output	680 cranking amps	780 cranking amps
Capacity stated by manufacturer	20Ah PbEq, 10Ah actual, 128Wh	30Ah PbEq, 15Ah actual, 192Wh
Weight	3.8 lb	5.18 lb
Approximate case size	6.89 x 3.4 x 5.12 in	6.89 x 3.4 x 5.12 in
Built-in jump-starting	Yes, via RE-START	No
Charge indicator	RE-START system and related controls	Lighted voltage indicator

The table shows the central trade-off. The ATX20-RS is lighter and includes the recovery feature that defines the RE-START range. The ATX20-HD is heavier, but it has higher stated capacity, higher watt-hours, and higher cranking output. In practical terms, the RS is often the more attractive option when the battery is hard to reach and accidental discharge is a concern. The HD is the stronger candidate when the vehicle has higher electrical demand, larger displacement, or accessory loads that make usable capacity more important than the built-in recovery feature.

How to choose between the RS and HD versions

Choose the ATX20-RS when recovery access matters

The ATX20-RS is built around Antigravity’s RE-START concept. According to the manufacturer’s description, the battery management system can place the battery into a sleep state before it is fully drained, preserving enough energy for a restart once the user activates the battery again. That can be useful on motorcycles and powersport vehicles where a rider may leave an accessory on, have a small parasitic drain, or find the battery difficult to access under panels, seats, or luggage.

RE-START should not be treated as a substitute for diagnosing an electrical problem. If a motorcycle repeatedly drains a lithium battery, the likely issue is often a parasitic draw, a charging fault, or a storage practice rather than the battery itself. The feature is best understood as a backup layer, not permission to ignore wiring, alarms, GPS modules, USB chargers, heated grips, or other loads that continue drawing current after the vehicle is shut down.

Choose the ATX20-HD when capacity matters more

The ATX20-HD is the version for users who want more reserve in the same general case size. Antigravity lists it at 30Ah PbEq, 15Ah actual, and 192Wh, compared with 20Ah PbEq, 10Ah actual, and 128Wh for the RS version. It also carries a higher cranking rating. Those figures make it a more logical choice for large touring motorcycles, adventure bikes, heavily accessorized builds, racing applications, and vehicles where the electrical load is more demanding.

The trade-off is clear: the HD model does not have built-in RE-START. It has a lighted voltage indicator instead. A user who values maximum reserve may prefer the HD, while a rider who values the self-rescue concept may prefer the RS. Neither version should be selected only by the cranking amp number. Actual performance depends on engine size, compression, starting behavior, ambient temperature, accessory load, and whether the vehicle’s charging system is within specification.

Be careful with automotive use claims

Antigravity’s product descriptions place important limits on automotive use. The ATX20-RS page states that it is not for automotive applications, except potential race-only uses after contacting the manufacturer. The ATX20-HD page also cautions against street-use automotive applications because of lower amp-hour capacity compared with conventional car batteries. For a track car where weight reduction is important and the electrical system is simple, a compact lithium motorsport battery may make sense. For a street car with daily accessories, security systems, infotainment, lighting loads, and long parking intervals, the ATX20 format may be a poor match unless the application is carefully validated.

Fitment details that matter before installation

The ATX20-RS and ATX20-HD are both presented as lithium replacements for popular YTX20-size lead-acid batteries. Antigravity lists compatibility with common battery families such as YTX15, YTX20, YTX20-BS, YTX20L, YTX20H, YTX20HL, YIX20HL, GYZ20H, GYZ20L, and GYZ20HL. That does not mean every vehicle using one of those labels is automatically a perfect match. It means the case size and terminal concept may fit the battery compartment and cable orientation.

Physical fitment should be checked in three layers. First, confirm the battery tray dimensions and hold-down method. Lithium batteries are lighter, but they still need to be secured against vibration and movement. Second, confirm cable reach and terminal orientation. The four-terminal design on these batteries gives more installation flexibility, but cable routing still needs slack and protection from sharp edges or hot exhaust components. Third, confirm whether the battery is expected to support accessories while the engine is off. A battery that starts the engine well may still be the wrong choice if the vehicle sits for long periods with active electronics.

For more technical explainers on batteries, chargers, and power-system decisions, readers can browse the Taodili Insight archive.

Charging, storage and maintenance limits

The most important technical limit in Antigravity’s user documentation is charging voltage. The manuals specify lithium iron phosphate charging equipment for 12.8V motorsport batteries and list 14.6V as the maximum charging voltage for these models. That single number is critical. A lithium starter battery can be damaged by an incorrect charger, a faulty regulator, or a modified charging system that exceeds the battery’s limit.

