Antigravity Lithium Battery Review: Subaru Winter Prep

An Antigravity lithium battery is a LiFePO4 (lithium iron phosphate) starting battery with a built-in management system and wireless jump-start that drops into your car in place of a heavy lead-acid unit. The question every Subaru owner asks before winter is simple: will a lithium battery still crank a cold boxer engine at 6 a.m. in January? After running Antigravity RE-START packs through Tampa cold snaps and stress-testing them for out-of-state customers who daily-drive in snow, our answer is a qualified yes — with a few honest caveats about cold-weather chemistry that most product pages will not tell you. This review breaks down the specs, the real winter behavior, the AGM alternative, and how to pick the right group size for your Subaru.

What Is the Antigravity RE-START Lithium Battery?

The Antigravity RE-START is a lithium (LiFePO4) car battery designed to replace a standard lead-acid battery at a fraction of the weight while adding a built-in emergency jump-start. The reviewed unit, the Group 24R (part number AG-24R-40-RS), carries 40 amp-hours of capacity and delivers 1,500 cranking amps — more than enough headroom for a four- or six-cylinder Subaru. It weighs roughly 15.6 lb versus about 40 lb for a comparable lead-acid Group 24, a savings of around 25 lb sitting over the front axle.

Two features separate it from a cheap lithium powersports battery. First, the onboard Battery Management System (BMS) provides over-discharge, over-charge, short-circuit, thermal, and cell-balancing protection, so the pack shuts itself down before it can be damaged. Second, the RE-START function: if the BMS ever cuts power because the battery drained (dome light left on, long storage), you press the button on the included wireless keyfob, the battery releases its reserve, and you start the car and drive away — no jumper cables, no second vehicle. That single feature is why we recommend it over most lithium competitors for a daily driver.

Do Lithium Batteries Work in Winter Cold?

Yes — lithium starting batteries work in winter, but their behavior below freezing is different from lead-acid and you have to account for it. LiFePO4 cells gain internal resistance in the cold, so at roughly 39°F and below your very first crank of the morning can feel sluggish or hesitate. This is normal chemistry, not a defective battery: the act of discharging warms the cells, so a second crank attempt fires normally. Antigravity lists an average operating range of -4°F to 77°F (-20°C to 25°C), with a maximum not to exceed 176°F (80°C).

There is a simple pro trick we teach every customer buying lithium for a cold climate: wake the battery up before you crank. Turn on the headlights or rear defroster for 30 to 60 seconds. That small current draw self-heats the cells and raises available cranking power, so the starter sees a stronger battery. In genuinely brutal, sustained sub-zero weather, size up in amp-hours — a larger-capacity Antigravity has more thermal mass and cranks harder cold, and the RE-START reserve function can behave unpredictably if the battery is undersized for the temperature. For a garaged or daily-driven Subaru in most of the U.S., the 40Ah Group 24R is correctly sized. For an unheated driveway in the upper Midwest or mountain West, read the AGM comparison below before you buy.

Reviewed: Antigravity Group 24R RE-START

In our shop, the customers happiest with lithium are the ones building lighter, quicker cars and those who park in a garage. Subaru owners chasing weight reduction love pulling 25 lb off the front corner, and the RE-START feature has bailed out more than one customer who left an accessory on overnight. The trade-off is honest: pay more up front, respect the cold-start routine, and this is a battery you replace far less often.

AGM vs. Lithium for Winter: Which Cranks Better in the Cold?

For the coldest climates, a premium AGM battery still cranks harder at startup than lithium — and the Odyssey Extreme 34-PC1500T is the one we reach for. AGM (absorbed glass mat) chemistry does not lose as much cranking power in deep cold, and Odyssey rates this Group 34 at 850 cold cranking amps at 0°F, 1,050 cranking amps at 32°F, and 1,500 pulse hot cranking amps for a 5-second start. It also carries a 135-minute reserve capacity, so accessories and a plow motor will not leave you stranded, and the sealed dry-cell TPPL design can mount in almost any position.

The decision comes down to priorities. Choose lithium (Antigravity) if you want big weight savings, near-zero self-discharge, and the RE-START safety net, and you can accept the cold-start routine. Choose AGM (Odyssey) if maximum first-turn cranking in sub-zero weather and simplicity matter more than weight. The Odyssey also happens to fit domestic trucks and SUVs that use a Group 34 case, which makes it a strong winter pick beyond the Subaru crowd. Note the terminal layout differs, so confirm the group size before you order either one.

The AGM Alternative: Odyssey Extreme 34-PC1500T

Antigravity Lithium vs. Odyssey AGM: Winter Spec Comparison

Here is how the top pick stacks up against the AGM alternative and the rest of the Antigravity RE-START lineup we stock. Cranking figures are the manufacturer ratings; match the group size to your vehicle before ordering.

Which Antigravity Battery Fits Your Subaru? Group Sizes Explained

Antigravity builds the same RE-START technology in every common group size, so the right choice is whichever one matches your factory battery tray and terminal layout. The Group 24R we reviewed is a reverse-terminal (positive-on-the-right) case common on many Nissan/Infiniti, Honda/Acura, Lexus, and some Subaru applications. Most modern turbo Subarus — the WRX and STI — actually leave the factory with a Group 25/Q85-style battery, so confirm your car’s exact group before buying rather than assuming the 24R drops in. When in doubt, pull your current battery and read the group number printed on the label, or call our shop and we will match it.

For European and domestic platforms, the same line covers the H6/Group 48 case (common on VW, Audi, BMW, and Volvo) and the larger T6/L2 for big-displacement engines, while the Group 75 covers older GM and Chrysler side-terminal fitments. Below are the other RE-START sizes we keep in stock — pick the one that matches your OE group.

How to Winterize Your Car Battery: A Cold-Weather Checklist

Cold weather is the number-one killer of car batteries, and a little prep in the fall prevents a no-start in the driveway. Whether you run the Antigravity lithium above or an AGM, work through this checklist before the first hard freeze:

• Load-test the battery now. A battery that reads 12.6V at rest can still fail under a cold cranking load. Have it tested before winter, not during it.
• Clean and protect the terminals. Corrosion adds resistance exactly when you need every amp. Wire-brush the posts and add felt washers or dielectric grease.
• Keep it charged. A battery at full charge resists freezing far better than a discharged one. On a stored or seldom-driven car, connect a quality maintainer.
• Use the pre-warm trick with lithium. Turn on headlights or the defroster for 30–60 seconds before cranking to wake the cells.
• Size up for sub-zero. If you park outside in a genuinely cold climate, choose a higher amp-hour lithium or a high-CCA AGM like the Odyssey.
• Park inside when you can. Even an unheated garage keeps the battery meaningfully warmer than an open driveway overnight.

Our team at NLP Performance in Tampa, FL ships batteries and cold-weather electrical parts nationwide, and we are happy to confirm your group size before you order. Browse the full lineup in our batteries collection, or pair your new battery with a smart maintainer to keep it topped off all winter.