Before installing an ATX20 battery, the vehicle’s charging system should be tested. This is especially important on older motorcycles, modified vehicles, and machines with aftermarket regulators or stators. A charging system that was acceptable for a lead-acid battery may not be suitable for a lithium battery if voltage spikes or regulation is unstable. Antigravity’s manuals also warn against using ordinary lead-acid trickle chargers or chargers not intended for lithium iron phosphate chemistry. See also: Tool Categories.

Storage is another area where lithium batteries are often misunderstood. Low self-discharge does not mean zero discharge. If the battery is connected to a vehicle with alarms, ECUs, trackers, USB sockets, clocks, or other parasitic loads, it can still be drained. Manufacturer guidance for these batteries emphasizes checking voltage during storage, keeping the battery in a good state of charge, and maintaining it when the vehicle is not ridden or driven enough to recharge it. For the HD manual, 13.2V is described as a good state of charge, and the documentation warns that deep over-discharge can shorten life and performance.

• Use a charger intended for 12.8V LiFePO4 motorsport batteries.
• Do not exceed the manufacturer-stated maximum charging voltage of 14.6V.
• Check the vehicle charging system before installation.
• Investigate parasitic drain if the battery loses voltage while installed.
• Secure the battery properly even though it is much lighter than lead-acid.
• Do not rely on RE-START or battery management features to mask an electrical fault.

Why the ATX20 line matters in the lightweight battery market

The Antigravity ATX20 line reflects a broader shift in powersport power systems. Riders and builders no longer compare batteries only by case size and cold-cranking labels. They increasingly compare weight, battery management, lithium chemistry, terminal flexibility, reserve energy, accessory behavior, and recovery features. The ATX20-RS and ATX20-HD show two different responses to that demand.

The RS version addresses a common user problem: a battery pulled down by a forgotten switch, an accessory, or a small load. The HD version addresses a different need: more usable energy and cranking strength without moving to a much larger case. This is why a focused “RS vs HD” comparison is more useful than a generic lithium-versus-lead-acid discussion.

For shop owners and technically minded riders, the lesson is to evaluate the whole electrical environment. A lithium battery can cut several pounds compared with many lead-acid equivalents, but weight savings should not be the only specification. The best match is the battery that can start the engine reliably, tolerate the vehicle’s normal charging behavior, support realistic accessory loads, and survive the way the vehicle is stored between rides.

Practical buying checklist

Before buying either Antigravity ATX20 model, work through a short checklist instead of relying on a single headline specification.

1. Identify the battery currently fitted to the vehicle and confirm whether it belongs to the YTX20 or related group.
2. Measure the tray and verify that the ATX20 case size and hold-down method will work.
3. Check the charging voltage at the battery with the engine running and accessories operating.
4. List always-on accessories that may create parasitic drain during storage.
5. Decide whether RE-START recovery or extra reserve capacity is more valuable for the application.
6. Confirm that the charger or maintainer is designed for 12.8V lithium iron phosphate motorsport batteries.
7. Review the manufacturer’s latest fitment notes for special cases such as large V-twins, modified engines, personal watercraft, and street-use automobiles.

This process takes longer than choosing the highest cranking number, but it reduces the risk of buying a battery that looks correct on paper and disappoints in daily use.

Frequently asked questions

Is the Antigravity ATX20-RS the same as the ATX20-HD?

No. They use a similar YTX20-size format, but they are different models. The ATX20-RS has the RE-START feature and lower stated capacity. The ATX20-HD has more stated capacity and cranking output, but it does not have built-in RE-START.

Can an Antigravity ATX20 replace a lead-acid YTX20 battery?

In many powersport applications, it is intended as a lithium replacement for YTX20-size lead-acid batteries and related models. Fitment should still be checked by dimensions, terminal orientation, hold-down method, vehicle charging voltage, and accessory load.

What charger should be used with an Antigravity ATX20?

Use a charger designed for 12.8V lithium iron phosphate motorsport batteries. Antigravity’s documentation warns against using unsuitable lead-acid chargers and states a maximum charging voltage of 14.6V for these models.

Which ATX20 version is better for a touring motorcycle?

It depends on the load profile. A touring motorcycle with more accessories may benefit from the ATX20-HD’s higher stated capacity. A rider more concerned about accidental discharge and recovery access may prefer the ATX20-RS. The charging system and parasitic draw should be checked either way.

Is the Antigravity ATX20 a good choice for a street car?

Usually not as a general street-car battery. Antigravity’s own product information limits automotive use and points users toward caution, especially because compact motorsport batteries have lower amp-hour capacity than conventional street-car batteries. Race-only applications require separate validation.